This study aims to assess the adequacy level of radiological protection systems available in the diagnostic radiology facilities located in three capital cities of North East (NE) India. It further attempts to understand, using a multi-disciplinary approach, how the safety codes/standards in diagnostic radiology framed by the Atomic Energy Regulatory Board (AERB) and the International Atomic Energy Agency (IAEA) to achieve adequate radiological protection in facilities, have been perceived, conceptualized, and applied accordingly in these facilities. About 30 diagnostic radiology facilities were randomly selected from three capitals of states in NE India; namely Imphal (Manipur), Shillong (Meghalaya) and Guwahati (Assam). A semi-structured questionnaire developed based on a multi-disciplinary approach was used for this study. It was observed that radiological practices undertaken in these facilities were not exactly in line with safety codes/standards in diagnostic radiology of the AERB and the IAEA. About 50% of the facilities had registered/licensed x-ray equipment with the AERB. More than 80% of the workers did not use radiation protective devices, although these devices were available in the facilities. About 85% of facilities had no institutional risk management system. About 70% of the facilities did not carry out periodic quality assurance testing of their x-ray equipment or surveys of radiation leakage around the x-ray room, and did not display radiation safety indicators in the x-ray rooms. Workers in these facilities exhibited low risk perception about the risks associated with these practices. The majority of diagnostic radiology facilities in NE India did not comply with the radiological safety codes/standards framed by the AERB and IAEA. The study found inadequate levels of radiological protection systems in the majority of facilities. This study suggests a need to establish firm measures that comply with the radiological safety codes/standards of the AERB and IAEA to protect patients, workers and the public of this region.

PurposeThe aim of this study is to evaluate the decrease of biological equivalent dose and its correlation with local/loco-regional control of tumour in the treatment of cervical cancer when the strength of the Ir-192 high dose rate (HDR) brachytherapy (BT) source is reduced to single, double and triple half life in relation to original strength of 10 Ci (∼ 4.081 cGy x m2 x h−1).Material and methodsA retrospective study was carried out on 52 cervical cancer patients with stage II and III treated with fractionated HDR-BT following external beam radiation therapy (EBRT). International Commission on Radiation Units and Measurement (ICRU) points were defined according to ICRU Report 38, using two orthogonal radiograph images taken by Simulator (Simulix HQ). Biologically effective dose (BED) was calculated at point A for different Ir-192 source strength and its possible correlation with local/loco-regional tumour control was discussed.ResultThe increase of treatment time per fraction of dose due to the fall of dose rate especially in HDR-BT of cervical cancer results in reduction in BED of 2.59%, 7.02% and 13.68% with single, double and triple half life reduction of source strength, respectively. The probabilities of disease recurrence (local/loco-regional) within 26 months are expected as 0.12, 0.12, 0.16, 0.39 and 0.80 for source strength of 4.081, 2.041, 1.020, 0.510 and 0.347 cGy x m2 x h−1, respectively. The percentages of dose increase required to maintain the same BED with respect to initial BED were estimated as 1.71, 5.00, 11.00 and 15.86 for the dose rate of 24.7, 12.4, 6.2 and 4.2 Gy/hr at point A, respectively.ConclusionsThis retrospective study of cervical cancer patients treated with HDR-BT at different Ir-192 source strength shows reduction in disease free survival according to the increase in treatment time duration per fraction. The probable result could be associated with the decrease of biological equivalent dose to point A. Clinical end point of this study is more significant from double half life reduction of original source strength.

PurposeThe 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 methodsA 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®.ResultsThe 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%.ConclusionsAverage 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.

In order to elucidate the type of trap distribution in borate glass we have analyzed a set of glow peaks around 110°C recorded with different doses of β-ray irradiation. The glow curves are subjected to the rigorous Computerized Glow Curve Deconvolution (CGCD) both in the framework of kinetic formalism and differential equation formalism to judge which type of trap distribution favors in borate glass. It is observed that the distribution of traps is exponential, which is also well supported by standard error analyses i.e. Figure Of Merit (FOM) and Chi-square (χ2) test.

PurposeThe 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 methodsA 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.ResultsIt 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.ConclusionsThe 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.