Abstract:
An image archiving system is provided comprising at least one modality for creating images, at least on workstation for viewing and analyzing the images, at least one archive for storing the images, a proxy to handle the data communication between the modality, workstation and archive and a network for communicably connecting the components of the system. Images and other data associated with the images to be archived may be sent to a proxy to determine which of the archives the images and other data should be stored and the proxy archives the images and other data in the appropriate archive.

Description:
[0001]     This application claims priority from U.S. provisional application No. 60/628,556 filed Nov. 18, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to systems and methods for image archiving.  
       DESCRIPTION OF THE PRIOR ART  
       [0003]     In medical imaging, picture archiving and communication systems (PACS) are used for the storage, retrieval, distribution and presentation of images. These systems are comprised of computers or networks of computers with storage and communication capabilities. PACS may replace hard-copy methods of managing medical images such as film archives. These systems provide expanded possibilities in the field of medical imaging by providing the capability to perform off-site viewing and reporting, and enabling practitioners in various physical locations to view the same information simultaneously.  
         [0004]     A typical PACS network uses a central server storing a database of images connected to one or more clients via a local area network (LAN) or wide area network (WAN). Clients are typically either workstations where the images are viewed and analyzed or modalities where the images are created. A fill PACS will typically handle images from various modalities such as ultrasonography, radiography, magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT) and X-rays.  
         [0005]     Some of the benefits of using a PACS include the gradual elimination of on-site and off-site film storage which can be expensive, images can be distributed to multiple departments in minutes (e.g. to the emergency room (ER) and the intensive care unit (ICU)), the use of digital measurements and enhancements, and aiding in the elimination of delays associated with images that are unavailable or are misfiled. There are many other benefits associated with PACS. The use of these types of systems has become increasingly more justified as the cost of digital storage continues to decrease.  
         [0006]     The medical images are usually stored in an independent format. The most common format for storing images is DICOM which stands for Digital Imaging and Communications in Medicine. DICOM is a comprehensive set of standards for handling, storing and transmitting information in the field of medical imaging. DICOM includes a file format definition and a network communication protocol. DICOM was established to enable the integration of scanners, servers, workstations and network hardware from multiple vendors to be used in a PACS.  
         [0007]     DICOM Information Object Definitions (IOD) include a header with standardized as well as free-form fields and, if applicable, a body of image data. It should be noted that some DICOM IOD do not contain image data, for instance DICOM Key Image Note. A single DICOM IOD can also contain more than one image, which allows for the storage of image volumes and/or animations. Image data can be compressed using a variety of compression standards such as joint photographic experts group (JPEG), Lempel-Ziv-Welch (LZW) or run-length encoding (RLE).  
         [0008]     The first PACS were deployed over ten years ago, and therefore there are a number of existing PACS sites in the world. Some owners of PACS may be upgrading to newer version software in order to support newer modalities such as PET/CT, DICOM Structured Report, Key Image Notes and Greyscale Presentation State. Some owners may even migrate to a new vendor. Archive migration generally poses a major challenge due to the shear volume (usually on the order of terabytes) of data involved in successfully completing the migration. The co-operation of both the existing and the new vendor may be needed which is often difficult as they usually are competing entities.  
         [0009]     Software upgrades and new versions of PACS can occur periodically and when an institute decides to switch to a new PACS vendor, the institutes would either migrate all of the existing data to a new archive or would run both of the systems in parallel. Both of these outcomes have an impact on workflow and therefore discourages institutes to switch to other vendors even though the technologies provided by such vendors may be superior. Another possible scenario is that the institution may want to add a new system, such as mammography, while keeping an existing PACS.  
         [0010]     It is therefore an object of the present invention to obviate or mitigate the above mentioned disadvantages.  
       SUMMARY OF THE INVENTION  
       [0011]     In one aspect, an image archiving system is provided. The image archiving system comprises at least one device capable of viewing images and handling data associated with the images; a plurality of archives, each of the plurality of archives capable of storing the images and the data associated with the images; a proxy handling data communication between the at least one device and the plurality of archives and determining a location at which each of the images is to be stored, the location comprising one of the plurality of archives; and a network communicably connecting the at least one device, the plurality of archives, and the proxy to enable the transfer of data therebetween.  
         [0012]     In another aspect, a method for archiving a plurality of images is provided. The method uses an archiving system connected through a network and comprises the steps of sending an image to be archived to a proxy; the proxy determining a location at which the image is to be stored, the location comprising one of a plurality of archives; and the proxy storing the image at the location.  
