title: Time, dose and volume factors in interstitial Radium implants of carcinoma of the oral tongue.
abstract: In a retrospective computer dosimetry analysis of 58 patients with carcinoma of the oral tongue treated with interstitial radium implants alone or in combination with external irradiation, dose and volume appear to be the most important factors in both local control and the incidence of necrosis; in the dose rate range commonly used in clinical interstitial radiotherapy, dose rate has no significant effect. The optimal minimum tumor doses for local control vary with the size of the primary lesion: 6,000 rads for T1 lesions and 6,500 rads for T2 lesions treated with interstitial radium implants alone and 7,500 rads for lesions treated with interstitial radium implants in combination with external irradiation. For lesions treated with implants plus external irradiation, greater local control was achieved when most of the dose was delivered through the interstitial implants. For a given volume, the incidence of necrosis was directly proportional to the degree of overdosage; for a given dose, the incidence of necrosis was directly proportional to the volume receiving the dose.
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D003201:Computers; D006801:Humans; D010025:Osteoradionecrosis / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011883:Radium / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D011883:Radium