Abstract:
A recording sheet usage count evaluation method enabling, even when plural radiation imaging apparatuses and plural radiographic image reading apparatuses exist, accurate evaluation of cumulative working frequencies of recording sheets commonly used in those apparatuses. The method includes the steps of (a) receiving recording sheet identification information with image data from a radiographic image reading apparatus; (b) counting a usage count of each recording sheet on a basis of the recording sheet identification information received at step (a), weighting a count value in accordance with a set condition, and accumulating the weighted count value to store the accumulated count value in correspondence with the recording sheet identification information; and (c) calculating a total count value for each recording sheet by referring to count values stored in other medical image processing apparatuses and adding the count values to the count value stored at step (b).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to recording sheet usage count evaluation method and apparatus for evaluating a cumulative usage count of each recording sheet (also called “imaging plate”) in a radiation imaging system, in which a radiographic image is recorded on the recording sheet by imaging an object by using a radiation imaging apparatus, image data is obtained by reading the radiographic image recorded on the recording sheet by using a radiographic image reading apparatus, and the image data is processed by using a medical image processing apparatus. Further, the present invention relates to a medical image processing apparatus using such a recording sheet usage count evaluation method.  
         [0003]     2. Description of a Related Art  
         [0004]     Conventionally, an imaging method using a radiation (X-ray, α-ray, β-ray, γ-ray, electron beam, ultraviolet ray, or the like) is utilized in various fields, and particularly, employed as one of the most important means for diagnosis in a medical field. Since a first X-ray photograph was realized, X-ray photography has been repeatedly improved, and presently, a method using a combination of a fluorescent screen and an X-ray film is going mainstream. On the other hand, in recent years, various digitized apparatuses such as X-ray CT apparatus, ultrasonic apparatus or MRI apparatus are in practical use, and construction of diagnosis information processing systems in hospitals is being developed. As for X-ray images also, many studies have been made for digitization, and a radiation imaging method using a photostimulable phosphor has been established, which attracts many attentions as a method that will replace conventional X-ray photography.  
         [0005]     The photostimulable phosphor (storage phosphor) is a substance in which a portion of radiation energy is stored when the radiation is irradiated thereon, and thereafter, stimulated fluorescence is emitted according to the stored energy when excitation light such as visible light is irradiated thereon. The existence of the photostimulable phosphor has conventionally been known. The radiation imaging method using the photostimulable phosphor will be described below. First, by using a radiation imaging apparatus, a radiographic image of an object such as a human body is taken on a recording sheet (imaging plate), onto which photostimulable phosphor is applied, and recorded thereon. Then, by using a radiographic image reading apparatus, the recording sheet is scanned with excitation light such as a laser beam, and thereby, stimulated fluorescent light is read out photoelectrically to obtain image data. Further, by using a medical image processing apparatus, after the image data is properly processed, the radiographic image is output on a display such as a CRT, or printed out on a film by using a laser printer, etc., and thus, the radiographic image can be displayed as a visual image.  
         [0006]     Such a radiation imaging method has a performance comparable to the conventional X-ray photography in terms of imaging sensitivity and image quality. For example, as compared to the conventional X-ray photography, the exposure range is extremely large, and the response of the stimulated fluorescent light to the light exposure is substantially proportional throughout the whole exposure range. Accordingly, when the object is imaged under any radiation dose, it is possible to capture the luminescent range of the image existent therein, and obtain a digitized signal through normalization without shortage or excess. Also, by combining the obtained signal with a proper image processing method, it is possible to constantly provide an image of excellent quality under a variety of imaging conditions. Further, because of direct acquisition of digitized image information, not only long-term preservation of a large amount of data without deterioration, but also development for use in a medical diagnosis information system becomes possible.  
         [0007]     Now, generally, the recording sheet is contained into a case, called “cassette”, when in use. As an identification mark for distinguishing a recording sheet for imaging one patient from a recording sheet for imaging another patient, a barcode is attached to the recording sheet, which can be viewed through a window provided on the cassette.  
         [0008]     When the recording sheet contained in the cassette is repeatedly used for radiation imaging and radiographic image reading, the characteristic thereof is degraded because of bending in the radiographic image reading apparatus or secular change, which tends to bring about deterioration of the image quality. In order to estimate such image quality deterioration beforehand, it is desired to confirm a cumulative usage count of each recording sheet.  
         [0009]     However, in general, the recording sheet is neither specified for each radiation imaging apparatus nor specified for each radiographic image reading apparatus, but commonly used for a plurality of radiation imaging apparatuses or a plurality of radiographic image reading apparatuses. Therefore, it has not been realized to confirm the cumulative usage count of each recording sheet. Further, the degree of degradation in the characteristic of the recording sheet varies with difference in type of the radiographic image reading apparatuses, difference in installation environment of the radiographic image reading apparatuses and difference in manufactured time of the recording sheets, and therefore, it is desired to confirm the usage state of the recording sheet, taking into account at least one of the above factors.  
