The Research Of On-demand Film Printing Technology And Its Implementation

Film has always been the main carrier of images in the traditional radiology department. However, in the recent years, with the introduction of RIS and PACS, film is now gradually losing the usage in radiology diagnosis. But in China, there is a big fluidity of the patients, they often require the hospitals to provide the films which can be used in campus-wide clinics, thus films will continue to exist in a long time. Because that not all patients need the films, the traditional way of film printing which films are print for every patient just after the examination is finished not only leads to a waste of films but also adds additional work to the nurses such as film sorting and distributing. The on-demand film printing has become an urgent need of hospitals.In the traditional workflow, Radiographers will print the films after doing the necessary pre-processing and setting the print layout on the equipment workstation when the examination is finished. Because the radiographers do not know if the current patient needs the films at this time, how to realize on-demand film printing without changing the original workflow is the main problem this thesis is facing. So in this thesis, we have realized such a system based on the virtual printer technology, in this way, radiographers will do the film printing in the original workflow, but the data of the printing films will be sent to the virtual printer instead of the film printer, the virtual printer receives the data and archives them as electronic films. As the electronic films have contained the pre-processing information and the print layout information themselves, once a patient wants his films, he can get them from the nurses or by self-service, with the electronic films sent to the film printer by the print service, the real films are printed out.In this thesis, we have done research on the two key technologies of on-demand film printing first.■The two-way communication of DICOM printing. The virtual printer needs both to receive the data of the electronic films from the equipment workstation and to send the data to the film printer. Thus, it needs to realize the two-way communication of DICOM printing at the same time as the SCP and SCU. DICOM printing is the most complex DICOM service, and there is a diversity of the realization of DICOM printing by different equipment workstations, which also adds the difficulty to realize DICOM printing SCP. On the basis of detailed analysis of the DICOM printing services, we have realized the two-way communication of DICOM printing in a layered way which can make corresponding to different realization of DICOM printing of equipment workstations.■The recognition of the patient information in the electronic film. When the electronic films were received by the virtual printer, they must be identified by the study ID and the patient ID to realize on-demand printing. Because there are no such DOCOM attributes in the electronic film, the virtual printer must get these information through OCR technology. We have contributed a method to recognize the patient ID and study ID based on the Open source OCR engine "Tesseract", in this method, we can also judge the correctness of the recognition results based on the Study-Patient matching.On the basis of the above research of the key technologies, we have developed such an on-demand film printing system with all the functions of film virtual printer as well as on-demand film printing service. This system has been implemented in hospitals such as the Second Affiliated Hospital of Wenzhou Medical College, the correct matching rate has reached96.5%, the savings rate of films has reached14.8%, so it has proved that there is a good usability of our system, and it can effectively reduce the waste of films.