PubMed HealthSearch

PubMed · 2228622

Source inventory limits.

Abstract

A new set of values has been developed for exempting sealed sources of radioactive materials from inventory. The criteria for exemption are: (a) the annual occupational dose from external radiation at 1 m from the source is approximately 100 microSv (10 mrem) or less; and (b) the source activity is approximately equal to the annual limit on intake by inhalation or less than 4 X 10(7) Bq (1000 microCi). These criteria were selected to correspond to an annual occupational dose of approximately 50 to 500 microSv (5 to 50 mrem) and a small potential annual risk of approximately 1 X 10(-6) to 1 X 10(-5) fatal cancers or less.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G D Kerr, K F Eckerman. 1990. Source inventory limits.. https://doi.org/10.1097/00004032-199012000-00018

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Shielding performance and clinical applicability of lead-free materials in computed tomography.

Owing to the high radiation exposure associated with computed tomography (CT) examinations and the image quality degradation caused by conventional radiation shielding materials, this study evaluated the dose reduction performance and image quality maintenance potential of a newly developed lead-free composite shielding material. This material was composed of bismuth, tungsten, tungsten carbide, aluminium, and polyurethane. Phantom-based dose measurements demonstrated that the shielding material achieved dose reduction rates ranging from 17.6% to 37.6%, depending on tube voltage. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and changes in tube current-time product (mAs) under a scout-based automatic exposure control (AEC) protocol were analysed according to the presence or absence of the shielding material across regions. For the clinical evaluation, CT scans were performed on four patients. Furthermore, the images were reviewed to evaluate whether this material affected image quality. The shielding material exhibited radiation reduction levels comparable to those reported in previous studies. SNR and CNR analyses showed minor statistical variations in certain regions; however, most differences were not statistically significant, and even significant differences remained within a range that did not compromise diagnostic image quality. Under the scout-based AEC protocol, the use of the shielding material resulted in less than 1% variation in mAs values. No visually perceptible artefacts or clinically significant image quality degradation were observed. The proposed composite shielding material demonstrated the potential to mitigate some limitations of conventional shielding materials and showed preliminary clinical feasibility as an adjunctive strategy for radiation dose reduction in CT examinations.

Radiation Protection

Summary statements from the Third Conference on Radiation Protection and Dosimetry.

The Third Conference on Radiation Protection and Dosimetry was conducted in Orlando, FL, on 21-24 October 1991. At the end of the conference, each member of the Technical Program Committee summarized the events considered to be of particular importance. Subjects discussed included dosimetry accreditation programs, regulations, standards, compliance, advances in dosimeters and instrumentation, training, needs in metrology, and funding of dosimetry research. These statements have been collected and combined and are presented as a brief summary of the conference.

Radiation Protection