Patent Publication Number: US-2006009692-A1

Title: Medical image storage apparatus protectable of personal information

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. P2004-162806, filed on Jun. 1, 2004, the entire contents of which are incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a medical image storage apparatus for storing medical image information including personal information of a patient. The present invention also relates to a medical imaging apparatus for generating and storing the medical image information. The present invention still relates to a medical image system including a medical image storage apparatus and a medical imaging apparatus. The present invention further relates to a method of storing the medical image information.  
     DISCUSSION OF THE BACKGROUND  
      Medical image information is generated from medical imaging apparatuses such as an X-ray diagnosis apparatus, an X-ray computed tomography apparatus, a magnetic resonance imaging apparatus, an ultrasound diagnosis apparatus, a positron emission tomography apparatus, and the like. The medical image information usually includes image data and accompanying information and is stored in a medical image storage apparatus. The accompanying information usually includes examination information and patient information. Therefore, the medical image information includes personal information such as a patient name, patient identification information, and the like, which can identify a patient of the image data. This means that the medical image information is included in a category of individual privacy information and should be protected according to several acts including the Health Insurance Portability and Accountability Act (HIPPA).  
      Although the medical image information should be administered strictly and protected from the information leakage, it is not possible to deny that there is a possibility that personal information included in the medical image information would be leaked when the medical image information is used for the purpose other than a medical practice. For example, it may occur when the medical image information is used to research images based on the medical image information or when the medical image information is used during a maintenance service of the medical image storage apparatus.  
      In order to solve this type of problem, for example, Japanese Patent Application Publication No. 2002-197186 describes a technique of storing information disclosure procedures set by a patient or his/her doctor in a medical information management system in advance and allowing to refer to medical image information only in accordance with the procedures so that the medical image information could not be unintentionally disclosed.  
      This technique, however, still allows the doctor to edit or process the medical image information irrespective of the purpose of use as long as the doctor is allowed to access the medical image information. Therefore, when the medical image information is used for the purpose of researching images based on the medical image information or for other non-medical purpose, it may still occur that part of personal information included in the medical image information is leaked by careless operations since it is cumbersome to remove the personal information from the medical image information.  
      Also when a maintenance service staff maintains the medical image storage apparatus, the staff may happen to leak part of the personal information by mistake if the staff is not so familiar with treating the personal information.  
      Meanwhile, there is no way for the patient to see if the medical image information is strictly archived in security and used in an appropriate manner.  
      As a technique of securing personal information, Japanese Patent Application Publication Nos. 2000-13614 and 2002-247026 describe a technique of dividing the medical image information into image data and accompanying information and encrypting the accompanying information when the medical image information is transmitted through a network so as to avoid personal information included in the accompanying information from being unintentionally taken by the third person during the transmission. This is, however, only for the security during the transmission and the encrypted accompanying information is decrypted after the reception of the medical image information. These documents neither describe nor suggest any good idea for securing the personal information and solving the above-mentioned problems once after the medical image information has been stored in the medical image storage apparatus or the like.  
     SUMMARY OF THE INVENTION  
      According to the first aspect of the present invention, there is provided a medical image storage apparatus. The apparatus includes a receiving unit, a table preparation unit, the first storage unit, the second storage unit, the first unit, the second unit, and an output unit. The receiving unit is configured to receive medical image information resulting from a medical imaging apparatus. The table preparation unit is configured to prepare a table of a relationship between predetermined personal information concerning the medical image information and image information prepared by removing the predetermined personal information from the medical image information. The first storage unit is configured to store the predetermined personal information. The second storage unit is configured to store the image information. The first unit is configured to make the table unavailable. The second unit is configured to recapture the table. The output unit is configured to read the predetermined personal information from the first storage unit and the image information from the second storage unit based on the recaptured table and to prepare and output the medical image information.  
      According to the second aspect of the present invention, there is provided a medical imaging apparatus. The apparatus includes an imaging unit, a table preparation unit, the first storage unit, the second storage unit, the first unit, the second unit, and an output unit. The imaging unit is configured to generate medical image information. The table preparation unit is configured to prepare a table of a relationship between predetermined personal information concerning the medical image information and image information based on the medical image information. The first storage unit is configured to store the predetermined personal information. The second storage unit is configured to store the image information. The first unit is configured to make the table unavailable. The second unit is configured to recapture the table. The output unit is configured to read the predetermined personal information from the first storage unit and the image information from the second storage unit based on the recaptured table and to prepare and output the medical image information.  
      According to the third aspect of the present invention, there is provided a medical image system including a medical imaging apparatus and a medical image storage apparatus. The system includes an imaging unit, a table preparation unit, the first storage unit, the second storage unit, the first unit, the second unit, and an output unit. The imaging unit is configured to generate medical image information. The table preparation unit is configured to prepare a table of a relationship between predetermined personal information concerning the medical image information and image information based on the medical image information. The first storage unit is configured to store the predetermined personal information. The second storage unit is configured to store the image information. The first unit is configured to make the table unavailable. The second unit is configured to recapture the table. The output unit is configured to read the predetermined personal information from the first storage unit and the image information from the second storage unit based on the recaptured table and to prepare and output the medical image information.  
      According to the fourth aspect of the present invention, there is provided a method of storing medical image information. The method begins by receiving medical image information resulting from a medical imaging apparatus. The method continues by preparing a table of a relationship between predetermined personal information concerning the medical image information and image information prepared by removing the predetermined personal information from the medical image information. The method still continues by storing the predetermined personal information, storing the image information, and making the table unavailable.  
      According to the fifth aspect of the present invention, there is provided a method of storing medical image information. The method begins by generating medical image information. The method continues by preparing a table of a relationship between predetermined personal information concerning the medical image information and image information based on the medical image information. The method still continues by storing the predetermined personal information, storing the image information, and making the table unavailable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      A more complete appreciation of embodiments of the present invention and many of its attendant advantages will be readily obtained by reference to the following detailed description considered in connection with the accompanying drawings, in which:  
       FIG. 1  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the first embodiment;  
       FIG. 2  is an illustration showing an example of divining medical image information according to the first embodiment;  
       FIGS. 3A and 3B  are illustrations showing an example of a table to be encrypted according to the first embodiment;  
       FIG. 4  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus according to the first embodiment;  
       FIG. 5  is a flowchart showing the first exemplary flow of delaying a transfer or a divining operation according to the first embodiment;  
       FIG. 6  is a flowchart showing the second exemplary flow of delaying the transfer or the divining operation according to the first embodiment;  
       FIG. 7  is a flowchart showing the third exemplary flow of delaying the transfer or the divining operation according to the first embodiment;  
       FIG. 8  is an illustration showing an example of a step to replace one of steps shown in  FIG. 5, 6 , or  7 ;  
       FIG. 9  is an illustration showing another example of a step to replace the one step shown in  FIG. 5, 6 , or  7 ;  
       FIG. 10  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus according to the first embodiment;  
       FIG. 11  is a flowchart showing an exemplary flow of outputting the image information in the medical image storage apparatus according to the first embodiment;  
       FIG. 12  is a block diagram showing another exemplary configuration of the medical image storage apparatus according to the first embodiment;  
       FIG. 13  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the second embodiment;  
       FIG. 14  is a flowchart showing an exemplary flow of writing the table to an IC card according to the second embodiment;  
       FIG. 15  is an illustration showing an example of a table to be stored in the IC card according to the second embodiment;  
       FIG. 16  is a flowchart showing an exemplary flow of outputting the medical image information according to the second embodiment;  
       FIG. 17  is a block diagram showing a modified exemplary configuration of the medical image storage apparatus according to the second embodiment;  
       FIG. 18  is a block diagram showing another exemplary configuration of the medical image storage apparatus according to the second embodiment;  
       FIG. 19  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the third embodiment;  
       FIG. 20  is an illustration showing an example of a table to be encrypted according to the third embodiment;  
       FIG. 21  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus according to the third embodiment;  
       FIG. 22  is a block diagram showing another exemplary configuration of the medical image storage apparatus according to the third embodiment;  
       FIG. 23  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the fourth embodiment;  
       FIG. 24  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus according to the fourth embodiment;  
       FIG. 25  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the fifth embodiment;  
       FIG. 26  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus according to the fifth embodiment;  
       FIG. 27  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus according to the fifth embodiment;  
       FIG. 28  is a block diagram showing an exemplary configuration of a medical imaging apparatus according to the sixth embodiment;  
       FIG. 29  is a block diagram showing a modified exemplary configuration of the medical imaging apparatus according to the sixth embodiment;  
       FIG. 30  is an illustration showing an example of a medical image system according to the seventh embodiment;  
       FIG. 31  is an illustration showing another example of the medical image system according to the seventh embodiment; and  
       FIG. 32  is an illustration showing an example of the IC card according to the embodiments. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Embodiments of the present invention will be described with reference to the accompanying drawings.  
