There has been significant progress in both the technological development of medical equipment and in the development of new therapeutic procedures in radiation therapy. As indiscriminate use of radiation without due caution may be harmful, it is necessary to ensure safety of radiation workers, patients undergoing diagnosis and treatment, public and environment. This paper presents the current status of the radiation therapy facilities in lndia and discusses the regulatory requirements for implementation of radiation protection, quality assurance procedures and type approval of equipment, personnel monitoring service for occupational workers; radiation safety related training programmes, and emergency preparedness and response measures.

The objective of this study is to compare the measured absorbed dose to water (D) between various protocols, such as IAEA TRS 398, TRS 381 and AAPM TG 51, for the clinical electron energies of 6,9, 12r15 and 18 MeV. Two cylindrical chambers, PTW 30001and NE 2571, and two plane parallel chambers, PTW Roos and PTW Markus chambers, were used. All chambers have been calibrated for 60Co quality, in terms of both absorbed dose (NDx) and air kerma (Nk), traceable to Secondary Standards Dosimetry Laboratory (SSDL), BARC, India. Absorbed dose- to- water ratios TRS 398/TG 51 and TRS 398/TRS 381 are graphically represented as a function of R 50. To study the difference in the absorbed dose to water, basic data from all the protocols are analyzed. In case of cylindrical chambers and plane parallel Roos chamber, maximum deviations of 0.7% between TRS 398 and TG 51 and 2% between TRS 398 and TRS 381 are observed. In the case of Markus chamber, maximum deviations of 1.8% between TRS 398 and TG 51 and 0.5% between TRS 398 and TRS 381 are obtained. Between TRS 398 and TRS 381, sources of variation are calibration factors such as & Ndx and Swak data. Though the difference between the protocols is not very significant, the change could be justified for the homogeneity in dosimetry.

The aim was to compare palliative radiotherapy regime 3000 cGy/l0F with a new regime 1750 cGy/5Ffollowed by a gap of 3 weeks and again 1750 cGy/5F with the help of L.Q. model and then correlating it clinically in cases of advanced head and neck cancer. Fifty patients were randomly assigned to either of the two regimes. Symptom palliation was same in both the arms but compliance was better in the new regime. Grade III mucositis and nausea occurred only in the first regime. This prospective randomized trial offers an alternative palliative regime, which may suit our remote rural patients.

We have treated 18 patients with surface mould brachytherapy, which includes 12 patients i.e. 66.67 % of intraoral cancers and remaining of other sites. The treatment of choice for localized lesions is electrons with intraoral cones in oral cancers. In absence of this facility one thinks of surgery or external radiotherapy. At our centre we have successfully treated these patients with surface mould using Selectron LDR and Ir-I92 sources. To adopt this technique it was required to have flexible applicators to suit the mould as well as surface anatomy of the tumor as it was not comfortable to use Selectron rigid applicator for all sites. Flexible applicator was designed and fabricated in the institute and is successfully used after proper calibration for the treatment purposes. We have achieved complete response in 15 patients i.e. 88.24% and partial response in 2 patients (11.76%). This technique was found comfortable, inexpensive, non invasive and helped in avoiding mutilating surgeries.

Brachytherapy delivers highly conformal radiation dose to the desired region of interest without causing excess dose to the surrounding normal organs. Of the established brachytherapy procedures, surface mould therapy is useful in sites, which are superficially placed and easily accessible. This form of treatment has been in routine use in the treatment of hard palate, chest wall and skin tumors. At our centre, we have used this method in the treatment of rare sites such as external auditory and Bowen's disease of peri-anal region. This paper describes the technical and physical aspects involved in the treatment of these sites.

Radiological investigations are very important in diagnosis of many ailments in spite of their known hazards. The knowledge of radiation doses received by the patients during radiological procedure is necessary and all efforts must be made to keep the radiation dose to its minimum level. In the present study, the author has measured the radiation doses received by the patients during various radiological procedures. 193 x-ray installations in udaipur division were visited and the patient radiation dosimetry was carried out using caSO4 : Dy thermoluminescence (TL) discs. It is observed that chest radiography is the commonest radiological procedure and accounts for 37% of all radiological investigations; 70% of the chest x-rays were normal without any pathology. The frequency of radiological procedures for Udaipur division was estimated and observed that, on an average, 537 radiological procedures are carried out per year for population of 100000, The contribution of per capita radiation dose due to radiological procedures over and above the natural background radiation dose works out to be 22 pGy / year. The detailed results are discussed in the present communication.