Computational Tool for Calculation of Tissue Air Ratio and Tissue Maximum Ratio in Radiation Dosimetry

Abstract

In radiation therapy, it is essential to calculate the dosimetric quantities such as Percentage Depth Dose (PDD), Tissue Air Ratio (TAR), and Tissue Maximum Ratio (TMR). The basic depth dose data was determined by dosimetric measurements taken in dummy patients (phantoms), which have density nearly equal to human body tissues, with ionization chamber placed in them [1]. A system for absorbed dose calculations has been developed to foresee the depth dose distribution in patients going to be treated. The radiation dose deposited by ionizing radiations within the patient or medium varies with the varying depth. This variation is due to different parameters like depth, beam energy, field size, Source to Surface Distance (SSD). While calculating absorbed doses, greater considerations must be given to these parameters as they cause changes to depth dose distributions [2]. Plenty of radiotherapy units, such as linac and cobalt-60 units, accomplish the treatment of cancerous parts. To treat cancerous tissues, cobalt 60 gamma ray beam is used for more than fifty years in radiotherapy [3].