     First Embodiment  
       FIG. 1  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the first embodiment. A medical image storage apparatus  10  such as, for example, an image filing server, may include a receiving unit  1 , a medical image information processing unit (hereinafter referred to as an image processing unit)  2 , a storage unit  3 , a medical image information output unit (hereinafter referred to as an output unit)  4 , a table processing unit  5 , an operation unit  6 , and a control unit  7 .  
      The receiving unit  1  is connected to a medical imaging apparatus such as, for example, an X-ray diagnosis apparatus, an X-ray computed tomography apparatus (hereinafter referred to as an X-ray CT apparatus), a magnetic resonance imaging apparatus, a nuclear medicine diagnosis apparatus, an ultrasound diagnosis apparatus, an endoscope apparatus, and/or the like. In  FIG. 1 , an X-ray CT apparatus  80  is connected to the receiving unit  1  through a network such as a hospital LAN (Local Area Network). The receiving unit  1  receives medical image information including image data and its accompanying information. The image data pertains to X-ray CT image data generated by the X-ray CT apparatus  80 . The image data may also be X-ray CT image data image-processed by the X-ray CT apparatus  80 . The image data may be two-dimensional or three-dimensional image data. The image data may include imaging condition information such as, for example, imaging parameters and imaging time. The accompanying information includes, for example, patient information and examination information, which concerns the image data. The patient information includes, for example, a patient name, patient identification information, patient&#39;s date of birth, patient&#39;s sex, and the like, which can usually be treated as personal information of the patient. The examination information may include, for example, an examination date, an imaged part of the patient, a type of a medical imaging apparatus (herein, an X-ray CT apparatus), and the like. The image data and the examination information may also include personal information of the patient. The personal information may be information which can identify the patient by itself or with other information of the patient.  
      The image processing unit  2  may include a medical image information storage unit  21  and a medical image information dividing unit  22 . The image processing unit  2  may correspond to ‘a table preparation unit’.  
      The medical image information storage unit  21  temporarily stores the medical image information received by the receiving unit  1 . The stored medical image information, which is original medical image information, may be deleted from the medical image information storage unit  21  in accordance with a predetermined condition so that a doctor, a radiological technologist, or the like (hereinafter referred to as a user) cannot obtain the original medical image information unless permitted or without the patient&#39;s help.  
      As shown in  FIG. 2 , the medical image information dividing unit  22  divides the medical image information  210  into predetermined personal information  220  and image information  230 . All or part of the personal information may be determined as the predetermined personal information  220  in accordance with a predetermined rule. The predetermined personal information  220  may be extracted from the medical image information  210 . The medical image information  210  from which the predetermined personal information  220  is removed is treated as the image information  230 . The image information  230  may, however, include dummy information  240  instead of the removed predetermined personal information  220 . Since a medical image storage apparatus can typically recognize where each kind of information is stored, the medical image information dividing unit  22  can extract the predetermined personal information. Especially, when the medical image information is stored in compliance with the DICOM (Digital Imaging and Communication in Medicine) standard, the medical image information dividing unit  22  can extract the predetermined personal information according to tag information.  
      The medical image information dividing unit  22  also issues identification information of the predetermined personal information (hereinafter referred to as personal information ID) and identification information of the image information (hereinafter referred to as image information ID). The personal information ID is given to the predetermined personal information and the predetermined personal information given the personal information ID is transferred to the storage unit  3  as ID-given predetermined personal information. Similarly, the image information ID is given to the image information and the image information given the image information ID is transferred to the storage unit  3  as ID-given image information. The personal information ID is uniquely issued to each medical image information so that the predetermined personal information can be distinguished among the examinations. Similarly, the image information ID is uniquely issued to each medical image information so that the image information can be distinguished among the examinations. Each of the personal information ID and the image information ID does not relate to an issue system in a table storage unit  52  and comprises arbitrary numeral and/or character information which is not displayed in a display unit  43 .  
      The medical image information dividing unit  22  further prepares a table of a relationship between the predetermined personal information and the image information. For example, the medical image information dividing unit  22  prepares a preliminary table including the personal information ID, the image information ID, and the examination date. The examination date may be obtained from the examination information included in the medical image information. As shown in  FIG. 3A , the medical image information dividing unit  22  then prepares the table by adding unique information to the preliminary table. The unique information is uniquely given or issued to each patient such as, for example, patient&#39;s health insurance card information, patient&#39;s registration card information, password information determined by a patient, or any patient-distinguishable information. This unique information may be input from the operation unit  6 . The prepared table is transferred to the table processing unit  5 .  
      The storage unit  3  may be configured by a non-volatile memory device such as, for example, a magnetic disk and include an image information storage unit  31  and a personal information storage unit  32 . The image information storage unit  31  stores the ID-given image information. The personal information storage unit  32  stores the ID-given predetermined personal information. The image information storage unit  31  may correspond to ‘a second storage unit’. The personal information storage unit  32  may correspond to ‘a first storage unit’.  
      The output unit  4  may include a medical image information preparation unit  41 , an image information retrieval unit  42 , and the display unit  43 . The medical image information preparation unit  41  receives the table (decrypted table) from a table decryption unit  53  and retrieves from the image information storage unit  31  the ID-given image information whose ID corresponds to the image information ID obtained from the table. The medical image information preparation unit  41  also retrieves from the personal information storage unit  32  the ID-given predetermined personal information whose ID corresponds to the personal information ID obtained from the table. The medical image information preparation unit  41  also prepares medical image information by combining the retrieved image information and the predetermined personal information and transfers the medical image information to the display unit  43 . The image information retrieval unit  42  retrieves the (ID-given) image information from the image information storage unit  31  in accordance with a request from the operation unit  6  and transfers the image information to the display unit  43 . The display unit  43  displays the medical image information when the medical image information is transferred from the medical image information preparation unit  41 . In this case, the display unit  43  displays the image information and the personal information included in the medical image information. The display unit  43  displays the image information when the image information is transferred from the image information retrieval unit  42 . In this case, the display unit  43  does not display the personal information.  
      The table processing unit  5  may include a table encryption unit  51 , the table storage unit  52 , and a table decryption unit  53 . The table encryption unit  51  receives the table transferred from the medical image information dividing unit  22  and encrypts the table. The encrypted table is transferred to and stored in the table storage unit  52 . The table encryption unit  51  may store an encryption key, particularly when the encryption key is a public key of the patient. The encryption key may alternatively be stored in an IC (Integrated Circuit) card  81 , which may be kept and administered by the patient. In this case, the encryption key is read from the IC card  81  through the operation unit  6  and provided to the table encryption unit  51  through the control unit  7 . When the table is encrypted, only the personal information ID and the image information ID may be encrypted so that the examination date and the unique information can be used in the retrieval of the encrypted table, as shown in  FIG. 3B . The table encryption unit  51  may correspond to ‘a first unit configured to make the table unavailable’.  