         [0010]     As a related art, Japanese Patent Application Publication JP-P2001-154297A discloses, in an image information record reading apparatus of a built-in type, to efficiently perform confirmation of the necessity for cleaning and exchange of sheets. In the image information record reading apparatus, there are provided counter means for counting the frequency of feeding a sheet (IP: imaging plate), a display panel for indicating a counted count value, and a buzzer for generating a warning beep depending on a predetermined frequency when the count value reaches the predetermined frequency. By using the count value indicated on the display panel or the warning beep generated by the buzzer, a user can decide the necessity of cleaning or exchange of the sheet (IP).  
         [0011]     However, the art disclosed in the above JP-P2001-154297A is limited to an image information record reading apparatus of a build-in type, and it is not possible to apply to a general system in which a recording sheet is commonly used to a plurality of radiation imaging apparatuses or a plurality of radiographic image reading apparatuses.  
         [0012]     Further, Japanese Patent Application Publication JP-P2003-220054A discloses, in a medical image reading system, to achieve a reduced maintenance work as well as a reduced cost, to enable prompt handling at the time of the occurrence of an error, and to maintain each apparatus constituting the medical image reading system to an optimal state. In the device information collection processing of the above system, a control section in a controller stores error information in regard to the controller, a reservation device and a reading device into an error log information table for each apparatus, adds up an error occurrence frequency for each error item, and makes an error log information indication screen to be displayed on a display section.  
         [0013]     However, the medical image reading system as shown in FIG. 1 of JP-P2003-220054A includes only one reading apparatus (radiographic image reading apparatus), and no suggestion is made in regard to application to a general system in which a photostimulable phosphor plate (recording sheet) is commonly used for a plurality of radiation imaging apparatuses or a plurality of radiographic image reading apparatuses.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention has been achieved in consideration of the above-mentioned problems. It is a first object of the present invention to provide recording sheet usage count evaluation method and apparatus capable of evaluating, even in the case where a plurality of radiation imaging apparatuses and a plurality of radiographic image reading apparatuses exist, a cumulative usage count of a recording sheet for common use in those apparatuses, and capable of reflecting difference in type of the radiographic image reading apparatuses, etc. Further, it is a second object of the present invention to provide a medical information processing apparatus employing such a recording sheet usage count evaluation method.  
         [0015]     In order to achieve the aforementioned objects, a recording sheet usage count evaluation method according to one aspect of the present invention is a method of evaluating a usage count of each recording sheet in a radiation imaging system including at least one radiation imaging apparatus for imaging an object by irradiating the object with radiation to record a radiographic image on the recording sheet, at least one radiographic image reading apparatus for reading the radiographic image recorded on the recording sheet to obtain image data, and a plurality of medical image processing apparatuses capable of processing the image data received from the at least one radiographic image reading apparatus, and the method comprises the steps of: (a) receiving, in one medical image processing apparatus, recording sheet identification information for use in identifying the recording sheet, together with the image data obtained by reading the radiographic image recorded on the recording sheet, from the at least one radiographic image reading apparatus; (b) counting, in the one medical image processing apparatus, a usage count number of each recording sheet on a basis of the recording sheet identification information received at step (a), weighting a count value in accordance with a set condition, and accumulating the weighted count value to store the accumulated count value in correspondence with the recording sheet identification information; and (c) calculating, in the one medical image processing apparatus, a total count value for each recording sheet by referring to count values stored in other medical image processing apparatuses and adding the count values in the other medical image processing apparatuses to the count value stored at step (b), in accordance with an operation by an operator and/or a set condition.  
         [0016]     Further, a medical image processing apparatus according to one aspect of the present invention is an apparatus for processing image data and evaluating a usage count of each recording sheet and to be used with at least one radiation imaging apparatus for imaging an object by irradiating the object with radiation to record a radiographic image on the recording sheet and at least one radiographic image reading apparatus for reading the radiographic image recorded on the recording sheet to obtain the image data, and the apparatus comprises: reception control means for controlling receiving operation to receive recording sheet identification information for use in identifying the recording sheet, together with the image data obtained by reading the radiographic image recorded on the recording sheet, from the at least one radiographic image reading apparatus; image processing means for processing the image data received under control of the reception control means; counting means for counting a usage count number of each recording sheet on a basis of the recording sheet identification information received under control of the reception control means, weighting a count value in accordance with a set condition, and accumulating the weighted count value to store the accumulated count value into a storage section in correspondence with the recording sheet identification information; and calculating means for calculating a total count value for each recording sheet by referring to count values stored in other medical image processing apparatuses and adding the count values in the other medical image processing apparatuses to the count value stored in the storage section, in accordance with an operation by an operator and/or a set condition.  
