Source of Support: None, Conflict of Interest: None
Check
Advanced cancers of head & neck when treated by the normal once a day treatment do not yield complete tumor control, Radio-biological research have predicted that the use of multiple fractions a day with dose per fraction of around 1 Gy would be an economic method of achieving better tumor control. The application of Linear Quadratic model to multifraction treatments a day was extended by Dale. He gave equations for Relative Effectiveness (RE) values for 2,3,4 fractions per day. These equations are quite complicated. Calculation of RE values from these equations is quite tedious and takes considerable amount of time if done on electronic calculators. Most of the hospitals in India do not have computers and hence these equations cannot be used for the evaluation of RE values. It was therefore, decided to undertake their evaluation and present them in the form of tables. It was found that the RE values decrease with the increase of inter-treatment interval. The values are found to increase with increase of repair half life. The RE value when plotted against a/p, forms a rectangular hyperbola. Further the RE values are found to be directly proportional to dose per fraction
