Source of Support: None, Conflict of Interest: None
Bllis concept of NSD was developed into TDF&CRE for normal tissues and into TSD for cancer control for the conventional treatments of one fraction a day. Recently linear quadratic (LQ) model has been applied for not only to the late and early effects on normal tissues but also to the cancer control. In order to improve the efficacy of radiotherapy for advanced cases of cancer, multifraction treatments a day (MDF) have been tried and are found to be successful in most of the cases. Dale has extended the linear quadratic model to the multifraction treatments a day and derived equation for relative effectiveness (RE) for 2,3 and many fractions a day. However, the variables of. < /P and p are not known for various tissues. Supe et al. have attempted to derive formulations for CRE and TSD for multifraction treatments a day. In order to test the applicability of these concepts to multifraction treatments a day, prospective studies were undertaken at Gandhi Medical College Hospital, Bhopal on patients of cancer of head Et neck region. . The data about normal tissue reactions and the tumour regressions fitted well with the values of CRE and TSD respectively. Taking values of o< /P as 10 Gy for normal tissue early effects as well 6s tumour regressions and P = .32h-' the LQ model also predicts better curability of tumour by MDF.