Health Physics

No abstract text is available yet for this article.

After considering epidemiological studies on the induction of cataracts in individuals exposed to radiation, the International Commission on Radiological Protection recommended, in 2012, a reduction in the annual eye-dose limit of occupationally exposed workers. This imposed higher performance demands on existing dosimetry systems and the development of new dosimetry technologies. The operational quantity to be measured is Hp(3), the personal dose equivalent at a depth of 3 mm in an ICRU 4-element tissue cylinder 20 cm in height and 20 cm in diameter...

Radiation exposure is a primary concern in emergency response scenarios and long-term health assessments. Accurate quantification of radiation doses is critical for informed decision-making and patient care. This paper reviews the dose reconstruction technique using both X- and Q-bands, with tooth enamel as a reliable dosimeter. Tooth enamel, due to its exceptional resistance to alteration over time, offers a unique opportunity for assessing both acute and chronic radiation exposures. This review delves into the principles underlying enamel dosimetry, the mechanism of radiation interactions, and dose retention in tooth enamel...

In Canada, leukemia is diagnosed at a rate of 15 cases per 100,000 persons and accounts for about 3% of all new primary cancers. In this study, geographical correlation between residential radon exposure and leukemia incidence was investigated at a provincial level with more accurate long-term radon measurement data in 21,330 homes and 10-y (2000-2009) age standardized incidence rates per 100,000 population for various subtypes of leukemia. The analyses showed that the incidence rate of non-Hodgkin lymphoma is statistically significantly correlated with average indoor radon (222Rn) concentration for Canadian females (p = 0...

The Human Monitoring Laboratory (HML) at Health Canada updated its whole-body counter with four new electrically cooled HPGe detectors. To optimize the counting efficiency of the new system, Monte Carlo simulation was used to model the whole-body counter using a reference BOMAB male phantom. The resulting modeled counting efficiencies showed that the best position to install the four new detectors could be obtained without performing laborious real measurements, thereby reducing the cost of preparing the BOMAB phantoms and reconfiguring the detector arrays in multiple geometries, saving time and energy...

It is now well accepted that the mechanisms induced by low-dose exposures to ionizing radiation (LDR) are different from those occurring after high-dose exposures. However, the downstream effects of these mechanisms are unclear as are the quantitative relationships between exposure, effect, harm, and risk. In this paper, we will discuss the mechanisms known to be important with an overall emphasis on how so-called "non-targeted effects" (NTE) communicate and coordinate responses to LDR. Targeted deposition of ionizing radiation energy in cells causing DNA damage is still regarded as the dominant trigger leading to all downstream events whether targeted or non-targeted...

The Human Monitoring Laboratory, Health Canada (HML), has used a 3D printer to re-engineer its Lawrence Livermore National Laboratory (LLNL) foam lung sets (manufactured by Radiology Support Devices, Inc., Long Beach, CA). The foam sets are currently the HML standard for calibrating and performance testing lung-counting systems in Canada. This paper describes the process of creating and validating new 3D-printed lung sets modeled from one of the HML's existing RSD foam sets. The existing sets were custom made, making them costly and difficult to obtain or replace...

Ontario Tech University (University of Ontario Institute of Technology) is one of Canada's newest universities, having been incorporated in 2002. In 20 y, the University has increased enrollment from a few hundred students to over 10,000. The University was designed to be "market driven" and as such offered courses that had high market demand. The Faculty of Energy Systems and Nuclear Science was one of the first faculties to be established at the University, with the intent to fill a gap between personnel that were retiring out of the nuclear industry and the dearth of nuclear engineers and health physicists being educated in Canada...

Previous studies have shown that measuring changes in electrical impedance that follow radiation-induced suppression of metabolic activity in irradiated yeast cells can be used to determine radiation dose. The current work investigates the radiation response of Saccharomyces cerevisiae cells by using metabolic activity of cells as a damage indicator. Impedance biodosimetry was examined as a method to evaluate the radiation response of yeast cells. Active lab-grade dry yeast cells were used as the biological material as these samples are simple to handle and have a long shelf-life...

The performance of a LaBr3(Ce) gamma spectrometer at high count rates was investigated up to an input count rate of 1.3 Mcps. In order to make its pulse processing faster, a preamplifier provided by the detector manufacturer was eliminated, and the signal from the photomultiplier tube was fed directly to a digital pulse processing system. To accomplish both fast pulse processing and good energy resolution, the pulse-shaping parameters were optimized at a low count rate of 1.5 kcps, and then measurements were carried out at various count rates...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

Proton therapy is an advanced method for treating cancerous tumors, and its adoption has expanded significantly in recent years. The production of high-energy protons, however, may result in the creation of secondary neutrons and gamma rays. Hence, ensuring radiation safety at proton therapy centers is crucial, with shielding playing a vital role. This study aimed to evaluate the efficacy of the shielding implemented at the Provision Proton Therapy center in Knoxville, TN, USA. For this purpose, we measured and compared gamma ray radiation levels within the treatment room and the facility's roof...

Concerns have been raised about the possibility of effects from exposure to short wavelength light (SWL), defined here as 380-550 nm, on human health. The spectral sensitivity of the human circadian timing system peaks at around 480 nm, much shorter than the peak sensitivity of daytime vision (i.e., 555 nm). Some experimental studies have demonstrated effects on the circadian timing system and on sleep from SWL exposure, especially when SWL exposure occurs in the evening or at night. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has identified a lack of consensus among public health officials regarding whether SWL from artificial sources disrupts circadian rhythm, and if so, whether SWL-disrupted circadian rhythm is associated with adverse health outcomes...

The resuspension of radioactively contaminated particles in a built environment, such as from urban surfaces like foliage, building exteriors, and roadways, is described empirically by current plume and dosimetry models used for hazard assessment and long-term risk purposes. When applying these models to radiological contamination emergencies affecting urban areas, the accuracy of the results for recent contamination deposition is impacted in two main ways. First, the data supporting the underlying resuspension equations was acquired for open, quiescent conditions with no vehicle traffic or human activities, so it is not necessarily representative of the urban environment...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

A comprehensive search was performed to examine the literature on diagnostic reference levels (DRL) for computed tomography (CT) and radiography examinations that are performed routinely in Jordan. EBSCO, Scopus, and Web of Science were used for the search. The acronym "DRL" and the additional phrase "dose reference levels" were used to search for articles in literature. Seven papers that reported DRL values for radiography and CT scans in Jordan were identified. One study reported DRLs for conventional radiography, two studies reported CT DRLs in pediatrics, and the remaining four studies provided DRL values for adult CT scans...