      The table decryption unit  53  retrieves the encrypted table in accordance with the unique information (and the examination date) and decrypts the encrypted table. The decrypted table is transferred to the medical image information preparation unit  41  as the table. In the decryption, the table decryption unit  53  uses a decryption key. When the table encryption unit  51  uses the public key, the table decryption unit  53  uses a private key corresponding to the public key as the decryption key. The decryption key including the private key may be stored in the IC card  81 . Therefore, in this case, the decryption key including the private key is read from the IC card  81  through the operation unit  6  and provided to the table decryption unit  53  through the control unit  7 . The table decryption unit  53  may correspond to ‘a second unit configured to recapture the table’.  
      The operation unit  6  may include an IC card reader  61 , various switches, and an input device such as, for example, a keyboard, a trackball, a mouse, a magnetic card reader, a bar code reader, and/or the like. When an external memory medium  8  is the IC card  81 , the IC card reader  61  is used. When the external memory medium  8  is a magnetic card  82  or a bar code medium  83 , the magnetic card reader or the bar code reader may be used. In the following description, embodiments will be explained taking an example of the time when the IC card  81  is used as an example of the external memory medium  8 . The external medium  8  may be portable and usually kept and administered by the patient. The operation unit  6  may be operative as an interactive interface. The operation unit  6  may be used to input the unique information, various types of information and instructions, the encryption key, the decryption key, and the like. The unique information, the encryption key, and the decryption key may be input through the IC card reader  61 .  
      The control unit  7  may include a CPU (Central Processing Unit) and memory circuitry. The memory circuitry may temporarily store the information, the instructions, the unique information, the encryption key, and the decryption key when these are input from the operation unit  6 . These information may be transferred to one or more appropriate units provided in the medical image storage apparatus  10  or used to control one or more appropriate units or over the medical image storage apparatus  10 .  
      Storing operations of the medical image information will be described with reference to a flowchart shown in  FIG. 4 .  FIG. 4  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus  10  according to the first embodiment.  
      When the X-ray CT apparatus  80  has generated CT image data and its accompanying information as the medical image information, the medical image information is transmitted to the medical image storage apparatus  10  through the hospital LAN. The transmitted medical image information is received by the receiving unit  1 . Although the storing operation can be started in response to a user&#39;s instruction from the operation unit  6 , the storing operation is typically started in accordance with the reception of the medical image information as long as the medical image storage apparatus  10  is ready for receiving and storing the medical image information (step S 1 ).  
      The received medical image information is temporarily stored in the medical image information storage unit  21  (step S 2 ). The medical image information is then transferred to the medical image information divining unit  22  (step S 3 ) and divided into predetermined personal information and image information. That is, the predetermined personal information is prepared by extracting the predetermined personal information from the medical image information. Also using dummy information, the image information is prepared (step S 4 ).  
      The transfer of the medical image information from the medical image information storage unit  21  to the medical image information dividing unit  22  means proceeding to the encryption operation. Once the encryption has been conducted, the user cannot obtain the medical image information unless the decryption key which may be administered by the patient is obtained. Since the user usually needs to interpret or diagnose images resulting from the medical image information, identifying the images concerning a specific patient, the transfer may not be conducted so soon. Or even if transferred, the dividing operation may not be conducted immediately.  
       FIG. 5  is a flowchart showing the first exemplary flow of delaying the transfer or the divining operation according to the first embodiment. In advance of imaging operation in the X-ray CT apparatus  80 , the user usually makes a schedule of imaging (step S 101 ). When the scheduling has been completed, the control unit  7  starts measuring time (step S 102 ). For example, the completion of the scheduling may be informed to the medical image storage apparatus  10  from an apparatus in which the scheduling has been conducted. In accordance to the schedule, the imaging operation is conducted (step S 103 ). After the imaging, it is determined whether a predetermined time has passed from the start of the time measurement (step S 104 ). Since it is necessary to give the user enough time to interpret images, the predetermined time may be set to be long enough for the user to conduct the interpretation after the imaging. When the control unit  7  has determined that the predetermined time has passed, the control unit  7  controls the image processing unit  2  so that the transfer or the dividing operation is made (step S 105 ).  
      Time measurement to proceed to the transfer or the dividing operation may alternatively be made as shown in  FIG. 6 .  FIG. 6  is a flowchart showing the second exemplary flow of delaying the transfer or the divining operation according to the first embodiment. The time measurement may start (step S 112 ) when the imaging has been completed (step S 111 ). For example, the control unit  7  may start the measurement in response to the reception of the medical image information by the receiving unit  1 . When the control unit  7  has determined that the predetermined time has passed (step S 113 ) the control unit  7  controls the image processing unit  2  so that the transfer or the dividing operation is made (step S 114 ).  
      A further alternative way of the measurement is shown in  FIG. 7 .  FIG. 7  is a flowchart showing the third exemplary flow of delaying the transfer or the divining operation according to the first embodiment. This is a case that the time measurement may be started in response to accounting or payment at a hospital. One example of this case may be when the patient is admitted to a hospital. After the patient has been admitted to the hospital (step S 121 ), imaging operation is conducted on the patient (step S 122 ). When the patient is discharged from the hospital (step S 123 ), the patient usually has to make a payment. The payment information may be input to an accounting system by an accounting staff (step S 124 ). For example, the completion of the accounting processing may be informed to the medical image storage apparatus  10  from the accounting system. In response to the information from the accounting system, the control unit  7  starts measuring time (step S 125 ). When the control unit  7  has determined that the predetermined time has passed (step S 126 ), the control unit  7  controls the image processing unit  2  so that the transfer or the dividing operation is made (step S 127 ).  
      According to these examples, the user could have enough time to interpret images based on the medical image information.  
      Returning to  FIG. 4 , after the divining operation and preparation of the predetermined personal information and the image information in step S 4 , the medical image information divining unit  22  issues personal information ID for the predetermined personal information and image information ID for the image information (step S 5 ). The medical image information dividing unit  22  then gives the personal information ID to the predetermined personal information and prepares the ID-given predetermined personal information. Also, the medical image information dividing unit  22  then gives the image information ID to the image information and prepares the ID-given image information (step S 6 ). The ID-given predetermined personal information is stored in the personal information storage unit  32  (step S 7 ). The ID-given image information is stored in the image information storage unit  31  (step S 8 ). After the storage in steps S 7  and S 8 , the medical image information is deleted from the medical image information storage unit  21  so that the user cannot obtain the medical image information without the decryption key (step S 9 ).  
      For the user&#39;s image interpretation work, the time measurement examples have been described with reference to FIGS.  5  to  7 . Instead of applying the time measurement examples to the determination of whether to proceed to the dividing operation, similar examples may be applicable to the above delete operation instep S 9 . For example, step S 105  in  FIG. 5 , S 114  in  FIG. 6 , or S 127  in  FIG. 7  may be replaced by step S 131  shown in  FIG. 8 . That is, the delete operation in step S 9  may be conducted only after an elapse of the predetermined time by the time measurement.  
      The medical image information dividing unit  22  also prepares a table of a relationship between the predetermined personal information and the image information. First, a preliminary table is prepared, which includes the personal information ID, the image information ID, and an examination date (step S 10 ). Next, the medical image information dividing unit  22  prepares the table by combining the unique information to the preliminary table as shown in  FIG. 3A  (step S 11 ).  
