ABSTRACT
The Medical Diagnostic Imaging Support (MDIS) system at Madigan Army Medical Center (MAMC) has been operational in a phased approach since March 1992. Since then, nearly all image acquisition has been digital with progressively increasing primary softcopy diagnosis used. More than 375,000 computed radiography (CR) images as well as other modality images have been archived. Considerable experience in installation and implementation phasing has been gained. The location and ergonomic aspects of equipment placement were refined with time. The original clinical scenario was insufficiently detailed and additions were made to facilitate smoother and more complete transition toward a filmless environment. The MDIS system effectiveness and performance have been good in terms of operational workload throughout, background operations, and reliability. The important areas regarding reliability are image acquisition, output, display, database operations, storage, and the local area network. Fail-safe strategies have been continually improved to maintain continuous clinical image availability during the times when the MDIS system or components malfunction. Many invaluable lessons have been learned for effective quality assurance in a hospital-wide picture archiving and communication system. These issues include training, operational quality control, practical aspects of CR image quality, and increased timeliness in the generation and distribution of radiographic reports. Clinical acceptability has been a continuous process as each phase has been implemented. Clinical physicians quickly used the workstations soon after the start of MDIS at MAMC. The major advantage for clinicians has been the amount of time saved when retrieving multimodality images for review. On the other hand, the radiologists have been slower in their acceptance of the workstation for routine use.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Image Processing, Computer-Assisted , Radiology Information Systems , Computers , Hospitals, Military , Humans , Local Area Networks , Quality Assurance, Health Care , Quality Control , Radiology/education , Reproducibility of Results , WashingtonABSTRACT
Portal verification images were generated from the photon contamination in electron beams produced by a linear accelerator during treatment of patients receiving high-energy electron radiation therapy (8-14 MeV). An experimental storage phosphor system was used to record the images and display them on laser-printed film. Images were obtained from four or more treatment fractions from 21 cases of head and neck cancer. Precision in field placement was estimated by determining the position of a selected anatomic landmark relative to the center of the field for each series of images. The average standard deviation in the field-position measurements was 3.8 mm. Several procedural problems were also detected and corrected after review of the verification images. The results indicate that the emphasis placed on monitoring and control of field-positioning error in high-energy electron treatments should be similar to the emphasis placed on this aspect of error in photon treatment.
Subject(s)
Head and Neck Neoplasms/radiotherapy , Radiotherapy, High-Energy/standards , Electrons , Humans , Particle Accelerators , Quality Assurance, Health Care , Radiotherapy, High-Energy/methodsABSTRACT
An experimental high-contrast sensitivity storage phosphor imaging system was used to produce double-exposure localization portal images of abdominal and pelvic treatment fields. The images were contrast enhanced by using an analog windowing technique and edge enhanced with a digital unsharp masking routine. A laser printer was used to print the storage phosphor images onto film. Conventional images were obtained by placing film in the cassette with the storage phosphor plates prior to exposure. Four radiation oncologists rated the storage phosphor and conventional films for perceptibility of anatomical detail needed to verify the placement of the treatment field. Contrast enhancement alone did not result in a significant improvement in perceptibility over unprocessed conventional film (p greater than 0.20). However, the combination of contrast and edge enhancement did result in a significant improvement over conventional film (p less than 0.05).
Subject(s)
Image Enhancement/methods , Radiotherapy/methods , Humans , Radiographic Image Enhancement , Technology, RadiologicABSTRACT
Portal verification images were generated by the photon contamination in electron beams produced by a linear accelerator during treatment of patients receiving high-energy electron radiation therapy. Both conventional and storage phosphor methods yielded projection radiographs in which anatomy of the irradiated and surrounding tissue was demonstrated. Exposed phantoms were used to confirm that the images represent a true projection of the radiation field. A preliminary series of 22 cases was evaluated by two radiotherapists and judged subjectively to be of clinical value. Geometric error, or more importantly, the lack thereof, during high-energy electron treatments was easily confirmed with this method. In three cases, the treatment protocol was corrected based on the images obtained. Because the readout process of storage phosphor images allows for gain adjustments and post-processing, the images obtained with this method were found to delineate anatomy in the treated and surrounding tissues somewhat more consistently than could conventional images.
Subject(s)
Electrons , Luminescent Measurements , Radiotherapy, High-Energy , Humans , Particle Accelerators , Technology, RadiologicABSTRACT
Two drawbacks in quality of portal radiographs in radiation therapy are their low contrast and low spatial resolution. These are due to the low differential absorption of body tissues at therapeutic energies and to a relatively large radiation source. We used an experimental, high-contrast sensitivity storage phosphor imaging system (Eastman Kodak Co.) to produce portal images. The system consists of a storage phosphor detector, a high-contrast sensitivity laser scanner (12 bit), an image processing module, and a laser printer (12 bit). Patients undergoing radiation therapy treatments had both a conventional portal image and a storage phosphor image taken. Both were displayed side-by-side and were evaluated independently by three radiotherapists according to quality of information to verify the treatment field. Each of the three radiotherapists rated the storage phosphor images to be better (p less than 0.001) than the conventional images. However, rated improvements of low-contrast storage phosphor images of the pelvis and abdomen (40) were significantly lower than those of high-contrast (head, neck, and chest) images (53).
