INTERNAL HEPATIC RADIOTHERAPY: I

Abstract

Metastatic cancer of the liver is a disease that once clinically established can only be treated with palliative results, with rare exceptions, and has been reported in 64 percent of patients originally operated for cure. It was proposed to treat the disease with a prophylactic dose of internal irradiation using colloidal Cr32PO4. Results in rats showed that with an intravenous isotope injection the bone marrow has a high uptake of the 32CrPO4 ; however, when injected by the enteric intra-arterial method the amount of bone marrow Cr32PO4 uptake is approximately one-third that of the intravenous route. This difference is significant as the bone marrow is a radiosensitive organ. The enteric intra-arterial injection method accomplished the basic goals of homogeneous distribution of radioactivity within the liver, with a low level of systemic radioactivity, except in the spleen, and no evidence of radiation hazard to environment or attendants. The distribution of the radiation within the liver is also critical because the effective distance that the beta particles from the 32P travels is only 3 mm. It can be seen that if an even distribution is not obtained, there may be areas which receive little or no irradiation, hence any malignant cells inmore » such an area will not be treated and may continue to grow. Both the intra-arterial and intravenous route give homogeneous distribution, as shown in autoradiographs. The intraportal vein route, while having the lowest bone marrow uptake, had an unacceptable nonhomogeneous distribution. The method described produces localized, concentrated irradiation within the liver, and except for the spleen, spares other organs from high radiation dose. The results are predictable and reproducible.« less