         [0017]     Still further, a recording sheet usage count evaluation apparatus according to one aspect of the present invention is an apparatus for evaluating a usage count of each recording sheet and to be used with at least one radiation imaging apparatus for imaging an object by irradiating the object with radiation to record a radiographic image on the recording sheet, at least one radiographic image reading apparatus for reading the radiographic image recorded on the recording sheet to obtain image data, and a plurality of medical image processing apparatuses capable of processing the image data received from the at least one radiographic image reading apparatus, and the apparatus comprises: reception control means for controlling receiving operation to receive recording sheet identification information for use in identifying the recording sheet, when the recording sheet identification information is transmitted together with the image data obtained by reading the radiographic image recorded on the recording sheet, from the at least one radiographic image reading apparatus to any one of the plurality of medical image processing apparatuses; and counting means for counting a usage count number of each recording sheet on a basis of the recording sheet identification information received under control of the reception control means, weighting a count value in accordance with a set condition, and accumulating the weighted count value to store the accumulated count value into a storage section in correspondence with the recording sheet identification information.  
         [0018]     According to the present invention, by counting the usage count number of each recording sheet, weighting the count value in accordance with a set condition, and accumulating the weighted count value to store the accumulated count value in correspondence with the recording sheet identification information, even in the case where a plurality of radiation imaging apparatuses and a plurality of radiographic image reading apparatuses exist, it becomes possible to evaluate a cumulative usage count of a recording sheet which is commonly used in those apparatuses, and at the time of the evaluation, to reflect difference in type of the radiographic image reading apparatuses, etc. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is a block diagram illustrating a configuration of a radiation imaging system employing a recording sheet usage count evaluation method according to a first embodiment of the present invention;  
         [0020]      FIG. 2  is a block diagram illustrating the configuration of the radiation imaging apparatus as shown in  FIG. 1 ;  
         [0021]      FIG. 3  is a block diagram illustrating the configuration of the radiographic image reading apparatus as shown in  FIG. 1 ;  
         [0022]      FIG. 4  is a block diagram illustrating the configuration of a medical image processing apparatus according to the first embodiment of the present invention;  
         [0023]      FIG. 5  is a flowchart illustrating a recording sheet usage count evaluation method according to the first embodiment of the present invention;  
         [0024]      FIG. 6  is a diagram illustrating an example of a transfer path in a first radiographic image reading apparatus;  
         [0025]      FIG. 7  is a diagram illustrating an example of a transfer path in a second radiographic image reading apparatus;  
         [0026]      FIG. 8  is a block diagram illustrating a configuration of a medical image processing apparatus according to a second embodiment of the present invention; and  
         [0027]      FIG. 9  is a block diagram illustrating a configuration of a recording sheet usage count evaluation server according to one embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     Hereinafter, preferred embodiments of the present invention will be described referring to drawings, wherein the same reference numerals are given to the same structural elements, and the description thereof will be omitted.  
         [0029]      FIG. 1  is a block diagram illustrating the configuration of a radiation imaging system employing a recording sheet usage count evaluation method according to a first embodiment of the present invention. As shown in  FIG. 1 , the radiation imaging system includes at least one radiation imaging apparatus ( FIG. 1  shows a plurality of radiation imaging apparatuses  10   a ,  10   b , etc.) for imaging an object to be inspected by irradiating the object with radiation to record a radiographic image on a photostimulable phosphor sheet (which is also referred to as “recording sheet” or “imaging plate”), at least one radiographic image reading apparatus ( FIG. 1  shows a plurality of radiographic image reading apparatuses  20   a ,  20   b , etc.) for photoelectrically reading information such as radiographic image recorded on the recording sheet to generate image data and image attendant information, and a plurality of medical image processing apparatuses  30   a ,  30   b , etc. for receiving the image data from any one of the radiographic image reading apparatuses, performing a variety of processing of the image data, and displaying or outputting the image.  
         [0030]     Each of the medical image processing apparatuses  30   a ,  30   b , etc. processes the image data, and also counts a usage count number of each recording sheet to generate a count value, weights the count value according to a set condition, accumulates the weighted count value, and compares the accumulated count value with a recommended usage count of the recording sheet. Further, the medical image processing apparatuses  30   a ,  30   b , etc. are also used as consoles for controlling the respective radiation imaging apparatuses  10   a ,  10   b , etc., and imaging condition is transmitted and received between each medical image processing apparatus and respective radiation imaging apparatus. Here, the radiographic image reading apparatuses  20   a ,  20   b , etc. and the medical image processing apparatuses  30   a ,  30   b , etc. are connected to each other via a network N 1 . Further, when necessary, external apparatuses such as a recording sheet usage count evaluation server  50  and an image server  60  are connected to the network N 1 .  
