Assessment of natural radioactivity concentration in the soil samples from the Churchandpur and Ukhrul districts of Manipur, India.

The natural radioactivity concentration was studied for 40 soil samples of the Churchandpur and Ukhrul districts of Manipur, India, by using gamma-ray spectroscopy. The average radioactivity concentration of 226Ra, 232Th and 40K in Churchandpur was found as 39.9 (range: 30-56), 72.1 (range: 57-93) and 564.1 (range:360-867) Bq kg-1 respectively, whereas, in Ukhrul, average radioactivity for the same was found as 30.3 (range: 16-54), 54.2 (range:24-89) and 637.1(range:103-901) Bq kg-1, respectively. The calculated radioactivity parameters were compared with the world average values. The measured radium equivalent activity (Raeq), absorbed dose rate ($\dot{\mathrm D}$), annual effective outdoor dose(E) and the external hazard index (Hex) were observed as 165 (range: 63.7-234.8) Bq kg-1, 77.6 (36.9-108.0) nGy h-1, 0.11 (0.05-0.13) mSv y-1 and 0.5 (0.1-0.6), respectively. This study aims to provide baseline data for radionuclide present in the Churchandpur and Ukhrul districts of Manipur.

Assessment of natural radioactivity in the RCC building materials used in the valley region of Manipur, India.

An assessment of radioactivity concentration of reinforced cement concrete types of house was conducted in the valley region of Manipur, India. The average radioactivity concentration of 226Ra, 232Th, and 40K of portland cements are 39 (range: 32-52) Bqkg-1, 36 (range: 22-62) Bqkg-1, and 1812 (1254-2424) Bqkg-1; for concrete are 36 (range: 26-45) Bqkg-1, 65 (range: 45-86) Bqkg-1, and 660 (639-681) Bqkg-1; for sand are 45 (30-61) Bqkg-1, 114 (range: 55-212) Bqkg-1, and 1859 (range: 1413-2232) Bqkg-1; and for bricks are 30 (range: 24-37) Bqkg-1, 148 (range:79-184) Bqkg-1, and 1444 (range: 1093-2103) Bqkg-1, respectively. The annual effective dose was observed with an average value of 1.9 (range: 0.9-3.3) mSvy-1. However, gamma index was observed with an average value of 1.1 (range: 0.5-2.0).

Evaluation of variation in dose of organs at risk in intracavitary brachytherapy of cervical cancer - a prospective study.

PURPOSE: The aim of this work was to evaluate the variation of dose in organs at risk (OARs) in fractionated high dose rate intracavitary brachytherapy (HDR-BT) for cervical cancer. MATERIAL AND METHODS: A prospective study was carried out on 20 cervical cancer patients treated with fractionated (HDR-BT). International Commission on Radiation Units and Measurement (ICRU) bladder (bICRU) and rectum (rICRU) points were defined according to ICRU Report 38, using two orthogonal radiograph images taken by Simulator (Simulix HQ®) and prospectively kept to less than 80% of prescription dose to point A during real treatment planning process using the Plato Sunrise Treatment Planning System®. RESULTS: The average variation of individuals in estimated doses of OARs in the inter fractional as well as in a single fraction were 2.4% and 0.7% of point A for rICRU, 4.3% and 1.6% for bICRU, and 0.8% & 0.2% for point B, whereas point A itself was found to be 1.6% & 0.6%. CONCLUSIONS: Average variation of the delivery of dose per fraction was found well within the recommended limit. The study observed smaller variation of doses to OARs which could present better reproducibility of geometry of (HDR-BT) applicators and its relative displacement with critical structures. Transportation of patient from simulator room to treatment room causes small uncertainties in delivery dose.

The rectum and bladder doses in intracavitary brachytherapy for cervical cancer.

PURPOSE: The aim of this work was to study the International Commission on Radiation Unit and Measurement (ICRU) for rectum (rICRU) and bladder (bICRU) dose behaviors in the treatment of cervical cancer by high dose rate (HDR) intracavitary brachytherapy (ICRT). MATERIAL AND METHODS: A retrospective study was carried out on 38 patients with a total of 38 fractions (1st fraction of each patient) of cervical cancer treated with HDR intracavitary brachytherapy in addition to external radiotherapy (EBRT). Manchester system using standard source loading pattern were used in the planning. Normal distributions were tested to the rICUR and bICRU doses for any statistical conclusions. RESULTS: It was observed that rICUR and bICRU of the population under study is found to show normal distribution at 5% level of probability with mean dose of 65% and 61% and standard deviation of 15% and 21%, respectively. CONCLUSIONS: The normality behavior of the rectal and bladder doses suggests that not less than 80% of population (patients) receive rectal and bladder doses less than 80% of the prescribed dose at point A.