Head and Neck Radiotherapy with Tele-Cobalt Machine- Efficacy and Need for Tissue Compensation

Abstract

External Beam Radiotherapy EBRT remains the mainstay for radical treatments in malignancies in head and neck regions Head and Neck malignancies form around of radiotherapy patients in the north eastern parts of the Indian subcontinent Because of less inter field separations the penetration requirements of the treatment plans makes the telecobalt beam sufficient for executing radiotherapy with proper immobilization and use of wedges if required Inter field thickness variations and irregular contour affect uniformity in delivered doses and adverse reactions are encountered because of skewed isodose curves seriously affecting the volume dose variations in treatment planning Normal tissue reactions affect effectiveness of the treatment and therefore deter the Quality of Life QOL EBRT with a telecobalt machine Theratron C started in and completed a decade at our centre About patients per day receive radiotherapy for head and neck treatments To overcome skin reactions and excess dose due to small contour of neck a need was felt to introduce tissue compensation Ellis type tissue compensation using cm thick Aluminum metal is introduced The tissue deficiency is measured by an L shaped gridded type Lucite frame work For individual patients the custom type compensator tray is prepared on a Lucite plate mountable in the shadow tray of the cobalt machine The attenuation coefficient of metal rods mu cm cm Al cm water A simple type of POP immobilization is prepared in place of thermoplastic immobilization shell The Lucite mounting tray has attenuation about Lateral opposing fields with compensation reduced resultant isodoses and in neck and chin levels to with uniform tumor volume homogeneous dose of Portal radiographs with and without compensator showed uniform tissue irradiation also a method to verify field positions If this method is applied to all the head and neck radiotherapy patients both for AP PA and Lateral fields the morbidity upto epidermis and overdose effects could be brought down making telecobalt treatments more effective In the era of high technology radio therapy these types of innovations at hospital level promote cost effective radical treatments to cancer patients because cancer care all over the globe becomes unaffordable