         [0031]      FIG. 2  is a block diagram illustrating the configuration of the radiation imaging apparatus as shown in  FIG. 1 . The radiation imaging apparatus  10  includes an imaging position elevation mechanism  11  for vertically moving the position of a recording sheet  1  to adjust the imaging position of the object, an imaging stand  12  for positioning the feet of the object, a radiation generating section  13  for irradiating the object with radiation, a barcode reader  14  for reading a barcode attached to the recording sheet  1  as an identification mark, an input section  15  for use in inputting a variety of instructions and imaging conditions, and an imaging control section  16  for controlling the radiation generating section  13 , etc. according to the given imaging conditions.  
         [0032]     The barcode reader  14  is desirably mounted on the imaging stand  12  so that the barcode on the recording sheet  1  can be read automatically through a window provided on a cassette, when the cassette that contains the recording sheet  1  is set onto the imaging stand  12 . However, instead of such fixed mounting, it is possible that the barcode reader  14  is not fixed and the barcode is read manually. Further, the imaging control section  16  is connected to the medical image processing apparatuses, and controls each section based on the signals received from the medical image processing apparatuses.  
         [0033]     The recording sheet  1  for use in the radiation imaging is a sheet having a photostimulable phosphor substance coated thereon, on which the information of the object is recorded when irradiated with radiation through the object. The radiation imaging of the object is performed under predetermined imaging conditions, and the resultant radiographic image is recorded on the recording sheet  1 . After imaging, the recording sheet  1  is set on any one of the radiographic image reading apparatuses.  
         [0034]      FIG. 3  is a block diagram illustrating the configuration of the radiographic image reading apparatus as shown in  FIG. 1 . In the radiographic image reading apparatus  20  as shown in  FIG. 3 , a light beam output from a laser light source  21  scans the surface of the recording sheet  1  through an optical scanning section  22 . By the scanning, the recording sheet  1  is irradiated with the light beam, and from an area irradiated with the light beam, there is produced stimulated fluorescent light, quantity of which depends on the recorded and stored radiographic image information. The stimulated fluorescent light is photoelectrically detected by a photomultiplier (photoelectron multiplier)  23 , so that an analog signal is output therefrom, amplified in an amplifier  24 , and then digitized in an A/D converter  25 . Also, the barcode attached to the recording sheet  1  is read by a barcode reader  26 , and the barcode information is used as image attendant information corresponding to patient information and examination information. The image data and the barcode information thus generated are transmitted from an output section  27  to the medical image processing apparatus via the network N 1 .  
         [0035]      FIG. 4  is a block diagram illustrating the configuration of the medical image processing apparatus according to the first embodiment of the present invention. The medical image processing apparatus  30  includes an input section  31  such as a keyboard or a mouse, for inputting a variety of instructions, etc., a display section  32  such as a CRT display, for displaying an image, a printer  33  for printing an image on a film, etc., an interface  34  to which the input section  31  to the printer  33  are connected, a memory  35  for temporarily storing the image data and the image attendant information received from the radiographic image reading apparatus, a hard disk  36 , a hard disk controller  37 , a network interface  38 , and a central processing unit (hereinafter referred to as CPU)  40 . The units from the memory  35  to the CPU  40  are connected to each other via a bus line BL.  
         [0036]     In the hard disk  36 , software (control program) for actuating the CPU  40  is stored. Here, as a recording medium for storing the control program, external hard disk, flexible disk, MO, MT, RAM, CD-ROM, DVD-ROM or the like may be used as well as the built-in hard disk  36 . As functional blocks, a reception control section  41 , an image processing section  42 , a count section  43 , a total calculation section  44 , a usage state notification section  45  and an output section  46  are configured by means of the CPU  40  and the software (control program).  
         [0037]     The reception control section  41  controls reception operation so as to receive, from any one of the radiographic image reading apparatuses, the image data obtained by reading the radiographic image recorded on the recording sheet and recording sheet identification information for use in identifying the recording sheet. In the present embodiment, as the recording sheet identification information, the barcode information generated in the radiographic image reading apparatus is used. Further, the image processing section  42  performs image processing such as gradation processing or space frequency processing onto the image data received under the control of the reception control section  41 .  
         [0038]     The count section  43  counts a usage count number of each recording sheet on the basis of the recording sheet identification information received under the control of the reception control section  41 , weights a count value according to a set condition, accumulates the weighted count value, and stores the accumulated count value into a storage section such as the memory  35 , the hard disk  36  or the like on correspondence with the recording sheet identification information.  
