There, are a few indigenously developed personal computers (PC) based treatment planning systems in India. They directly have many roles to play improve the quality of radiotherapy. In this paper, we present details of sources of inaccuracies that may arise in the PC based treatment planning systems and a few guidelines to correct them. From this study, it can be concluded that a thorough checking of the treatment planning systems is very much needed to know the limitations of the systems as well as the most appropriate ways in which the system can be used efficiently.

Advent of computerized tomography (CT) has revolutionized radiotherapy treatment planning (RTP). CT facilitates localization of tumour and normal tissues accurately. Multislice CT scanning produces a three dimensional matrix of information elements from which two dimensional images in any plane can be reconstructed and so can help in 3D treatment planning. Over the period, a number of important differences have emerged between diagnostic and therapeutic CT scans. The usefulness of CT scans for RTP is discussed and the technique followed at our institute for RTP using CT scans is presented.

Dosimetry in brachytherapy applications using Selectron remote after loading unit requires techniques which will help in planning the treatment. A simple method given here will prove useful for this purpose and also help the physicists in verification of these plans.

In the present investigation effect of gamma radiation on certain tissues (kidney, stomach and gills) of Heteropneustes fossilis Bloch, an Indian Cat fish, were studied. The fish were irradiated with 10 Gy of gamma radiations at the dose rate of 1.60 Gy/minute from a 6co source. Five fish were autopsied at each post-irradiation time of 1.2.3, 7.15 and 30 days. Radiation induced histopathology was observed in all the tissues studied. The radiolesions appeared on day-1 after exposure which became exaggerated on day-2 and 3. Signs of recovery were noticed on day - 7 which progressed on day-15 and normal histology was observed on day-30.

Evaluation of the performance parameters are needed to assure proper system performance and represent a valuable source of qualitative and quantitative data for routine quality control testing. The performance parameters that require regular evaluation in magnetic resonance imaging systems are discussed here. These parameters include the Resonance frequency, Magnetic field homogeneity, Image uniformity, spatial resolution, S/N ratio; Gradient linearity, Standard reference measurement, 1st & 2nd Echo artifacts and Echo intensities for spin echo measurements. The aim of the quality assurance is to detect deviations in the performance of the equipment well before they actually show up in the clinical images in the form of image artifacts or degraded images.

This paper deals with the designing aspects of central shielding block for external radiotherapy used in treatment of Ca Cx patients who are already treated or are going to be treated with ICR treatments. The designing aspects are discussed in detail particularly for the region between point A and point B.