Cytogenetic monitoring of hospital workers occupationally exposed to ionizing radiation using the micronucleus centromere assay.
(1/54)
A cytogenetic study was performed in lymphocytes of hospital workers occupationally exposed to X- and gamma-rays using the micronucleus centromere assay. A comparison of the data for the exposed group and an age-matched group of non-exposed hospital workers showed a significant (P < 0.05) increase in centromere-positive micronuclei for the radiation workers, while no effect on centromere-negative micronuclei was present. The observed systematic increase in micronucleus frequency with age was mainly due to increased chromosome loss, reflected in the centromere-positivity of the micronuclei. The micronucleus frequencies were 40% higher in females than in males, which can again be attributed to higher chromosome loss. Two exposed individuals showed exceptionally high micronucleus yields, 90% of which were centromere-positive. In situ hybridization with a centromeric probe for chromosome X shows that X chromosome loss is responsible for these high micronucleus yields. In the studied population, smoking had no significant effect on the micronucleus yields. The results obtained indicate that in contrast to the predominantly clastogenic action of acute exposure to ionizing radiation, the aneugenic properties of radiation may be important after long-term chronic low dose exposure. (+info)
Scattered radiation during fixation of hip fractures. Is distance alone enough protection?
(2/54)
We measured the scattered radiation received by theatre staff, using high-sensitivity electronic personal dosimeters, during fixation of extracapsular fractures of the neck of the femur by dynamic hip screw. The dose received was correlated with that received by the patient, and the distance from the source of radiation. A scintillation detector and a water-filled model were used to define a map of the dose rate of scattered radiation in a standard operating theatre during surgery. Beyond two metres from the source of radiation, the scattered dose received was consistently low, while within the operating distance that received by staff was significant for both lateral and posteroanterior (PA) projections. The routine use of lead aprons outside the 2 m zone may be unnecessary. Within that zone it is recommended that lead aprons be worn and that thyroid shields are available for the surgeon and nursing assistants. (+info)
Ionising radiation exposure to orthopaedic trainees: the effect of sub-specialty training.
(3/54)
INTRODUCTION: We monitored image intensifier use by orthopaedic trainees to assess their exposure to ionising radiation and to investigate the influence of sub-specialty training. MATERIALS AND METHODS: Five different orthopaedic registrars recorded their monthly image intensifier screening times and exposure doses for all cases (trauma and elective), for a combined total of 12 non-consecutive months. Radiation exposure was monitored using shoulder and waist film badges worn both by surgeons and radiographers screening their cases. RESULTS: Registrars in spinal sub-specialties were exposed to significantly higher doses per case and cumulative doses per month than non-spinal trainees (P < 0.05), but significantly lower screening times per case (P < 0.05). There were no significant differences in cumulative screening times per month (P > 0.05). Regression analysis for all surgeons showed a significant relationship between shoulder film badge reading and cumulative dose exposed per month (P < 0.05), but not for cumulative screening time. Shoulder film badge recordings were significantly higher for spinal compared with non-spinal registrars (P < 0.05), although all badges were below the level for radiation reporting. Only one radiographer badge recorded a dose above threshold. CONCLUSIONS: Whilst the long-term effects of sub-reporting doses of radiation are not fully understood, we consider that this study demonstrates that trainees should not be complacent in accepting inadequate radiation protection. The higher doses encountered with spinal imaging means that sub-specialty trainees should be alerted to the risk of their increased exposure. The principle of minimising radiation exposure must be maintained by all trainees at all times. (+info)
Directly measured secondhand smoke exposure and COPD health outcomes.
(4/54)
BACKGROUND: Although personal cigarette smoking is the most important cause and modulator of chronic obstructive pulmonary disease (COPD), secondhand smoke (SHS) exposure could influence the course of the disease. Despite the importance of this question, the impact of SHS exposure on COPD health outcomes remains unknown. METHODS: We used data from two waves of a population-based multiwave U.S. cohort study of adults with COPD. 77 non-smoking respondents with a diagnosis of COPD completed direct SHS monitoring based on urine cotinine and a personal badge that measures nicotine. We evaluated the longitudinal impact of SHS exposure on validated measures of COPD severity, physical health status, quality of life (QOL), and dyspnea measured at one year follow-up. RESULTS: The highest level of SHS exposure, as measured by urine cotinine, was cross-sectionally associated with poorer COPD severity (mean score increment 4.7 pts; 95% CI 0.6 to 8.9) and dyspnea (1.0 pts; 95% CI 0.4 to 1.7) after controlling for covariates. In longitudinal analysis, the highest level of baseline cotinine was associated with worse COPD severity (4.7 points; 95% CI -0.1 to 9.4; p = 0.054), disease-specific QOL (2.9 pts; -0.16 to 5.9; p = 0.063), and dyspnea (0.9 pts; 95% CI 0.2 to 1.6 pts; p < 0.05), although the confidence intervals did not always exclude the no effect level. CONCLUSION: Directly measured SHS exposure appears to adversely influence health outcomes in COPD, independent of personal smoking. Because SHS is a modifiable risk factor, clinicians should assess SHS exposure in their patients and counsel its avoidance. In public health terms, the effects of SHS exposure on this vulnerable subpopulation provide a further rationale for laws prohibiting public smoking. (+info)
A pilot study of the validity of self-reported ultraviolet radiation exposure and sun protection practices among lifeguards, parents and children.
(5/54)
Sensitivity characteristic that uses optical filters in GafChromic radiation dosimetry.
(6/54)
GafChromic EBT film (GC-EBT) is lower in sensitivity than ready-pack film. The purpose of this study was to increase GC-EBT sensitivity by using band-pass filters and a polarized light filter. The filters were inserted between the GC-EBT and the scanner bed and digitized. We evaluated the sensitivity characteristic, amount of noise, and the dose corresponding to noise. When only the band-pass filter was inserted, a filter of transmission wavelength peak at 600 nm showed the maximum sensitivity. When a filter of 600 nm in transmission peak at wavelength was combined with a polarized light filter, sensitivity improved. There was no increase in the amount of noise according to the type of filter. The dose corresponding to noise increased as the quantity of light after passing through the filter decreased. When a suitable band-pass filter for the absorption peak of GC-EBT was used, it was suggested to be able to improve sensitivity without increasing noise. (+info)
Sunlight exposure assessment: can we accurately assess vitamin D exposure from sunlight questionnaires?
(7/54)
The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant, the correlation coefficients for the relation between personal report of sun exposure and ambient UV light measured by dosimetry (assessment of radiation dose) are relatively low. Moreover, the few studies to assess the relation between sunlight measures and serum 25-hydroxyvitamin D show low correlations. These low correlations may not be surprising given that personal factors like melanin content in skin and age also influence cutaneous synthesis of vitamin D. In summary, sunlight exposure questionnaires currently provide imprecise estimates of vitamin D status. Research should be directed to develop more objective, nonintrusive, and economical measures of sunlight exposure to quantify personal vitamin D status. (+info)
Agreement between diary records of time spent outdoors and personal ultraviolet radiation dose measurements.
(8/54)