         [0039]     The recording sheet has a laminate structure including a reflective layer, a phosphor layer and a protection layer formed on a base layer of a polyethylene terephthalate material having a thickness of 0.2 mm or on that order, among which the phosphor layer occupies a principal portion in the thickness. Accordingly, the recording sheet has a characteristic being gradually degraded by scratches and folds caused by running or being bent through the transfer path of the radiographic image reading apparatus. Here, the degree of degradation in the recording sheet characteristic varies depending on the factors including difference in type of the radiographic image reading apparatuses, difference in installation environment of the radiographic image reading apparatuses and difference in manufacturing time of the recording sheets. Therefore, the weighting condition is set based on at least one of the above factors.  
         [0040]     For example, since the length of the transfer path, the number of bends, the bending direction or the bending angle of the recording sheet is different depending on the type of the radiographic image reading apparatus, the weighting condition may be set corresponding to such matters, or the weighting condition may be set simply corresponding to the type of the apparatus. Also, since the temperature or the humidity inside the radiographic image reading apparatus differs depending on the installation environment of the radiographic image reading apparatus, the weighting condition may be set corresponding to such matters. Further, since the manufacturing time or the manufacturing line differs in the recording sheet to be used, the weighting condition may be set corresponding to such matters. Alternatively, the weighting condition may be set in correspondence with combination of two or more of the above matters.  
         [0041]     The total calculation section  44  refers to the count values stored in other medical image processing apparatuses and adding the count values in other medical image processing apparatuses to the count value stored in the storage section to calculate the total count value for each recording sheet, according to an operation by an operator or a set condition.  
         [0042]     The usage state notification section  45  compares the total count value calculated by the total calculation section  44  with a set recommended usage count of the recording sheet, and thus obtains a comparison result. The recommended usage count of the recording sheet is set based on, for example, a recommended usage count (useful count number) described in the product specification, or the like, of the recording sheet provided by the recording sheet manufacturing company. Further, based on the obtained comparison result, the usage state notification section  45  generates a signal for notifying of the usage state of each recording sheet by image or voice, and outputs the above signal to the output section  46 .  
         [0043]     The output section  46  outputs the image data, on which image processing is performed by the image processing section  42 , onto the display section  32  or the printer  33  via the interface  34 . Thereby, the radiographic image is displayed on the screen of the display section  32 , or printed on a film, etc. Also, based on the signal input from the usage state notification section  45 , the output section  46  outputs an image signal or a voice signal to the display section  32  via the interface  34  the output section  46  to make the display section  32  indicate the usage state of each recording sheet by image or voice. Accordingly, the usage state of each recording sheet is notified by image or voice at the display section  32 .  
         [0044]     In the present embodiment, although the units from the reception control section  41  to the output section  46  are configured by means of the CPU and the software, it may be possible to configure them by using a digital circuit and an analog circuit.  
         [0045]     Next, the recording sheet usage count evaluation method according to the first embodiment of the present invention will be described, referring to  FIGS. 1-7 .  FIG. 5  is a flowchart illustrating the recording sheet usage count evaluation method according to the first embodiment of the present invention.  
         [0046]     As shown in  FIG. 5 , at first, the registration of an imaging object is performed in the medical image processing apparatus  30 . Namely, at step S 31 , patient information and examination information such as an imaging menu and an imaging condition are registered. In ordinary imaging, a plurality of times of imaging is performed at a time, and therefore, patient information and examination information for a plurality of times of imaging are collectively registered.  
         [0047]     At the time of radiation imaging, at step S 11 , when the operator sets a cassette containing a recording sheet  1  on the imaging stand  12  of the radiation imaging apparatus  10 , the barcode reader  14  reads the barcode being attached to the recording sheet  1  as identification mark. At step S 12 , the radiation imaging apparatus  10  transmits to the medical image processing apparatus  30  an imaging information request signal including the barcode information that is obtained by reading the barcode of the recording sheet  1 , so as to request the patient information and the examination information in regard to the imaging in which the above recording sheet  1  is used. In the present embodiment, although the barcode reader  14  is connected to the imaging control section  16  of the radiation imaging apparatus  10 , the barcode reader  14  may be directly connected to the medical image processing apparatus  30  through a wired or a wireless link.  
         [0048]     At step S 32 , the medical image processing apparatus  30  registers the barcode information included in the received imaging information request signal, in association with the patient information and the examination information in regard to the imaging at this time, and then, transmits an imaging information response signal including the patient information and the examination information concerned to the radiation imaging apparatus  10  at step S 33 .  
         [0049]     At step S 13 , the radiation imaging apparatus  10  sets the imaging condition based on the examination information included in the received imaging information response signal. Further, at step S 14 , radiation imaging is performed under the set imaging condition. Thereafter, at step S 15 , the operator removes the cassette set on the imaging stand  12  of the radiation imaging apparatus  10 , and transfers the cassette to the radiographic image reading apparatus  20 .  