         [0013]     In yet another aspect a method for archiving a set of results using an archiving system connected through a network is provided, the results being associated with a corresponding image. The method comprises the steps of sending the results to a proxy; the proxy determining a location at which the results are to be stored, the location comprising one of a plurality of archives storing the corresponding image; and the proxy storing the results at the location and associating the results with the image.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     An embodiment of the invention will now be described by way of example only with reference to the appended drawings wherein:  
         [0015]      FIG. 1  is a schematic representation of an image archiving system supporting new and legacy archives.  
         [0016]      FIG. 2  is a flow chart showing an image archiving procedure.  
         [0017]      FIG. 3  is a flow chart showing a data query.  
         [0018]      FIG. 4  is a flow chart showing a data retrieval procedure.  
         [0019]      FIG. 5  is a flow chart showing a results archiving procedure. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Referring therefore to  FIG. 1 , an image archiving system is generally denoted by numeral  10 . Images in the archiving system  10  are created by a device typically referred to as a modality  12  and are most often viewed using another device referred to as a workstation  14 . Although  FIG. 1  shows one modality  12  and one workstation  14  it will be appreciated that there may be any number of modalities and workstations. Moreover, it will also be appreciated that one or more modality  12  and one or more workstation  14  may also constitute a single device or unit. The archiving system  10  would preferably be a PACS. The modality  12  is typically an imaging machine supporting one of the standard medical imaging modalities such as CT or MRI etc. The workstation  14  may be any device capable of sending and receiving digital information as well as viewing and manipulating this digital information. Typically, the workstation  14  will be a personal computer (PC) with a visual interface (e.g. a monitor), and one or more input devices such as a keyboard and mouse.  
         [0021]     The archiving system  10  exemplified in  FIG. 1  has a new archive  16  supporting new modalities, software versions etc., and a legacy archive  18  which stores data from previous software versions, vendors, old modalities etc. A proxy  20  provides the central logic of the entire archiving system  10 . The proxy  20  may hide the backend storage systems  16 ,  18  from the external users (e.g. modality  12  and workstation  14 ) so that these external systems  12 ,  14  communicate with a single node. This node will preferably support the DICOM standard and may be capable of interfacing with formats supporting new and old modalities. Communication is facilitated by a network  22 . Although the network  22  is not explicitly shown, it will be appreciated that the arrows identified by numeral  22  in  FIG. 1  are representative of the communicable connections provided by the network  22 .  
         [0022]     The proxy  20 , in part, contains the logic to save and retrieve data to and from the appropriate storage (e.g. new archive  16  or legacy archive  18 ). The proxy  20  is preferably implemented using a single software module that proxies all data requests and routes the data to the corresponding storage system (e.g. new archive  16  or legacy archive  18 ) using the network  22 . The modality  12  and workstation  14  may only need to communicate with a single node of the new software (e.g. through the proxy  20 ) and the logic behind the data retrieval will then generally be hidden from the user. Consequently, the archive system  10  may appear to be a single system but really provides seamless archiving for multiple archive storages, the storages being connected to the network  22  and being governed by the proxy  20 .  
         [0023]     It will be appreciated that although  FIG. 1  depicts a single new archive  16  and a single legacy archive  18 , there may be any number of each. The proxy  20  provides a central communication node for the modality  12  and workstation  14  regardless of the number of new or legacy archives incorporated into the archive system  10 .  
         [0024]     The proxy  20  in general, provides the central logic of the archive system  10  and contains the software that preferably proxies all data requests. Therefore, the proxy  20  is preferably responsible for executing all storage and retrieval procedures. An exemplary image archiving procedure  200  is shown in  FIG. 2 . The modality  12  generates an image in its respective format at step  202 . This image may then be sent to the proxy  20  at step  204 . The proxy  20  may then determine whether the image should be archived in e.g. the new archive  16  or the legacy archive  18  at step  206 .  
         [0025]     The determination of which archive should store a particular image is typically based on predetermined criteria, such as the formats supported by the particular archive, and whether or not new formats are to be added as supplemental data to the image. For example, a legacy archive  18  may support CT and MRI images, and the new archive  16  may additionally support presentation (PR) objects. In such an example, when a CT scanner sends a study to the proxy  20  at step  204 , the proxy  20  would forward the study to the legacy archive  18  at step  206 , since the legacy archive supports such a format. However, when a user later reviews a study (an example is explained later) and saves a PR object, the proxy  20  would forward the object to the new archive  16 , since it supports such a format. Therefore, the original image data is saved to the legacy archive  18  and the new object to the new archive  16 , i.e. certain objects may be saved to different archives even though they are related in some way.  
         [0026]     Typically, the legacy archive  18  is used to maintain old data and would thus be used for reading data only. New objects (e.g. PR object of a review) are forwarded by the proxy  20  to the new archive  16 , since the new archive supports PR objects. This avoids the need for migration of data from the legacy archive  18  to the new archive  16 . The proxy  20  may also incorporate rules that are based on proximity to the workstation  14 . For example, objects may be retrieved from certain archives or stored in certain archives based on how accessible a particular archive is for the user at the workstation  14 . This may be preferable when different archives can perform similar tasks, and the one with the best accessibility would then be chosen. It will be appreciated that other rule sets may be used based on the capabilities of the system  10  and the availability of new and legacy archives.  