      The table is transferred to and encrypted by the table encryption unit  51  (step S 12 ). As described before, the table encryption unit  51  may use the decryption key received from the IC card  81  through the IC card reader  61  or the public key stored in the table encryption unit  51  or other unit in the medical image storage unit  10 . When the encryption key is not stored as the public key, an input of the encryption key may be required through a requirement display in the display unit  43 . In response to the requirement display, the user may insert the IC card  81  into the IC card reader  61 . To be precise, the user may ask the patient to insert the IC card  81  into the IC card reader  61 . Even if the public key is not used as the encryption key, the table maybe encrypted, by reading the encryption key from the IC card  81  in advance. As shown in  FIG. 3B , only the personal information ID and the image information ID may be encrypted in the table encryption unit  51 . The time measurement examples for the user&#39;s image interpretation may still alternatively be applied to the encryption operation in step S 12 . For example, step S 105  in  FIG. 5 , S 114  in  FIG. 6 , or S 127  in  FIG. 7  may be replaced by step S 141  shown in  FIG. 9 . That is, the encryption operation in step S 12  may be conducted only after an elapse of the predetermined time by the time measurement. The encrypted table is stored in the table storage unit  52 . The storing operation may be completed by this storage.  
      Outputting operations of the medical image information will be described with reference to a flowchart shown in  FIG. 10 .  FIG. 10  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus  10  according to the first embodiment. Since the medical image information has been deleted from the medical image storage apparatus  10 , the user needs to decrypt the encrypted table so that the medical image information is reproduced based on the table if the user needs to obtain the medical image information.  
      The user may input an instruction to start obtaining the medical image information through the operation unit  6 . In order to obtain and output the medical image information except for the time of the image interpretation which may have been completed before the encryption, the user then needs to ask the patient to insert the IC card  81  into the IC card reader  61 . The user may first input unique information of the patient from the operation unit  6 . Or when the unique information is stored in the IC card  61 , the user may ask the patient to insert the IC card  81  into the IC card reader  61  so that the unique information is read from the IC card  81  (step S 21 ). The unique information through the operation unit  6  is transferred to the table decryption unit  53 . The table decryption unit  53  then compares the transferred unique information to unique information included in the encrypted table stored in the table storage unit  52  since the unique information included in the table is not encrypted as shown in  FIG. 3B . The table decryption unit  53  retrieves one or more encrypted tables including unique information identical to or corresponding to the transferred unique information (step S 22 ). After the retrieval, an input of the decryption key is required through the requirement display in the display unit  43  (step S 23 ).  
      In response to the insertion of the IC card  81  into the IC card reader  61 , the IC card reader  61  reads the decryption key from the IC card  81  and the table decryption unit  53  receives the decryption key (step S 24 ). As described before, the decryption key may be the private key of the patient. The table decryption unit  53  then decrypts the one or more encrypted tables with the decryption key and obtains one or more tables (step S 25 ). When there is only one table obtained in step S 25  (step S 26 ), the table is transferred to the medical image information preparation unit  41  (step S 27 ). When there are two or more tables obtained in step S 25 , the examination dates included in the respective tables are displayed as a list of examination dates in the display unit  43  (step S 28 ). When the user designates one of the listed examination dates, using the operation unit  6  (step S 29 ), the table corresponding to the designated examination date is transferred to the medical image information preparation unit  41  (step S 30 ).  
      The medical image information preparation unit  41  retrieves the ID-given predetermined personal information stored in the personal information storage unit  32  in accordance with the personal information ID included in the transferred table and the ID-given image information stored in the image information storage unit  32  in accordance with the image information ID included in the transferred table (step S 31 ). The medical image information preparation unit  41  obtains the predetermined personal information given the ID identical to or corresponding to the personal information ID included in the transferred table. Similarly, the medical image information preparation unit  41  obtains the image information given the ID identical to or corresponding to the image information ID included in the transferred table. By combining the personal information and the image information, the medical image information preparation unit  41  prepares to reproduce the medical image information (step S 32 ). The medical image information is transferred to the display unit  43  (step S 33 ) and displayed in the display unit  43  (step S 34 ).  
      If the user needs to use the image data for the purpose of researching images resulting from the image data, the image information including the image data can be utilized. Also, when a maintenance service staff needs to use the image data to refer to images based on the image data during the maintenance service, the image information can be utilized. For any other purpose, which does not directly relate to medical practices for the patient associated with the image data, the image information stored in the image information storage unit  31  can be utilized.  
       FIG. 11  is a flowchart showing an exemplary flow of outputting the image information in the medical image storage apparatus  10  according to the first embodiment. When the user, the maintenance service staff, or other person who needs to obtain images (hereinafter collectively referred to as an operator) desires to obtain the images, the operator inputs retrieval conditions from the operation unit  6  (step S 41 ). The retrieval conditions may be one or more of a type of a medical imaging apparatus, an imaging condition, imaged part information, and the like. Selectable items corresponding to these retrieval conditions may be displayed in the display unit  43  in response to a predetermined operation through the operation unit  6 . In this case, the operator may only need to select desired conditions with respect to the displayed items.  
      In response to the input or selection, the image information retrieval unit  42  retrieves the image information stored in the image information storage unit  31  based on the retrieval conditions (step S 42 ). The retrieved image information is transferred to the display unit  43  (step S 43 ). The image information is displayed as images, a type of a medical imaging apparatus, an imaging condition, imaged part information, and the like while no personal information is displayed in the display unit  43  (step S 44 ).  
      The personal information is stored separately from the image information and cannot be matched with the image information without decrypting the encrypted table. The encrypted table can be decrypted only with the decryption key. The decryption key is administered by the patient. Therefore, the personal information is secured from the operator when the images are required for the purpose which does not directly relate to medical practices for the patient associated with the images. On the other hand, when the user needs to display the medical image information including the personal information, the user can display the medical image information, using the decryption key administered by the patient. In other words, for the patient, the personal information included in the medical image information cannot be referred to even by the user without the patient&#39;s administering decryption key. This may mean that the personal information is referred to only in front of the patient.  
      In  FIG. 1 , the operation unit  6  includes the IC card reader  61 . Accordingly, the user may need to borrow the IC card  81  from the patient and bring it to the medical image storage apparatus  10 , which is typically provided where the patient is not permitted to enter. Otherwise, the patient may be asked to come to the medical image storage unit  10  and insert his/her IC card  81  into the IC card reader  61 . These may not be practical. One possible application may be a use of the IC card reader  61  remotely connected to a main body of the medical image storage unit  10  through the hospital LAN or a direct communication line. The IC card reader  61  is still operative as part of the operation unit  6  while the IC card reader  81  may be provided in a consultation room where the patient is usually consulted by the user.  
      Another practical way of receiving information stored, for example, in the IC card  81  is shown in  FIG. 12 . The operation unit  6  includes a second receiving unit  62  instead of the IC card reader  61  shown in  FIG. 1 . The second receiving unit  62  is connected to an external IC card reader  11  through the hospital LAN. The external IC card reader  11  may be directly connected to the hospital LAN or through a medical image display apparatus such as, for example, a workstation. The external IC card reader  11  may be provided in the consultation room. The second receiving unit  62  receives the unique information, the encryption key, and/or the decryption key read from the IC card  81  by the external IC card reader  11 .  
      Also in  FIG. 12 , the output unit  4  includes a transmitting unit  44  instead of the display unit  43  shown in  FIG. 1 . The medical image information prepared by the medical image information preparation unit  41  is transmitted to an external medical image display apparatus  12 , for example, through the hospital LAN (omitted in  FIG. 12 ). Similarly, the image information retrieved by the image information retrieval unit  42  is transmitted to the external medical image display apparatus  12 . The external medical image display apparatus  12  may be the same apparatus as that connected to the external IC card reader  11  so that the external medical image display apparatus  12  can request the medical image information or the image information and receive the requested information.  
