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Cancer, which is the uncontrolled division of cells, is a leading fatal disease in the world with high mortality rates. It can be treated using several methods, including radiotherapy, which involves ionizing radiation. Radiotherapy on the basis of source placement has two types, i.e. brachytherapy and external beam radiotherapy. External beam radiotherapy has evolved from 2-D conventional therapy to 3-D Conformal radiotherapy (3D-CRT) and then intensity-modulated radiotherapy (IMRT). Modern radiation therapy techniques such as IMRT improve dose conformity and sparing of organs at risk. Volumetric modulated arc therapy (VMAT) is a newly developed technique that uses treatment in arcs. In this report, a dosimetry comparison was performed between IMRT and VMAT. This study was conducted in the Radiotherapy Department of the Institute of Nuclear Medicine and Oncology Lahore (INMOL). Two types of cancer patients were selected for this comparison, i.e., five patients with Nasopharyngeal Carcinoma and ten patients with Prostate Carcinoma. Simulation of these patients was done with the help of a CT Simulator. The oncologists delineated all target volumes and organs. Then suitable fields/arcs were applied, which cover volumes effectively. This was followed by the optimization of plans for both techniques for every patient. Finally, evaluating parameters were compared, including volume coverage, conformity index, homogeneity index, organ doses, and monitor units. We obtained better results of target conformity indices from VMAT (1.16 and 1.25) than IMRT (1.24 and 1.30). VMAT was better in organ sparing too. Also, VMAT shows very few monitor units (468 and 733) as compared to IMRT (2325 and 2149). On the basis of the results obtained, it was concluded that VMAT is better than IMRT. This technique will enhance treatment efficiency as it takes less time to obtain the required results. Also, a very less scatter dose will be delivered to the patient.

The use of RAI-131 in thyroid carcinoma patients presents a special concern on the environmental radiation safety for those who come in contact with the patients especially after discharge from the facility because of excretion of I131 through perspiration, salivation, breathing and urination. Methods & Materials: The present study was conducted at Nuclear Medicine Oncology and Radiotherapy Institute Nawabshah (NORIN) Sindh from 2017 to 2021 with the objective to evaluate contamination hazards by Excretion made by thyroid cancer patients received iodine therapy stayed in isolation room with doses ranging from 80–200 mCi. The areas included corridor, sink, patient bed, and toilet bowl of isolation rooms before admission and after discharge using LAMSE RM-1001 survey meter. The minimum background radiation level measured before patient stay in isolation room was 0.07 μSv/h while the maximum was 0.40 μSv/h and the mean background reading was 0.18 ± 0.072 μSv/h. The maximum dose rate after discharge was observed at toilet bowl with mean of 9.69 ± 1.98 µSv/hr and minimum of 5.0 µSv/hr and maximum value 13.77 µSv/hr. The readings recorded for the sink were: 2.0 μSv/h minimum, 20.0 μSv/h maximum with a mean of 5.55 ± 1.57 μSv/h while those for the patient bed 0.41 μSv/h minimum, 6.92 μSv/h maximum and a mean of 2.83 μSv/h. the least dose rate was found in isolation room corridor (1.53 ± 0.78 μSv/h) with maximum and minimum values 0.28 & 3.20 μSv/h respectively. Radiation is harmful; safety measures must be ensured to minimize radiation exposure to the family members as well as community either during hospitalization or after discharge of RAI-131 patients. The radiation levels from toilet bowls, beds, sinks, and corridor of isolation rooms were well within the acceptable limits and hence, do not pose significant hazard to the public