Radiology, Vol 119, 209-213, Copyright © 1976 by Radiological Society of North America
Time, dose and volume factors in interstitial Radium implants of carcinoma of the oral tongue
KK Fu, EK Chan, TL Phillips and JW Ray
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.