      The rest of the configuration of the medical image storage apparatus  10  may be similar to the corresponding units shown in  FIG. 1  and therefore, the detail explanation is omitted herein.  
     Second Embodiment  
      In the second embodiment, the table is not encrypted but still made unavailable to the user and the operator.  FIG. 13  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the second embodiment. As shown in  FIG. 13 , a medical image storage apparatus  20  does not include the table processing unit. The operation unit  6  also does not include the IC card reader  61  but an IC card reader/writer  63 . Other configuration of the medical image storage apparatus  20  may be similar to those included in the medical image storage apparatus  10  shown in  FIG. 1 . Therefore, the detail explanation of the similar configuration is omitted herein.  
      The IC card reader/writer  63  may read the unique information from the IC card  81 . Further, the IC card reader/writer  63  writes the table to the IC card  81  and reads the table from the IC card  81 . The IC card reader/writer  63  may correspond to the ‘first unit configured to make the table unavailable’ and also to the ‘second unit configured to recapture the table’.  
       FIG. 14  is a flowchart showing an exemplary flow of writing the table to the IC card  81  according to the second embodiment. The table is prepared in the medical image information divining unit  22  in accordance with steps S 1  to S 10  shown in  FIG. 4  (step S 51 ). The table is transferred to the IC card reader/writer  63  and written to the IC card  81  (step S 52 ). Therefore, the medical image information cannot be reproduced without the IC card  81 . Since the table concerning a patient is stored in the IC card  81  kept and administered by the patient, the table may not include the unique information as shown in  FIG. 15 .  
       FIG. 16  is a flowchart showing an exemplary flow of outputting the medical image information according to the second embodiment. The user may input an instruction to start obtaining the medical image information through the operation unit  6 . In order to obtain and output the medical image information except for the time of the image interpretation which may have been completed before the encryption, the user then needs to ask the patient to insert the IC card  81  into the IC card reader/writer  63 . The patient inserts the IC card  81  to the IC card reader/writer  63  and the IC card reader/writer  63  reads the table from the IC card  81  (step S 61 ). It may not be necessary for the user to input the unique information of the patient. After the table read from the IC card  81  is transferred to the medical image information preparation unit  41 , the medical image information may be displayed in the display unit  43  in accordance with steps S 26  to S 34  shown in  FIG. 10  (step S 62 ).  
      As a modification to the operation unit  6 , the operation unit  6  may include a disk drive unit  64  as shown in  FIG. 17 . The disk drive unit  64  may correspond to the ‘first unit’ and the ‘second unit’.  FIG. 17  is a block diagram showing a modified exemplary configuration of the medical image storage apparatus according to the second embodiment. The disk drive unit  64  may write to and read from a magneto-optic disk (MO)  84 , a digital versatile disk (DVD)  85 , or a compact disk recordable (CD-R)  86 . The MO  84 , the DVD  85 , and the CD-R  86  are other examples of the external memory medium  8  although applicable recordable disks are not limited to these examples.  
      As shown in  FIG. 18 , the medical image storage apparatus  20  may not include the IC card reader/writer  63  but a transceiver unit  65 . The transceiver unit  65  may correspond to the ‘first unit’ and the ‘second unit’, and is connected to an external IC card reader/writer  13  through the hospital LAN. The external IC card reader/writer  13  may be directly connected to the hospital LAN or through a medical image display apparatus such as, for example, a workstation. The external IC card reader/writer  13  maybe provided in the consultation room. The transceiver unit  65  transmits the table transferred from the medical image information dividing unit  22  to the external IC card reader/writer  13 . The transceiver unit  65  also receives the table read from the IC card  81  from the external IC card reader/writer  13 .  
      Also in  FIG. 18 , the output unit  4  includes the transmitting unit  44  instead of the display unit. The medical image information prepared by the medical image information preparation unit  41  is transmitted to the external medical image display apparatus  12 , for example, through the hospital LAN (omitted in  FIG. 18 ). Similarly, the image information retrieved by the image information retrieval unit  42  is transmitted to the external medical image display apparatus  12 . The external medical image display apparatus  12  may be the same apparatus as that connected to the external IC card reader/writer  13  so that the medical image display apparatus  12  can request the medical image information or the image information and receive the requested information.  
     Third Embodiment  
      The unique information has been described for distinguishing the patient in the first embodiment. The unique information may alternatively be used to distinguish the user.  FIG. 19  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the third embodiment. As shown in  FIG. 19 , the operation unit  6  may not include the IC card reader but a medical image storage apparatus  30  includes a key generation unit  66 , an authentication unit  67 , a user ID (ID: identification information) storage unit  68 , a key storage unit  69 , and a key input/output unit  70 .  
      The key generation unit  66  generates an encryption key and a decryption key for each user. The encryption key and the decryption key may be the same one key. The authentication unit  67  authenticates the user who is allowed to login the medical image storage apparatus  30  by authentication information such as, for example, a user ID and a password input from the operation unit  6 . In response to the authentication, the user logins the medical image storage apparatus  30 . The user ID storage unit  68  stores the user ID authenticated by the authentication unit  67 . That is, the user ID stored in the user ID storage unit  68  pertains to the user currently logging in the medical image storage apparatus  30 . The key storage unit  69  stores the encryption key and the decryption key in relationship to the user ID with respect to one or more users. The key input/output unit  70  obtains the user ID stored in the user ID storage unit  68  and retrieves from the key storage unit  69  the encryption key or the decryption key which corresponds to the user ID. The key input/output unit  70  then outputs the encryption key or the decryption key to the control unit  7  so that the encryption key is transferred to the table encryption unit  51  when the encryption is required and the decryption key is transferred to the table decryption unit  53  when the decryption is required. The rest of the configuration of the medical image storage apparatus  30  may be similar to the corresponding units shown in  FIG. 1  and therefore, the detail explanation is omitted herein.  
      In this embodiment, the unique information included in the table is the user ID as shown in  FIG. 20  and the user ID is not encrypted when the table is encrypted with the encryption key in the table encryption unit  51  as similar to  FIG. 3B .  
      Outputting operations of the medical image information will be described with reference to a flowchart shown in  FIG. 21 .  FIG. 21  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus  30  according to the third embodiment.  
      The user who needs to obtain the medical image information with respect to his/her patient inputs the authentication information from the operation unit  6  (step S 71 ). The authentication information is transferred to the authentication unit  67  and authenticated by the authentication unit  67  (step S 72 ). If the authentication succeeds (step S 73 ), the user ID of the user corresponding to or included in the authentication information is stored as the user ID of the current user in the user ID storage unit  68  (step S 74 ). The user is allowed to login the medical image storage apparatus  30  and may start to use the medical image storage apparatus  30 .  
      The user may make a request of obtaining the medical image information through the operation unit  6  (step S 75 ). In response to the request, the control unit  7  obtains the user ID from the user ID storage unit  68  (step S 76 ) and transfers the user ID to the table decryption unit  53 . The table decryption unit  53  retrieves one or more encrypted tables including user ID identical to the transferred user ID (step S 77 ). The control unit  7  also controls the key input/output unit  70  so as to retrieve from the key storage unit  69  the decryption key corresponding to the user ID stored in the user ID storage unit  68  (step S 78 ). After the retrieval, the decryption key is transferred to the table decryption unit  53 , and the medical image information is displayed in the display unit  43  in accordance with steps S 25  to S 34  shown in  FIG. 10  (step S 79 ).  
      According to the third embodiment, the user can obtain the medical image information with respect to only the user&#39;s patient. Therefore, although the patient&#39;s personal information included in the medical image information is not always referred in front of the patient, the patient may be secured that his/her medical image information is referred to only by the user or cannot be referred to at least without through the user&#39;s operation.  
