Individual Dose Levels Research Articles

Information on cosmic radiation received by Belgian aircrew: a survey.

Exposure of aircrew to cosmic radiation had already been identified as an issue of concern in the European BSS of 1996 which requested airlines to assess the exposure of the crew and to inform their workers of the health risks their work involves. These requirements have been implemented in Belgian regulations in 2001 and updated with the transposition of the 2013/59/Euratom directive. Dosimetry data show that aircrew is the group of workers, which contributes the most to the collective dose of occupationally exposed workers in Belgium. In order to verify the extent of the information received by Belgian aircrew regarding their exposure to cosmic radiation, FANC, the Belgian radiation protection authority, launched in 2019 a large survey in collaboration with the Belgian Cockpit Association (BeCA), the professional association representing airline pilots in Belgium. The survey included 8 questions regarding the information of aircrew on cosmic radiation in general, on the individual dose level and on the risk related to exposure during pregnancy. A total of about 400 responses to the survey were received. Overall, the survey reveals that aircrew members in Belgium receive too little information about the potential risks, that they are not sufficiently informed about their own exposure and that female staff members are insufficiently informed about the hazards for the unborn child in case of pregnancy, and 66% of the respondents answered that their employer has never informed them about their exposure to cosmic radiation. However, most are aware of this phenomenon, either because they have looked up information or because they have discussed the topic with colleagues and professional associations. The results also showed that 17% of female crew continued to fly while being pregnant. Finally, the survey also allowed to identify differences and similarities between different groups of workers: cockpit and cabin crew, men and women. For instance, cabin crew was even less informed about their individual exposure than cockpit crew.

Analysis on monitoring results of individual dose of occupational external radiation among radiation workers in Lanzhou in 2019

Objective: To analyze the individual dose level of occupational external radiation of radiation workers in Lanzhou in 2019, so as to provide reference for radiation protection and occupational health management. Methods: In April 2020, a total of 1460 radiation workers in Gansu Provincial Center for Disease Control and Prevention in 2019 were selected as the research objects. The unit nature, hospital level and occupational category of the monitored workers were collected, and the monitoring results of external radiation personal dose in 2019 were analyzed and compared. Results: In the occupational external radiation monitoring of radiation workers in Lanzhou in 2019, the effective dose of 48 persons was 1.0~<5.0 mSv, the effective dose of 2 persons was 5.0~<10.0 mSv, the annual collective effective dose was 308.21 people·mSv, and the average annual effective dose of monitored persons was 0.21 mSv/a. There was significant difference in the distribution of annual effective dose per capita among different occupational groups (H=34.43, P<0.05) . The annual effective dose per capita of nuclear medicine personnel was higher (0.56 mSv/a) , followed by interventional radiology (0.33 mSv/a) . The ratio of annual collective dose to total annual collective dose with annual individual dose more than 5 mSv (SR(5)) and the ratio of the number of staff with annual individual dose more than 1mSv to the total number of monitored personnel (NR(1)) were higher in nuclear medicine and interventional radiology personnel. The average annual effective dose distribution of diagnostic radiologists in different level hospitals was statistically significant (H=16.46, P<0.05) . The average annual effective dose in private hospitals, community hospitals and health centers was higher (0.32 mSv) , followed by county hospitals (0.23 mSv) . Conclusion: The individual dose of occupational external radiation of radiation workers in Lanzhou is generally low, and the annual effective dose of nuclear medicine and interventional radiology workers is high. The management of radiation protection should be emphasis on this people. And it is suggested to strengthen the supervision of private hospitals and update and maintain the equipment of community health centers.

Results and analysis on individual dose level of occupation exposure in industrial application in China (2009-2013)

Objective: To understand and analyze the individual dose level of occupational external exposure of industrial workers in China from 2009 to 2013, and to provide basic data and scientific basis for radiation protection and radiation protection management. Methods: Since January 2009, the individual dose monitoring data of industrial workers were collected through the "National radiological health information platform-individual dose monitoring system". The methods of Kruskal-Wallis test and the Mann-Whitney test were used for statistical analysis of monitoring results for different occupational categories from 2009 to 2013. Results: From 2009 to 2013, a total of 151, 541 people were monitored for the number of industrial radioactive workers, showing a steady upward trend year by year. The average annual effective doses was 1.179 mSv/a. The average annual effective dose of industrial flaw detection, industrial irradiation, luminescent coatings, radioisotope production, logging, accelerator operation and other applications were 0.808, 1.429, 0.315, 1.074, 0.766, 0.576, and 1.510 mSv/a. There was a statistically significant difference in the average annual effective dose between the seven occupational categories (P<0.05) . The average annual effective doses of other application and industrial irradiation workers in 2013 were significantly higher than other occupational categories (P<0.05) . Conclusion: The average annual effective dose of industrial radiation workers meet the requirements of national standards. The exposure doses of industrial radiation and other application radiation workers are relatively high. The radiation protection workplace protection measures should be further improved and improved, and radiation protection knowledge training should be strengthened to protect their occupational health.

Analysis of individual dose monitoring results among radiation workers in a first-class hospital at Grade 3 from 2010 to 2017

Objective: To understand the occupational external exposure dose among radiation workers in a first-class hospital at Grade 3 of Suzhou, and to provide reference for radiological protection. Methods: The individual dose of 1156 radiation workers in the hospital from 2010 to 2017 were detected, the annual collective effective dose and per capita annual effective dose were analyzed for different years, different occupations (diagnostic radiology, radiotherapy, nuclear medicine, interventional radiology) , gender, and age. Results: From 2010 to 2017, the total annual collective effective dose was 351.40 person·mSv, the per capita annual dose was 0.30 mSv/a, and radiation workers whose annual effective dose was less than 1 mSv accounted for 94.98%. There were 5 interventional radiology workers and 1 nuclear medicine worker with annual effective dose between 2 and 4 mSv. There was no worker with annual effective dose over 4 mSv. The per capita annual effective dose of nuclear medicine workers was the highest (0.40 mSv/a) . The per capita annual effective dose was not significantly different between radiation workers with different genders and ages (P>0.05) . Conclusion: Most of radiation workers have low individual dose level in the hospital. It is important to focus on nuclear medicine workers and interventional radiology workers.

Radiation exposure levels of routine SPECT/CT imaging protocols

AimsTo assess incremental and total patient exposure from clinical SPECT/CT imaging by means of effective dose estimations with regards to different protocols and SPECT/CT systems. Materials and methodsConsecutive patient exposure levels were documented prospectively from SPECT/CT operations at three European imaging centers. Documentation included the volume-weighted computed tomography (CT) dose index, the CT dose length product (DLP) and the amount of applied radiopharmaceutical. SPECT/CT examinations were categorized regionally into head, neck, myocardium, thorax, abdomen, extremities and whole-body. Effective dose from the CT (EDCT) was estimated from the DLP using gender specific conversion factors. EDSPECT was estimated from the injected activity levels and corresponding conversion factors (ICRP 106). ResultsThis study included 678 SPECT/CT examinations. EDCT per indication and EDSPECT per tracer ranged from 0.01mSv to 7.4mSv and from 1.1mSv to 12.2mSv, respectively. In general, EDSPECT contributed most to overall patient exposure. Total EDSPECT/CT averaged across all protocol categories was 6.7mSv. ConclusionTotal patient exposure from clinical SPECT/CT is 7mSv on average. Individual dose levels vary with the clinical indication and on-site protocol parameters.

Steep dose gradients for simultaneous integrated boost IMRT

Steep dose gradients between two planning target volumes (PTVs) as may be required for simultaneous integrated boosts (SIB) should be an option provided by IMRT algorithms. The aim was to analyse the geometry of the SIB problem and to implement the results in an algorithm for IMRT segment generation denoted two-step intensity modulated radiotherapy (2-Step IMRT). It was hypothesized that a gap between segments directed to the inner and the outer PTV would steepen the dose gradient. The mathematical relationships were derived from the individual dose levels and the geometry (diameters) of the PTVs. The results generated by means of 2-Step IMRT segments were equivalent or better than the segment generation using a commercial IMRT planning system. The dose to both the inner and the outer PTV was clearly more homogeneous and the composite objective value was the lowest. The segment numbers were lower or equal – with better sparing of the surrounding tissue. In summary, it was demonstrated that 2-Step IMRT was able to achieve steep dose gradients for SIB constellations.

Statistical analysis of historical occupational dose records at a large medical center.

Routine monitoring of occupational radiation exposure is done primarily to demonstrate compliance with dose limits. Statistical analysis of past and present dose records provides a useful tool in the management of institutional radiation safety programs. In this study, a statistical analysis of annual dose records from 1985-1999 from a large tertiary care medical center with a cyclotron and radiopharmaceutical production facility is performed. A total of 6,089 annual dose records, categorized into ten occupational groups, were included in the analysis. Dose distribution is skewed, with 85% of workers receiving an annual dose of less than 1.0 mSv, while 1.3% have doses > or =10 mSv. The mean annual dose of all monitored workers during this 15-y period ranged from 0.5 to 1.2 mSv. Large variation in the mean annual dose exists among the different occupational groups. Four occupational groups were identified as relatively highly exposed, namely cyclotron and radiopharmaceutical production, cardiac catheterization, nuclear medicine, and diagnostic radiology. These four occupational groups also showed different trends in the mean annual dose. A correlation study showed that total annual collective dose has no linear association with the number of monitored workers, the number of measurably exposed workers, or the number of workers with annual dose between 0.1 to <10 mSv. Moderate correlation (r = 0.64) was observed between the annual collective dose and the collective dose of workers with an annual dose between 0.1 to <10 mSv. A strong and significant correlation (r = 0.95) exists between the total annual collective dose and both the number of workers with annual dose of > or =10 mSv and the corresponding collective dose due to these highly exposed workers. Although the fraction of these highly exposed workers is small (about 1%), they have a significant impact on the total collective dose and their contribution can be as high as 50%. Workers with annual dose of > or =10 mSv tend to concentrate in a few identified occupational groups and not across all occupational groupings. The cyclotron and radiopharmaceutical production department is of particular concern due to its high individual dose levels and increasing mean annual dose trend for the last 5 y. Radiochemists and cyclotron engineers tend to receive an annual dose exceeding the dose limit. A plot of the collective dose of highly exposed workers vs. the total collective dose shows that if a dose constraint of 10 mSv is imposed on highly exposed occupational groups, the total collective dose is expected to be about 200 person-mSv.

Quality control of pharmaceuticals containing clenbuterol by thermal lens spectrometry

An ultrasensitive absorptiometric procedure for the determination of clenbuterol in pharmaceutical preparations was developed. Clenbuterol was diazotized with nitrite and coupled with 1-(naphthyl)ethylenediamine, and the absorbance of the azo dye formed was measured by both spectrophotometry and ultrasensitive thermal lens spectrometry (TLS). The TLS limit of detection was 1.5 ppb, 14-fold lower than with a Hewlett-Packard diode array spectrophotometer. Thus, the TLS procedure can be advantageously applied to quality control of clenbuterol at the individual dose level and in small samples. Repeatability as relative standard deviation was 1.5% (50 ppb, n = 6).

Evidence of differential hematopoietic compensation to lead intoxication in blood, liver and kidney.

The dependence of fluorescent porphyrin levels on the concentration of lead in blood, liver and kidney has been examined as functions of both the level and duration of dosing. Individually housed male Wistar COBS rats of 200 g were randomly selected for 3, 7, 21 and 35 day dosing periods in groups of: control, 50, 100 and 1000 ppm dosing in drinking water. The plot of all data points for porphyrin concentration against measured lead burden covers the same range of levels and closely resembles the scatter of data observed in humans. However, subsets of this plot defined by individual dose levels and durations yield well-defined linear relationships. At all dose levels at 7 days the correlation of porphyrin concentration to lead tissue burden is negative in all tissues, showing a direct inhibition of hemopoiesis with lead burden. Depending on the tissue the slope becomes less negative, or, as in blood, positive at 21 and 35 days at all doses. This compensation is most rapid in blood, then liver and is least evident in kidney. The time at which compensation is observed is the same for all doses in each tissue and seems therefore, to depend on the rate of protein turnover in different tissue types. These results suggest that a direct correlation of porphyrin concentration to lead burden is not valid without knowledge of the dosing history. As well, evidence of compensation in one tissue does not imply successful compensation in other affected tissues where regeneration rates are slower.(ABSTRACT TRUNCATED AT 250 WORDS)