Kajian pemantauan dosis neutron terhadap pekerja radiasi pada pengoperasian Linac dengan energi foton ≥ 10 MV

The use of Linac for radiotherapy is starting to use a lot of high-energy photons of 10 MV; in addition, some use 15 MV for patient therapy in routine use, there is also the use of 6 MV. The purpose of this study is to obtain an overview and information of the neutron dose that has the potential to provide additional doses for radiation workers operating the Linac 10 MV aircraft. Based on the Regulation of the Head of BAPETEN No. 3 of 2013, Article 48 paragraph (2) states that in the operation of Linac with X-ray photon energies above 10 MV, must coat the shield wall with a neutron-absorbing material. The statement follows the IAEA-TecDoc 1891 that neutrons will have the potential to have a significant radiological impact on workers if routinely operated at energies above 10 MV, so must consider protection for workers. The results of a survey from 27 hospitals, obtained information through filling out questionnaires and discussions and validated with B@LIS Pendora, it found that the trend of annual doses received by each profession in the operation of Linac 6 MV, 10 MV, and 15 MV was less than one mSv, only partially small worker dose that is above one mSv (above the 90th percentile). This study concluded that the presence of neutrons in Linacs up to 10 MV was deemed not to have a significant radiological impact on workers. The recommended criteria/mechanism for monitoring worker neutron doses in Linacs up to 10 MV could be based on if the safety study results obtained a dose received by workers 1.5 mSv/year. Then, there is no need to monitor the neutron dose. If the measurement results of exposure to neutron and gama radiation around the Linac space are 7.5 microSv/hour, there is no need for neutron monitoring. In Linacs above 10 MV, if the annual effective dose is 1.5 mSv/year, there is no need to monitor the dose of special neutron personnel. Still, routine radiation exposure monitoring may be considered every two years. Keywords: Neutron Dose, Radiation Worker, Linac, Dose Monitoring.

Radiological impact assessment of different building material additives

In this study, samples of building material additives were analyzed for naturally occurring radioisotope activity such as uranium, radium, and radon. The radon exhalation and the annual effective doses, were also calculated. The activities of the samples, were determined using HPGe gamma spectrometry and ionization detector. The results were used to calculate dose values by using RESRAD BUILD code. The activity concentration of the samples ranges between 9–494 Bq/kg Ra-226, 1–119 Bq/kg Th-232 and 24–730 Bq/kg K-40. In conclusion the investigated samples can be used safely as building material additives as they do not pose a major risk to humans.

Radiological Impact Assessment of Class 3 Landfill of TENORM Waste from Tin Industry in Bangka Island

This study assessed the potential radiological impact of a class 3 landfill as a disposal facility of the final tin slag from the tin industry in Bangka Island. Tin slag that contains TENORM (Technically Enhanced Naturally Occurring Radioactive Material) with activity concentrations above exemption level limits should be stored safely and securely. The radiological impact analysis of storing TENORM waste was carried out before and after the construction of a landfill facility. RESRAD OFFSITE version 3.2 software was used to simulate dose and cancer risk, and analyze the contribution of exposure pathways. Radionuclide concentration, landfill facility specifications, hydrogeological data, climatological data, and food and water consumption data were used as input parameters of RESRAD. The receptor was a resident farmer who lives 100 meters from the facility, grows his own food, and consumes water from his land. The total dose before and after the construction of the landfill were 3.13 mSv/year and 1.84×10-2 mSv/year while cancer risks were 5.69×10-3 and 6.50×10-5, respectively. The exposure pathways from inhalation of radon become a major contributor to dose acceptance and cancer risk. Based on these results, the landfill facility is effective in reducing the potential impact of radiological hazards from dose acceptance and cancer risk.

Monitoring of radionuclides in water for human consumption in the county of Angra dos Reis

The radiological impact for members of the population living in Angra dos Reis- RJ was assessed using environmental monitoring data from radium, lead, uranium, thorium and cesium in water for human consumption. For this, were collected and analyzed by radiometry (134Cs and 137Cs), radiochemical (226Ra, 228Ra and 210Pb) and mass spectrometry with inductively coupled plasma (238U and 232Th). From the results, it was observed that the concentrations found were lower than the values established by CONAMA, WHO and the Ministry of Health. It was concluded that the presence of these radionuclides in the collected waters is natural and with levels that are not harmful to health.