      The input of the authentication information and the request may be made from an external input unit as shown in  FIG. 22 . The operation unit  6  includes the second receiving unit  62 . The second receiving unit  62  is connected to an external input unit  14 , for example, through the hospital LAN. The external input unit  14  may be connected to the hospital LAN directly or as part of a medical image display apparatus such as, for example, a workstation. The external input unit  14  may be provided in the consultation room. The second receiving unit  62  receives the authentication information and the request input from the external input unit  14 .  
      Also in  FIG. 22 , the output unit  4  includes the transmitting unit  44  instead of the display unit shown in  FIG. 19 . The medical image information prepared by the medical image information preparation unit  41  is transmitted to the external medical image display apparatus  12 , for example, through the hospital LAN (omitted in  FIG. 22 ). Similarly, the image information retrieved by the image information retrieval unit  42  is transmitted to the external medical image display apparatus  12 . The external medical image display apparatus  12  may be the same apparatus as that incorporating the external input unit  14  so that the medical image display apparatus  12  can request the medical image information or the image information and receive the requested information.  
      The rest of the configuration of the medical image storage apparatus  30  may be similar to the corresponding units shown in  FIG. 19  and therefore, the detail explanation is omitted herein.  
      In the third embodiment, the user ID has been used as the unique information. Information distinguishing a consultation department provided in the hospital such as, for example, internal medicine or surgery may be used as an alternative example of the unique information.  
     Fourth Embodiment  
      In the first to third embodiments, the medical image information has been received from the X-ray CT apparatus and divided into the personal information and the image information in the medical image information dividing unit. According to the fourth embodiment, the personal information may be obtained separately from the medical image information so that it is not necessary to divide the medical image information.  
       FIG. 23  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the fourth embodiment. As shown in  FIG. 23 , a medical image storage apparatus  40  may be connected to a hospital information system and/or a radiology information system (hereinafter referred to as a HIS/RIS)  15 , for example, through the hospital LAN. The medical image storage apparatus  40  may also be connected to one or more of an examination selection unit  16 , a reservation information input unit  17 , and an examination information input unit  18 . The examination selection unit  16 , the reservation information input unit  17 , and the examination information input unit  18  maybe provided in one or more external apparatuses, which are connected to the receiving unit  1 , for example, through the hospital LAN. The image processing unit  2  may not include the medical image information dividing unit but a reservation information storage unit  23 , a personal information preparation and storage unit  24 , and a table preparation unit  25  as well as the medical image information storage unit  21 .  
      The receiving unit  1  receives the medical image information from the X-ray CT apparatus  80  as described in the first embodiment. The received medical image information is transferred to the medical image information storage unit  21 . The medical image information storage unit  21  removes predetermined personal information included in the medical image information in accordance with a predetermined rule. Accordingly, the image information is prepared. Dummy information may be incorporated into the image information instead of the removed predetermined personal information.  
      The receiving unit  1  also receives examination reservation information from the HIS/RIS  15 . The examination reservation information concerning a forthcoming imaging examination of the patient is typically input to the HIS/RIS  15  so as to reserve the imaging examination for the patient. The examination reservation information usually includes various types of information of a forthcoming examination and a patient, so may include personal information of the patient. The reservation information storage unit  23  stores the examination reservation information received by the receiving unit  1 . The personal information preparation and storage unit  24  extracts and prepares predetermined personal information from the examination reservation information stored in the reservation information storage unit  23  in accordance with the predetermined rule. The prepared predetermined personal information is stored in the personal information preparation and storage unit  24 .  
      The receiving unit  1  may also receive examination selection information from the examination selection unit  16 . The examination selection information may be transferred to the reservation information storage unit  23  so that the personal information preparation and storage unit  24  conducts the above operation with respect to the examination reservation information selected based on the examination selection information. The receiving unit  1  may further receive the examination reservation information from the reservation information input unit  17 . The examination reservation information received from the reservation information input unit  17  may also be stored in the reservation information storage unit  23  and treated in a similar manner to those received from the HIS/RIS  15 . Examination information received from the examination information input unit  18  may be transferred to the personal information preparation and storage unit  24 . The personal information preparation and storage unit  24  may also or alternatively extract the predetermined personal information from the examination information received from the examination information input unit  18  if necessary although the personal information preparation and storage unit  24  extracts the predetermined personal information from the examination reservation information as described above. One or more of the examination reservation information, the examination selection information, and the examination information may correspond to ‘examination-relating information’.  
      The table preparation unit  25  issues the personal information ID and the image information ID. The personal information ID is given to the predetermined personal information stored in the personal information preparation and storage unit  24 . The image information ID is given to the image information stored in the medical image information storage unit  21 . The table preparation unit  25  also prepares a table of a relationship between the predetermined personal information and the image information in a manner similar to that described in the first embodiment. The table is transferred to the table encryption unit  51 .  
      The rest of the configuration of the medical image storage apparatus  40  may be similar to the corresponding units shown in  FIG. 1  and therefore, the detail explanation is omitted herein.  
      Storing operations of the predetermined personal information and the image information will be described with reference to a flowchart shown in  FIG. 24 .  FIG. 24  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus  40  according to the fourth embodiment.  
      The storing operation may start similarly to step S 1  in  FIG. 4 . However, the examination reservation information may be received from the HIS/RIS  15  by the receiving unit  1  in advance of receiving the medical image information from the X-ray CT apparatus  80 . When the receiving unit  1  has received the examination reservation information from the HIS/RIS  15  and/or the reservation information input unit  17 , the examination reservation information is transferred to the reservation information storage unit  23 . The examination reservation information is stored in the reservation information storage unit  23 , for example, until the reserved examination is completed or the medical image information is received by the receiving unit  1  (step S 81 ). Also, when the receiving unit  1  has received the medical image information from the X-ray CT apparatus  80 , the medical image information is transferred to and stored in the medical image information storage unit  21  (step S 82 ).  
      The examination reservation information is transferred to the personal information preparation and storage unit  24 , for example, in response that the medical image information has been received by the receiving unit  1 . When the receiving unit  1  has received the examination information from the examination information input unit  18 , the examination information is also stored in the personal information preparation and storage unit  24 . The personal information preparation and storage unit  24  extracts predetermined personal information, which is included in the examination reservation information and the examination information and is appropriate to be combined with the image information. The predetermined personal information may be prepared as a result of the extraction (step S 83 ) and stored in the personal information preparation and storage unit  24  (step S 84 ).  
      In the medical image information storage unit  21 , the predetermined personal information is removed from the medical image information so that the image information is prepared (step S 85 ). The prepared image information is stored in the medical image information storage unit  21  (step S 86 ).  
      Although the table is prepared by the table preparation unit  25  and also the personal information ID and the image information ID are issued by the table preparation unit  25  as described above, the table is encrypted and the medical image information is made unavailable in a manner similar to those in steps S 5  to S 13  shown in  FIG. 4  (step S 87 ).  
      Outputting operations of the medical image information may be accomplished in a manner shown in  FIG. 10 .  
     Fifth Embodiment  
      The patient&#39;s personal information may be secured that his/her medical image information is obtained only by limited one or more users or cannot be obtained at least without through these users&#39; operation according to the fifth embodiment.  
       FIG. 25  is a block diagram showing an exemplary configuration of a medical image storage apparatus according to the fifth embodiment. A medical image storage apparatus  50  does not include the table processing unit but the authentication unit  67 , the user ID storage unit  68 , a table storage unit  71 , a table output unit  72 , a user&#39;s authority storage unit  73 , and a table use permission determining unit  74 .  
      The authentication unit  67  and the user ID storage unit  68  are operative in a manner as described in the third embodiment. The table storage unit  71  stores the table prepared in the medical image information dividing unit  22 . The table output unit  72  outputs the table stored in the table storage unit  71  to the medical image information preparation unit  41  in accordance with an instruction from the table use permission determining unit  74 . The user&#39;s authority storage unit  73  stores the second table showing if the user is permitted to use the table. For example, the second table may show that users A and C (or user IDs A and C) are permitted to use the table but the user B (or user ID B) cannot with respect to a specific patient (or specific unique information). The second table may include such information with respect to one or more patients. The user&#39;s authority storage unit  73  may alternatively store the second table showing with respect to which unique information the user is permitted to use the table. For example, the second table may show that a user A (or user ID A) is permitted to use the table concerning patients A, B, and C (or unique information A, B, and C) while a user B (or user ID B) is permitted to use the table concerning the patients A and B (or the unique information A and B). And the second table may also show that a user C (or user ID C) is not permitted to use any table or may not include information of the user C (or the user ID C), which means the user C is not a permitted user of any table. The table use permission determining unit  74  determines whether or not the user who logged in the medical image storage unit  50  is permitted to use one or more tables based on the second table stored in the user&#39;s authority storage unit  73 .  
      The rest of the configuration of the medical image storage apparatus  50  may be similar to the corresponding units shown in  FIG. 1  and therefore, the detail explanation is omitted herein.  
       FIG. 26  is a flowchart showing an exemplary flow of storing the medical image information in the medical image storage apparatus  50  according to the fifth embodiment. In storing operations of the medical image information, the table may be prepared in accordance with steps S 1  to S 10  shown in  FIG. 4  (step S 88 ). The table is stored in the table storage unit  71  (step S 89 ). This table is made unavailable by the user&#39;s authority storage unit  73 , the table use permission determining unit  74 , and the table output unit  72 . In other words, the user&#39;s authority storage unit  73 , the table use permission determining unit  74 , and the table output unit  72  may collectively correspond to the ‘first unit’ and the ‘second unit’.  
      Outputting operations of the medical image information will be described with reference to a flowchart shown in  FIG. 27 .  FIG. 27  is a flowchart showing an exemplary flow of outputting the medical image information in the medical image storage apparatus  50  according to the fifth embodiment.  
      The user who needs to obtain the medical image information with respect to a specific patient inputs the authentication information from the operation unit  6  (step S 91 ). The authentication information is transferred to and authenticated by the authentication unit  67  (step S 92 ). If the authentication succeeds (step S 93 ), the user ID of the user corresponding to or included in the authentication information is stored as the user ID of the current user in the user ID storage unit  68  (step S 94 ). The user is allowed to login the medical image storage apparatus  50  and may start to use the medical image storage apparatus  50 .  
      The user may input unique information concerning the specific patient from the operation unit  6  (step S 95 ). The unique information may be transferred to the table use permission determining unit  74 . The table use permission determining unit  74  obtains the current user ID from the user ID storage unit  68  and, for example, retrieves information of the second table concerning the obtained user ID from the user&#39;s authority storage unit  73  (step S 96 ). The table use permission determining unit  74  then determines whether the current user ID is permitted to use table(s) of the transferred unique information or not (step S 97 ). When the table use permission determining unit  74  determines that the current user ID is permitted to use the table(s) of the transferred unique information, the table output unit  72  outputs one or more tables of the unique information to the medical image information preparation unit  41  (step S 98 ). The medical image information may be displayed in accordance with steps S 26  to S 34  shown in  FIG. 10  (step S 99 ). If the table use permission determining unit  74  does not determines that the current user ID is permitted to use the table(s) of the transferred unique information in step S 97 , the control unit  7  controls the output unit  4  so that the display unit  43  displays information of an error that the user is not permitted to obtain the medical image information of the patient concerning the input unique information (step S 100 ).  
     Sixth Embodiment  
      The feature of the medical image storage apparatus described in the first to fifth embodiments may also be implemented in a medical imaging apparatus such as one mentioned in the first embodiment. Two examples will be described below although any other one or more embodiments described above or their combination may also be applied to the medical imaging apparatus.  
       FIG. 28  is a block diagram showing an exemplary configuration of a medical imaging apparatus according to the sixth embodiment. A medical imaging apparatus  60  may include an imaging unit  75 , the image processing unit  2 , the storage unit  3 , the output unit  4 , the table processing unit  5 , the operation unit  6 , and the control unit  7 . The external memory medium  8  may be used for the operation unit  6 .  
      The imaging unit  75  generates medical image information and may include, for example, an X-ray tube, an X-ray detector, a data acquisition system, a reconstruction section, an information preparation section, and the like when the medical imaging apparatus  60  is an X-ray CT apparatus. The X-ray tube generates X-ray towards a patient and the X-ray detector detects X-ray information resulting from the generated X-ray. The detected X-ray information is acquired by the data acquisition system and is reconstructed to produce image data by the reconstruction section. The information preparation section prepares medical image information by combining the image data and its accompanying information. The accompanying information may be obtained from the operation unit  6  or from an external apparatus (not shown in  FIG. 28 ), for example, through the hospital LAN. The medical image information is transferred to the image processing unit  2 .  
      The image processing unit  2 , the storage unit  3 , the output unit  4 , the table processing unit  5 , the operation unit  6 , and the control unit  7  may be operative in a manner similar to the corresponding units in  FIG. 1 , and therefore, the detail explanation is omitted herein.  
      A modification of the medical imaging unit  60  will be described with reference to  FIG. 29 .  FIG. 29  is a block diagram showing a modified exemplary configuration of the medical imaging apparatus  60  according to the sixth embodiment. As shown in  FIG. 29 , the medical imaging apparatus  60  include the receiving unit  1 , which may be connected to the HIS/RIS  15 , for example, through the hospital LAN. The image processing unit  2  may not include the medical image information dividing unit but includes the reservation information storage unit  23 , the personal information preparation and storage unit  24 , and the table preparation unit  25  as well as the medical image information storage unit  21 .  
      The receiving unit  1  receives examination reservation information from the HIS/RIS  15  and the received examination reservation information is stored in the reservation information storage unit  23  as described in the fourth embodiment. Also as described in the fourth embodiment, the personal information preparation and storage unit  24  extracts, prepares, and stores predetermined personal information from the examination reservation information stored in the reservation information storage unit  23 . The table preparation unit  25  is operative in a manner similar to that described in the fourth embodiment.  
      The operation unit  6  includes an examination selection unit  76 , a reservation information input unit  77 , and an examination information input unit  78  as well as the IC card reader  61 . The examination selection unit  76  maybe used to select an examination from a listed plurality of reserved examinations so that the medical imaging apparatus  60  conducts imaging with respect to the selected examination. The personal information preparation and storage unit  24  may conduct the described operation with respect to the examination reservation information concerning the selected examination. The reservation information input unit  77  is provided to input the examination reservation information to be stored in the reservation information storage unit  23 , but may not be used so often. The examination information input unit  78  may be used to input the examination information. The examination information input from the examination information input unit  78  is transferred to the personal information preparation and storage unit  24 . The personal information preparation and storage unit  24  may also or alternatively extract the predetermined personal information from the transferred examination information if necessary although the personal information preparation and storage unit  24  extracts the predetermined personal information from the examination reservation information as described above.  
      The imaging unit  75  is operative as described with reference to  FIG. 28 . The medical image information generated from the imaging unit  75 , however, may not include personal information. Therefore, the medical image information storage unit  21  stores the medical image information as the image information.  
      The rest of the configuration of the medical imaging apparatus  60  may be similar to the corresponding units shown in  FIG. 28  and therefore, the detail explanation is omitted herein. In  FIG. 29 , the connection is omitted between the control unit  7  and other units.  
     Seventh Embodiment  
       FIG. 30  is an illustration showing an example of a medical image system according to the seventh embodiment. The medical image system may include a medical imaging apparatus  310 , a medical image storage apparatus  320 , and a medical image display apparatus  330 , which may be connected to one another through a hospital LAN. The medical image display apparatus  330  may be connected to an IC card reader  340 . The IC card reader  340  reads information stored in an IC card  350 .  
