Medical Imaging Procedures Research Articles

CdTe detectors in medicine: a review of current applications and future perspectives

Abstract Cadmium telluride (CdTe) semiconductor sensors have been evaluated for medical applications for 15 years owing to their high stopping power, convenient energy resolution and operating conditions at room temperature. Most of the applications herein reviewed concern medical imaging procedures, i.e., nuclear medicine, including positron emission tomography and radiology with computerized tomography (XCT). Despite their attractive physical characteristics, their preliminary commercial development has been slowed down in the early 80s because of technical problems, particularly when large arrays were considered, and because of the competition with the more available and less expensive scintillators or xenon chambers which are still mounted in most modern medical imaging systems. Nowadays the characteristics of new materials have allowed the development of restricted but more specific domains of CdTe medical applications i.e. miniaturized nuclear probes dedicated to per-operative tumor detection or ambulatory monitoring of physiological (renal, cardiac) functions and bone absorptiometry using either planar or miniature tomographic systems. Supported by these features and encouraged by the growing competition between ionising and non-ionizing imaging modalities (US, MRI), research work is presently conducted with a view to using CdTe detectors in XCT.

A rotating tomographic imager for solar extreme-ultraviolet/soft X-ray emission

A concept is presented for a high-resolution EUV/soft-X-ray imager that has much in common with the medical imaging procedure of tomography. The resulting instrument is compatible with a simpler, less costly spin-axis-stabilized spacecraft. To demonstrate the fidelity of the reconstruction procedure, the observation and reconstruction is simulated to compare the results with the original image.

Trends in Radiation Protection of Medical Workers

Medical workers constitute the largest group of individuals occupationally exposed to radiation, and their collective dose equivalent is exceeded only by persons employed in the nuclear fuel cycle. Although medical workers have increased in number by about 50% over the past two decades, their collective dose has steadily declined. Factors that contribute to changes in the exposure patterns of medical workers include variations in demand for medical imaging procedures, changes in the way these procedures are administered to patients, and development of devices that utilize radiation more efficiently and display radiation-derived information more effectively. Trends such as the movement of imaging procedures into nonradiologic disciplines and nonhospital settings, and the imposition of economic and legal considerations into decisions about patient management and health care, may also ultimately affect the exposure of medical workers to radiation.

Rotating X-Ray Collimating Slit for Line-Scan Dual-Energy Medical Imaging

A rotating slit system has been designed and tested which can effectively translate a fan-shaped X-ray beam at the same average speed and in the same direction of travel as a patient moving continuously during a line-scan dual-energy medical imaging procedure. The slit has been shown to eliminate the artifacts due to bone in logarithmically subtracted images obtained with monochromatic X-ray beams derived from synchrotron radiation, where one beam is just above and the other just below the K-edge of iodine. Images of iodine-containing phantoms and in vivo canine images after intravenous iodine injection show vessel detail without artifacts due to bone. Corresponding images taken without the rotating slit have severe artifacts.