         [0027]     If the legacy archive  18  is to continue to act as the storage location for that particular modality, the proxy  20  may forward a storage request  208  to the legacy archive  18 . If, for example, the legacy archive  18  cannot handle the format of the modality  12 , a new DICOM class is being used, or if it is desired to use the new archive  16  for storing all new data, the proxy  20  may then forward the storage request  214  to the new archive  16 .  
         [0028]     As the storage request is being processed in either case (e.g. steps  208  or  214 ), the proxy  20  may be required to wait for a response from the archive whether or not the storage succeeds at steps  210 ,  216  respectively. The proxy  20  may then communicate directly to the modality  12  through the network  22  to report the success or failure of the archiving procedure  200  at step  218 .  
         [0029]     Images that have been archived may be requested by a user at the workstation  14 . The user may first perform a query  300  from the workstation  14  for a typical reading of data stored in the archives  16 ,  18 . A reading may include a review of the current study and prior studies if available and/or applicable. This query  300  is shown in  FIG. 3 . The workstation  14  may then make a request to the proxy  20  to search for a particular patient as well as studies associated with that patient at step  302 . The proxy  20  will typically search both the new archive  16  and the legacy archive  18  for the patient studies. This is shown as a set of parallel steps  304  and  306 . It will be appreciated that steps  304  and  306  may also be done sequentially and need not be done in parallel. The results from searching both archives may be consolidated at step  308  and these results can be passed back to the workstation  14  at step  310 .  
         [0030]     The results provided to the user of the workstation  14  in step  310  would typically be reviewed and the user would then decide which studies they would like transferred to the workstation  14 . This data retrieval procedure  400  is shown in  FIG. 4 . The results  310  from the query  300  can be reviewed at step  402 . During the review  402 , the user will typically decide at this time which studies it wishes to transfer to the workstation  14 .  
         [0031]     The user may request the transfer of the desired study or studies through the proxy  20 . at step  404 . This request will also typically include a request to transfer data to be stored at the destination, that being the workstation  14  in this example. The proxy  20  may then process the request at step  406 . In this step the proxy  20  will generally have information from the query  300  pertaining to the location of the data (e.g. new archive  16  or legacy archive  18 ). The proxy&#39;s request  406  will typically include searching the archives  16 ,  18  to determine whether or not the data is available or even exists. The data, if located, may then be transferred by the proxy  20  back to the destination (e.g. the workstation  14 ) at step  408 .  
         [0032]     When a user reviews a study which has been transferred to them at the workstation  14 , various readings may be done and results from these readings would then be archived with the data of the study. Results from a reading may include a DICOM structured report, DICOM Key Object Notes, or a DICOM Greyscale Presentation State. A procedure  500  for archiving results is shown in  FIG. 5 . The results report(s) are generated by the user at the workstation  14  at step  502 . A request may then be made to archive the results at step  504 . This request is preferably made through the proxy  20 . The proxy  20  may then decide at which location to store the results in step  506 .  
         [0033]     The studies being reviewed by the user may include data which has been archived in the new archive  16 , the legacy archive  18  or both. Results from a reading may need to be archived in the legacy archive  18  but would typically be archived to the new archive  16  especially when a new DICOM format is being used. Other reasons may be dictated by the specific system and/or policies of the institute using the archive system  10 . At step  508 , the proxy  20  may then determine whether the results should be archived in, for example, the new archive  16  or the legacy archive  18 . As discussed above, typically the results would be saved in the new archive  16 , since the legacy archive  18  is preferably only used for reading old data. Based on this determination, the proxy  20  may then forward the results to either the new archive  16  or legacy archive  18  in steps  510  and  512  respectively.  
         [0034]     Therefore, the proxy  20  preferably handles any procedure related to image retrieval and image archiving by providing a single node for the users of the modality  12  and workstation  14  to communicate with. This enables the archive system  10  to run new and legacy archives (e.g. archive  16  and archive  18 ) in parallel, while being substantially transparent to the users of the system  10 . Accordingly, for example, PACS from different vendors using different DICOM class versions can be used by the archive system  10  without the need to migrate legacy images to a new system or to run more than one separate system requiring separate nodes for communication. Consequently, workflow is substantially unaffected by archive system upgrades, new modalities or a change in vendor.  
         [0035]     It will be appreciated that although the present invention has been described in terms of an image archiving system suitable for archiving medical images using PACS and the DICOM standard, it is suitable for and may be used for other image archiving systems.  
         [0036]     Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto.