Study of whole-body occupational radiation exposure in the industrial radiography in Bangladesh

Objective:In order to understand the complete scenario of the effectiveness of radiation protection practice in the workplace,especially in the industrial radiography and also to analyze the trends with other related studies,epidemiological studies and legal purposes,the assessment and register of the effective dose plays a significant role.Therefore,efforts have been given in the assessment of collective effective dose,mean effective dose,prediction of lifetime cancer risk,and contribution of different age group workers in the collective effective dose.Methods:The occupational radiation exposures for 472 workers were investigated in industrial radiography throughout Bangladesh from 2015 to 2018 by using thermoluminescent dosimeter(TLD).By using a Harshaw TLD reader(Model-4500),the effective dose was measured in a quarterly basis throughout the year.Based on the value of personal dose equivalent Hp(10),database was prepared and recorded.Results:The collective effective dose was 36.1,40.7,28.8 and 37.5 man⋅mSv among 105,102,100 and 165 radiation workers in 2015,2016,2017 and 2018,respectively.The maximum effective dose received by radiation workers was 6.0,7.1,6.9 and 19.9 mSv in 2015,2016,2017 and 2018,respectively,which remained within the stipulated dose limits imposed by Nuclear Safety and Radiation Control(NSRC)Rules-1997,Bangladesh and International Commission on Radiological Protection(ICRP-103).Conclusion:This kind of monitoring would help to construct a national database that will be used by the end users to improve their implementation of optimization in occupational radiation protection in industrial radiography.

Measurement of Gamma-Rays Using Smartphones

The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment.