A study on body phantom for improvement in dosimetry in modern radiotherapy techniques

Abstract

Purpose: A study on body phantom for improvement in dosimetry in modern radiotherapy techniques. newlineBackground: Radiation Physics is playing an important role in medicine since the discovery of x-rays (1895) and radium (1898). The treatment of cancer using radiation is being done since 1896 just after discovery of x-rays and the technological developments are still towards the peak. In current scenario the use of state of art technologies have made possible to deliver tumoricidal dose to target with minimal dose to the normal organs. In vitro dosimetric verification prior to patient treatment has a key role in accurate and precision radiotherapy treatment delivery. Modern radiotherapy practices, viz. three dimensional conformal radiation therapy (3DCRT), intensity modulated radiation therapy (IMRT), image guided radiation therapy (IGRT) and rapid arc therapy use complex set of filed portal and apertures and planned dose verification before treatment delivery becomes increasingly important. Most of the commercially available dosimetry phantoms have almost homogenous density throughout its volume. While real interior of patient body have variable and varying densities viz. soft tissue, bones and air cavities which are different from each other. This study has been done to develop and verify the physical Dosimetry in actual human body scenario. Also the effect of beam angles on planning dosimetric parameters has been studied. Before delivering the treatment plan, the patient position verification has a crucial role in the results of radiotherapy, similarly the phantom setup accuracy is main important part of dosimetry; small shift in phantom position may lead to false dose measurements compare to planned doses on TPS. This study has also covered the selection of suitable imaging technology. newlineMaterials and Methods: The 3DCRT and IMRT plans were generated on computed tomography (CT) images of patients with standard procedures by using 2 5 fields in 3DRT and 5 9 fields in IMRT. Photon energies of 6 mega voltage (MV) an