      The medical imaging apparatus  310  may be any type of medical imaging apparatus mentioned in the first embodiment. The medical imaging apparatus  310  may have features of, but which are not limited to, imaging  311 , table preparation  312 , table encryption  313 , and transmission of encrypted table, ID-given image information, and ID-given predetermined personal information  314 . The imaging feature  311  may be implemented in a unit such as, for example, the imaging unit  75 . The table preparation feature  312  may be implemented in a unit such as, for example, the medical image information dividing unit  22 . The table encryption feature  313  may be implemented in a unit such as, for example, the table encryption unit  51 . The transmission feature  314  may be implemented in a unit such as, for example, a unit like the transmitting unit  44  if the transmitting unit  44  is provided in the medical imaging apparatus  60  in the sixth embodiment.  
      The medical image storage apparatus  320  may be a filing server and have features of, but which are not limited to, encryption key storage  321 , storage of the encrypted table, the ID-given image information, and the ID-given personal information  322 , table decryption  323 , medical image information preparation  324 , image information retrieval  325 , and transmission of the medical image information or the image information  326 . The encryption key storage feature  321  may be implemented in a unit such as, for example, the control unit  7 . The storage feature  322  may be implemented in units such as, for example, the storage unit  3  and the table storage unit  52 . The table decryption feature  323  may be implemented in a unit such as, for example, the table decryption unit  53 . The medical image information preparation feature  324  may be implemented in a unit such as, for example, the medical image information preparation unit  41 . The image information retrieval feature  325  may be implemented in a unit such as, for example, the image information retrieval unit  42 . The transmission feature  326  may be implemented in a unit such as, for example, the transmitting unit  44 .  
      The medical image display apparatus  330  may be a workstation and used, for example, to interpret images in an image interpretation room, to observe images in a consultation room, or to research images in a conference room. The medical image display unit  330  may have features of, which are not limited to, decryption key transmission  331 , medical image information request  332 , image information request  333 , and display of the medical image information or the image information  334 . The decryption key transmission feature  331  may be implemented, for example, in a transceiver unit. The medical image information request feature  332  and the image information request feature  333  maybe implemented, for example, in an input unit and the transceiver unit. The display feature  334  may be implemented, for example, in a display unit.  
      The IC card  350  may include a decryption key  351  corresponding to the encryption key. When the encryption key stored in the medical image storage apparatus  320  is a public key of a patient, the decryption key  351  is a private key corresponding to the public key. The IC card  350  may be kept and administered by the patient.  
      A communication flow among the medical imaging apparatus  310 , the medical image storage apparatus  320 , the medical image display apparatus  330 , the IC card reader  340 , and the IC card  350  will be described briefly below. When the medical image information is generated by the imaging feature  311 , predetermined personal information and image information are prepared based on the medical image information, and also a table of a relationship between the predetermined personal information and the image information is prepared by the table preparation feature  312 . The predetermined personal information and the image information are given IDs, respectively. The given IDs are included in the table. The table is encrypted with the encryption key by the table encryption feature  313 . The encryption key may be obtained from the medical image storage apparatus  320 . The encrypted table is transmitted to the medical image storage apparatus  320  by the transmission feature  314 . Also, the ID-given personal information and the ID-given image information are transmitted to the medical image storage apparatus  320  by the transmission feature  314 .  
      The transmitted encrypted table, the ID-given personal information, and the ID-given image information are received and stored in the medical image storage apparatus  320  by the storage feature  322 .  
      When a user desires to obtain the medical image information of the patient, the user requests the medical image information and the request is transmitted from the medical image display apparatus  330  to the medical image storage apparatus  320  by the medical image information request feature  332 . The user also asks the patient to insert his/her IC card  350  into the IC card reader  340 . In response to the insertion, the IC card reader  340  reads the decryption key  351  from the IC card  350 . The decryption key  350  is provided to the medical image display apparatus  330  and transmitted to the medical image storage apparatus  320  by the decryption key transmission feature  331 . The medical image storage apparatus  320  decrypts the encrypted table with the decryption key  351  by the table decryption feature  323 . Based on the decrypted table, the medical image information is prepared and reproduced by the medical image information preparation feature  324 . The medical image information is transmitted to the medical image display apparatus  330  by the transmission feature  326 . In the medical image display apparatus  330 , the medical image information is displayed by the display feature  334 .  
      When the operator requests the image information by the image information request feature  333 , the request is transmitted from the medical image display apparatus  330  to the medical image storage apparatus  320  by the image information request feature  333 . In the medical image storage apparatus  320 , the image information is retrieved by the image information retrieval feature  325 . The image information is transmitted to the medical image display apparatus  330  by the transmission feature  326 . In the medical image display apparatus  330 , the image information is displayed by the display feature  334 .  
      As described above, the encryption and the decryption may not always be implemented in the same apparatus. Also the image request and display may not be implemented in the apparatus which encrypts and/or decrypts the table. The features described in one or more of the embodiments described above may be implemented in different apparatuses and accomplished in totality within a predetermined medical image system. The seventh embodiment described with reference to  FIG. 30  is only one example of such a system.  
      Further, the medical image system may a system as shown in  FIG. 31 .  FIG. 31  is an illustration showing another example of the medical image system according to the seventh embodiment. As shown in  FIG. 31 , the medical image storage apparatus  320  may include an encrypted table transmission feature  327  and a decrypted table reception feature  328  instead of the table decryption feature  323 . The medical image display apparatus  330  may include a table decryption feature  335  and a decrypted table transmission feature  336  instead of the decryption key transmission feature  331 .  
      In response to the request of the medical image information by the medical image information request feature  332  in the medical image display apparatus  330 , the encrypted table is transmitted from the medical image storage apparatus  320  by the encrypted table transmission feature  327 . The decryption key  350  read by the IC card reader  340  is provided to the medical image display apparatus  330  and the encrypted table is decrypted with the decryption key by the table decryption feature  335 . The decrypted table is transmitted to the medical image storage apparatus  330  by the decrypted table transmission feature  336 . The decrypted table is received by the decrypted table reception feature  328 . Based on the decrypted table, the medical image information is prepared and reproduced by the medical image information preparation feature  324 . The medical image information is transmitted to the medical image display apparatus  330  by the transmission feature  326 . In the medical image display apparatus  330 , the medical image information is displayed by the display feature  334 .  
      When the decrypted table is transmitted from the medical image display apparatus  330  to the medical image storage apparatus  320 , the decrypted table may be transmitted through a network secured by, for example, SSL (Secure Socket Layer) or IP Sec.  
      In the above embodiments in which the IC card  81  is used, the IC card  81  may be operative as part of one of the apparatuses  10  to  60 , and  330  and include a memory  810  and a decryption unit (or feature)  820 , as shown in  FIG. 32 . The memory  810  stores the decryption key. The IC card  81  may receive the encrypted table and the received table is decrypted by the decryption unit  820 . The decrypted table is provided to the one apparatus. According to this example, the decryption key itself is not transmitted through a network so as to be secured. The decrypted table may be sent to the apparatus through a network secured by, for example, SSL (Secure Socket Layer) or IP Sec.  
      Also one or more of the first to seventh embodiments may be combined as another embodiment.  
      The embodiments of the present invention described above are examples described only for making it easier to understand the present invention, and are not described for the limitation of the present invention. Consequently, each component and element disclosed in the embodiments of the present invention may be redesigned or modified to its equivalent within a scope of the present invention. Furthermore, any possible combination of such components and elements may be included in a scope of the present invention as long as an advantage similar to those obtained according to the above disclosure in the embodiments of the present invention is obtained.  
      Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.