         [0050]     In the radiation imaging, generally, it is not fixed which recording sheet is used in which radiation imaging apparatus. Also, as shown in  FIG. 1 , the cassette containing the recording sheet of No. 0001 on which imaging has been completed by the radiation imaging apparatus  10   a  may be set to the radiographic image reading apparatus  20   a  or the radiographic image reading apparatus  20   b . Similarly, the cassette containing the recording sheet of No. 0002 on which imaging has been completed by the radiation imaging apparatus  10   b  may be set to the radiographic image reading apparatus  20   b  or the radiographic image reading apparatus  20   a.    
         [0051]     Again, referring to  FIG. 5 , at step S 21 , the radiographic image reading apparatus  20  reads the barcode attached to the recording sheet, and at step S 22 , generates image data by reading the radiographic image recorded on the recording sheet. Thereafter, at step S 23 , the radiographic image reading apparatus  20  transmits the barcode information together with the image data, to the medical image processing apparatus  30 .  
         [0052]     The reception control section  41  in the medical image processing apparatus  30  controls receiving operation so as to receive the barcode information together with the image data from the radiographic image reading apparatus  20 . The barcode information is used as recording sheet identification information for identifying the recording sheet. Since the barcode information is associated with the patient information and the examination information in advance, it is possible to associate the image data, that is received together with the barcode information, with the patient information and the examination information. Alternatively, as means for identifying the recording sheet, it is possible to use an RFID tag or a size of the recording sheet other than the barcode. For example, when there is only one recording sheet of special size, the recording sheet can be identified by the size of the recording sheet.  
         [0053]     At step S 34 , the count section  43  in the medical image processing apparatus  30  counts a usage count number of each recording sheet on the basis of the recording sheet identification information received under the control of the reception control section  41  to generate a count value, weights the count value according to a set condition, accumulates the weighted count value, and stores the accumulated count value into a storage section such as the memory  35  and the hard disk  36 , in correspondence with the recording sheet identification information. Here, the count section  43  may count a usage count number of each recording sheet for each radiographic image reading apparatus, weights the count value according to a set condition, accumulates the weighted count value, and stores the accumulated count value into the storage section in correspondence with the recording sheet identification information.  
         [0054]      FIG. 6  is a diagram illustrating an example of a transfer path in a first radiographic image reading apparatus. In the first radiographic image reading apparatus  20   a , the length of the transfer path is approximately 1 meter, and the recording sheet inserted from an input section IN is transferred to an output section OUT via a bent portion A and a bent portion B. At the bent portion A and the bent portion B, the recording sheet is bent in the same direction.  
         [0055]      FIG. 7  is a diagram illustrating an example of a transfer path in a second radiographic image reading apparatus. In the second radiographic image reading apparatus  20   b , the length of the transfer path is approximately 1 meter, and the recording sheet inserted from an input section IN is transferred to an output section OUT via a bent portion C and a bent portion D. At the bent portion C and the bent portion D, the recording sheet is bent in the opposite directions.  
         [0056]     In the present embodiment, using as a criterion the transfer path of the radiographic image reading apparatus  20   a  as shown in  FIG. 6 , weighting factors are respectively set in proportion to the length of the transfer path, the number of bends and the bending angle. Further, in the case of the opposite bending directions, the degree of degradation in the recording sheet characteristic is large as compared with the case of the same bending direction, and therefore, the weighting factors in regard to the number of bends are set 1.5 times as large. In the following, for the sake of simple explanation, the weighting factor of the radiographic image reading apparatus  20   a  is set at “1”, while the weighting factor of the radiographic image reading apparatus  20   b  is set at “1.5”.  
         [0057]     For example, when the medical image processing apparatus  30   a  as shown in  FIG. 1  receives image data obtained from a recording sheet of No. 0001 from the radiographic image reading apparatus  20   a  for the first time, the medical image processing apparatus  30   a  sets a count value C 1 ( 30   a ) at “1” in regard to the recording sheet of No. 0001. Thereafter, when the medical image processing apparatus  30   a  receives image data obtained from the recording sheet of No. 0001 from the radiographic image reading apparatus  20   a , the medical image processing apparatus  30   a  sets the count value C 1 ( 30   a ) at “2” in regard to the recording sheet of No. 0001. On the other hand, when the medical image processing apparatus  30   a  receives image data obtained from the recording sheet of No. 0001 from the radiographic image reading apparatus  20   b , the medical image processing apparatus  30   a  sets the count value C 1 ( 30   a ) at “2.5” in regard to the recording sheet of No. 0001. Alternatively, medical image processing apparatus  30   a  may count a usage count number of each recording sheet in regard to the radiographic image reading apparatuses  20   a ,  20   b , etc. to obtain count values C 1 ( 20   a ,  30   a ), C 1 ( 20   b ,  30   a ), etc.  
