Source of Support: None, Conflict of Interest: None
A combination of moderate doses of external beam irradiation and intraluminal irradiation has been found to give the best results in esophageal cancer. In advanced cases, with massive local disease the purpose of moderate doses of external beam irradiation is to shrink the local tumour so that intraluminal irradiation is possible in 2-3 weeks. We give 35 Gy / 15 fractions in 3 weeks by external beam and 12 Gy calculated at 1.0 cm from the centre of the source axis in two sessions of 6 Gy each, a week apart by HDR intraluminal irradiation. In this report, the various formulae necessary to calculate the effective biological dose by CRE. TDF and LQ models have been outlined when the combined modality is used for therapy.