Intensity Modulated Radiotherapy (IMRT) is a modern type of external beam radiotherapy that conforms high radiation dose to the target with minimum dose to the organs at risk (OARs), making it an embellishment of every developed institution. The earlier publications didn't have much proofs of the clinical superiority of IMRT over other radiotherapy techniques. It was considered a complicated and expensive treatment technique but the advent of modern treatment and imaging modalities have made its rapid clinical implementation unquestionable. Now IMRT have grown up, it is not the technique in which non uniform beam intensities were generated just by metal compensators, now it has multileaf collimators (MLCs), rotational fan and cone beam delivery systems and robotic arm linear accelerators to cure the life threatening cancer diseases. IMRT with all its advances have some limitations including its high cost, increased staff work, increased time for its planning, and risks of marginal misses.

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Summary: In this paper we have tried to find the relationship of thermal and mechanical properties i. e. thermal conductivity, tensile strength and Young's Modulus of the composite material. Two systems were selected; poly(vinyl alcohol)/sodium sulphate composite, and poly(vinyl alcohol)/lithium sulphate composite. Various concentrations of these salts were used to make composites of poly(vinyl alcohol). Films were grown, dried at room temperature and were subjected to mechanical, structural and thermal characterization. Thermal conductivity was determined at room temperature using polyethylene, silicon and quartz as reference. It was found out that the thermal conductivity of both the systems is highly dependent on the nature and the concentration of added salt in the polymeric composite. Thermal conductivity of the poly vinyl alcohol/ sodium sulphate composite, and poly vinyl alcohol/lithium sulphate composite, decreased with concentration of the salts in the polymer composite. These composites were also analyzed by XRD. Observed roperties were explained on the bases of their structure. Machenical properties such as tensile strength and Young's Modulus were also found out to be a function of the compostion of the composite

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