Exposure to ionizing radiation in the emergency department from commonly performed portable radiographs.

To accurately assess the potential hazard of exposure to ionizing radiation from portable radiographs taken in the emergency department, a study was performed to measure such radiation at different distances from the edge of an irradiated field during portable cervical-spine (pC-S), portable chest radiograph (pCXR), and portable anteroposterior-pelvis (pAP-pelvis) radiographs. For all three types of portable radiographs, radiation exposure is a function of distance from the beam. However, at 40 cm (15 inches) away from the beam during a pC-S or pCXR and at 160 cm (63 inches) from a pAP-pelvis film, exposure is minimal. At these distances one would need to be exposed to more than 1,200 such radiographs to equal background environmental ionizing radiation. Medical personnel should not have to leave a patient care area for fear of undue acute and chronic radiation exposure while portable radiographs are performed in the ED. By using protective garments and standing appropriate distances away from the patient, continuous patient care can be maintained while portable radiographs are taken in the ED.

A nine-year evaluation of emergency department personnel exposure to ionizing radiation.

Emergency department personnel experience potential occupational hazards from exposure to ionizing radiation (x-rays). To assess this risk, ionizing radiation exposure was analyzed during a nine-year period for 128 ED personnel. The group consisted of 21 physicians, 92 nurses, and 15 ancillary personnel. Exposure was measured for both penetrating and nonpenetrating radiation using standard film dosimeter badges. Film badge use compliance was 66.7% for physicians, 86.2% for nurses, and 86.7% for ancillary personnel. Penetrating radiation exposure averaged 0.12 mrem/month for physicians, 0.70 mrem/month for nurses, and 0 mrem/month for ancillary personnel, all less than the average natural background exposure. We concluded that if standard radiation precautions are taken, the occupational risk from ionizing radiation exposure to personnel in the ED is minimal, and that routine monitoring of radiation exposure of ED personnel is unnecessary.

Excretory urography using computed radiography.

A computed radiographic system for generating digital film images was evaluated in the performance of excretory urography. Three experienced radiologists reviewed digital and conventional screen-film urograms for 100 patients in a prospective study to evaluate the clinical utility of the digital system. Results indicate no difference between digital and screen-film urograms in diagnostic sensitivity, specificity, or receiver-operating-characteristic curves for differentiating normal from abnormal studies. Readers' performances in making specific diagnoses were also the same with both techniques.

Licensing criteria for nuclear medicine.

The use of radioactive materials in medicine is one of the most highly regulated areas the physician has to deal with. There are three basic types of licenses for use of radioactive material defined in the Code of Federal Regulations (CFR), chapter 10, part 35. These are the general license, which is mainly applicable to small volume in vitro work; the specific license, which is used in most medical facilities; and the broad license, which is suited for larger research-oriented practices. Licensing requires proof of competence of the user and of adequate provision for protection of public health. Materials used in medicine are grouped for convenience into three diagnostic categories and two therapeutic categories. A sixth group, for sealed implants, is not generally applicable in nuclear medicine. Training and experience of users may be documented in a number of ways, including board certification in nuclear medicine. Therapeutic applications require additional proof of direct personal experience. The radiation safety officer is a pivotal individual in the licensing procedure, being directly responsible for carrying out the highly detailed requirements for protection of personnel and patients. A radiation safety program based on the "as low as reasonably achievable" (ALARA) concept requires personal monitoring, inventory control, detection and control of contamination, and strict adherence to licensing rules. Training of personnel and proper maintenance of equipment and facilities are also vital parts of the licensing process. The requirements of licensing and for renewal are clearly spelled out by the various regulatory agencies and require meticulous record keeping with documentation that all prescribed procedures have been followed and duly recorded.

Transportation issues in nuclear medicine and the release of radioactivity into the environment.

Large volumes of radioactive materials are shipped daily over the nation's highways, by air, and by other transportation modes for a variety of purposes. These shipments include those intended for nuclear medicine applications. Shipments are governed by the Federal Department of Transportation, the Nuclear Regulatory Commission, and, for international shipments, the International Atomic Energy Agency. Knowledge of the regulations of these agencies is essential for maintenance of a viable radiation safety program. The use of radioactive materials is invariably accompanied by the potential for release of radioactivity into the environment. This potential is addressed in the recommendations and regulations of several voluntary and governmental agencies. Recently, new concepts have been introduced into these recommendations and regulations that use the concepts of "annual limit of intake," "committed effective dose equivalent," and "derived air concentrations." These concepts improve the applicability of present standards for the release of radioactive materials into the environment and for the protection of individuals from these materials.

Myocardial uptake of thallium-201 augmented with bicarbonate: concise communication.

Sodium bicarbonate was used to enhance the myocardial concentration of Tl-201 in rabbits and dogs. Organ distribution studies in rabbits and in vivo imaging in dogs showed a 1.5-2 fold increase in myocardial Tl-201 concentration in bicarbonate-treated animals as compared with matched controls. Image improvement was noted, with threefold enhancement of myocardium-to-liver ratios. The results suggest that a similar improvement may be possible for clinical myocardial imaging.

Computer processed 99mTc-DTPA studies of renal allotransplants.

In order to refine the diagnostic possibilities of the radionuclide renal study in transplanted patients and to compensate for the nonspecificity of the 131I-hippuran study in some situation, 99mTc-DTPA WAS USED SIMULTANEOUSLY FOR IMAGING AND TIME-ACTIVITY CURVES. For these curves to be significant, appropriate background subtraction had to be made with a simple computer-processing method. The results obtained have shown that it is possible to distinguish marked acute tubular necrosis from milder degrees, thus affording a prognostic index in the immediate postoperative period, when the hippuran data are often nonspecific. Further, the diagnosis and follow-up of acute rejection episodes can be improved by the DTPA processed curves. Although these curves when examined individually do not show a specific pattern for rejection, they may reveal striking evolutionary changes when compared to the previous studies, even when the hippuran curves are unchanged. The physiologic basis for the differences between the two time-activity curves may be related to the differential handling of the two radiopharmaceuticals by the kidney.