         [0058]     At step S 35 , the total calculation section  44  in the medical image processing apparatus  30  refers to count values stored in other medical image processing apparatuses and adding the count values in other medical image processing apparatuses to the count value stored in the storage section in accordance with an operation by an operator or a set condition, so as to calculate a total count value for each recording sheet.  
         [0059]     For example, the medical image processing apparatus  30   a  as shown in  FIG. 1  accesses the other medical image processing apparatuses  30   b , etc. through the network N 1 , and requests the count values of the recording sheet working frequencies. In response to the above request, the other medical image processing apparatuses  30   b , etc. being requested to send the count values of the recording sheet working frequencies transmit the count values to the medical image processing apparatus  30   a . Thereby, the medical image processing apparatus  30   a  can obtain the count values retained in the other medical image processing apparatuses.  
         [0060]     Here, information related to the other medical image processing apparatuses, which information includes information on the type name and the address thereof, is registered beforehand by employing the hard disk etc. in each medical image processing apparatus. The above registration may be performed automatically via the network N 1 , or manually by the operator, or by using a portable recording medium such as a floppy (registered trademark) disk. In the case where the other medical image processing apparatuses  30   b , etc. are not activated, the total calculation section  44  in the medical image processing apparatus  30   a  indicates a communication error onto the display section  32 , or accesses the other medical image processing apparatuses again after a lapse of time.  
         [0061]     The total calculation section  44  in the medical image processing apparatus  30   a  adds, for example, the count values C 1 ( 30   b ), etc. for the recording sheet of No. 0001 in regard to the medical image processing apparatuses  30   b , etc. to the count value C 1 ( 30   a ) for the recording sheet of No. 0001 in regard to the medical image processing apparatus  30   a , and thereby calculates a total count value S 1 =C 1 ( 30   a )+C 1 ( 30   b )+ . . . for the recording sheet of No. 0001.  
         [0062]     Alternatively, the medical image processing apparatus  30   a  may calculate the total count values for each recording sheet in regard to the respective radiographic image reading apparatuses  20   a ,  20   b , etc.: S N ( 20   a )=C N ( 20   a ,  30   a )+C N ( 20   a ,  30   b )+ . . . , S N ( 20   b )=C N ( 20   b ,  30   a )+C N ( 20   b ,  30   b )+ . . . , and so on. Further, the medical image processing apparatus  30   a  calculates the total count value for the entire radiographic image reading apparatuses: S N =S N ( 20   a )+S N ( 20   b )+ . . . .  
         [0063]     Additionally, resets of the total count values in the above medical image processing apparatuses  30   a ,  30   b , etc. are performed simultaneously. Further, it is possible by a system setting to modify whether or not the total count value is resettable, and in the initial setting, “not resettable” is specified.  
         [0064]     At step S 36 , the usage state notification section  45  in the medical image processing apparatus  30  compares the total count value S N  calculated by the total calculation section  44  with the set recommended usage count of the recording sheet, and thus obtains a comparison result.  
         [0065]     At step S 37 , based on the obtained comparison result, the usage state notification section  45  generates a signal for notifying of a usage state of each recording sheet by image or voice, and outputs the signal to the output section  46 . Based on the signal from the usage state notification section  45 , the output section  46  outputs an image signal or a voice signal onto the display section  32  via the interface  34 , and thereby makes the display section  32  indicate the usage state of each recording sheet by image or voice. Thereby, the usage state of each recording sheet is notified at the display section  32  by image or voice.  
         [0066]     Here, the notification of the recording sheet usage state may be performed when the count value of the recording sheet exceeds the recommended usage count of the recording sheet, or for example, when the count value of the recording sheet becomes 90% of the recommended usage count of the recording sheet. Further, the display of the recording sheet usage state may be performed in an ordinary image processing, without displaying a screen of dedicated use.  
         [0067]     According to the present embodiment, in the medical image processing apparatus, the usage count of each recording sheet can be evaluated with weighting, and thus, it is possible to maintain the radiographic image quality by discarding worn-out recording sheets based on the evaluation result. Further, it is possible to grasp a proper time to exchange the recording sheet.  
         [0068]     Next, the medical image processing apparatus according to a second embodiment of the present invention will be described.  
         [0069]      FIG. 8  is a block diagram illustrating the configuration of a medical image processing apparatus according to the second embodiment of the present invention. In the medical image processing apparatus of the present embodiment, the reception control section  41  in the medical image processing apparatus of the first embodiment as shown in  FIG. 4  is replaced with a reception control section  47 , and the function of the total calculation section  44  is removed.  
         [0070]     As shown in  FIG. 8 , in the medical image processing apparatus  30 , there are configured a reception control section  47 , an image processing section  42 , a count section  43 , a usage state notification section  45  and an output section  46  by means of the CPU  40  and software (control program). When image data and recording sheet identification information are transmitted from any one of the radiographic image reading apparatuses to any one of the medical image processing apparatuses, the reception control section  47  controls receiving operation to receive the recording sheet identification information.  
         [0071]     On receipt of the image data transmitted to the medical image processing apparatus  30 , the image processing section  42  processes the image data. The count section  43  counts a usage count number of each recording sheet on the basis of the recording sheet identification information received under the control of the reception control section  47 , weights a count values according to a set condition, accumulates the weighted count value, and stores the accumulated count value into a storage section such as the memory  35 , the hard disk  36  or the like, in correspondence with the recording sheet identification information.  
         [0072]     The usage state notification section  45  compares the count value stored in the storage section by the count section  43  with a set recommended usage count of the recording sheet, and thus obtains a comparison result. Further, based on the obtained comparison result, the usage state notification section  45  generates a signal for notifying of the usage state of each recording sheet by image or voice, and outputs the signal to the output section  46 .  
         [0073]     the output section  46  outputs an image signal or a voice signal to the display section  32  via the interface  34  based on the signal from the usage state notification section  45 , so as to make the display section  32  indicate the usage state of each recording sheet by image or voice. Thereby, the usage state of each recording sheet is notified by image or voice at the display section  32 .  
         [0074]     Also in the present embodiment, it is possible that the count section  43  counts a usage count number of each recording sheet for each radiographic image reading apparatus, weights the count values according to a set condition, accumulates the weighted count value, and stores the accumulated count value into the storage section in correspondence with the recording sheet identification information, such that the usage state of each recording sheet may be evaluated for each radiographic image reading apparatus.  
         [0075]     According to the present embodiment, when image data and recording sheet identification information are transmitted from any one of the radiographic image reading apparatuses to any one of the medical image processing apparatuses, each medical image processing apparatus receives the recording sheet identification information and counts up a usage count number while weighting the count value to accumulate the weighted count value, and thereby, the usage state of each recording sheet can be evaluated or notified.  
         [0076]     Next, a recording sheet usage count evaluation apparatus according to one embodiment of the present invention will be described. In the present embodiment, instead of evaluating the recording sheet usage count by means of the medical image processing apparatuses  30   a ,  30   b , etc. as shown in  FIG. 1 , a recording sheet usage count evaluation server  50  is separately provided as a recording sheet usage count evaluation apparatus.  
         [0077]      FIG. 9  is a block diagram illustrating the configuration of a recording sheet usage count evaluation server according to one embodiment of the present invention. The recording sheet usage count evaluation server  50  is an apparatus in which the function of the image processing section  42  is removed from the medical image processing apparatus  30  as shown in  FIG. 8 . Further, the recording sheet usage count evaluation server  50  may further have a function as an image server such that image data, patient information and so on are stored into the hard disk  36 .  
         [0078]     As shown in  FIG. 9 , in the recording sheet usage count evaluation server  50 , there are configured a reception control section  47 , a count section  43 , a usage state notification section  45  and an output section  46  by means of the CPU  40  and the software (control program). When image data and recording sheet identification information are transmitted from any one of the radiographic image reading apparatuses to any one of the medical image processing apparatuses, the reception control section  47  controls receiving operation to receive the recording sheet identification information.  
         [0079]     The count section  43  counts a usage count number of each recording sheet on the basis of the recording sheet identification information received under the control of the reception control section  47  to generate a count value, weights the count value according to a set condition, accumulates the weighted count value, and stores the accumulated count value into a storage section such as the memory  35 , the hard disk  36  or the like, in correspondence with the recording sheet identification information.  
         [0080]     The usage state notification section  45  compares the count value stored in the storage section by the count section  43  with the set recommended usage count of the recording sheet, and thus obtains a comparison result. Further, based on the obtained comparison result, the usage state notification section  45  generates a signal for notifying of the usage state of each recording sheet by image or voice, and outputs the above signal to the output section  46 .  
         [0081]     The output section  46  outputs an image signal or a voice signal to the display section  32  via the interface  34  based on the signal input from the usage state notification section  45 , so as to make the display section  32  indicate the usage state of each recording sheet by image or voice. Thereby, the usage state of each recording sheet is notified by image or voice at the display section  32 .  
         [0082]     Also in the present embodiment, the count section  43  counts a usage count number on a basis of each recording sheet for each radiographic image reading apparatus, weights the count value according to a set condition, accumulates the weighted count value, and stores the accumulated count value into the storage section in correspondence with the recording sheet identification information, and thereby, the usage state of each recording sheet may be evaluated for each radiographic image reading apparatus.  
         [0083]     According to the present embodiment, when the image data and the recording sheet identification information are transmitted from any one of the radiographic image reading apparatuses to any one of the medical image processing apparatuses, the recording sheet usage count evaluation server receives the recording sheet identification information and counting a usage count number while weighting the count value, and therefore, is possible to evaluate or notify of the usage state of each recording sheet.