Surface activity following administration of radioactive phosphorus.

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Soon after radioactive phosphorus became available for medical research, it was found that the uptake following administration to animals or man is greater and more rapid in metabolically active tissue, such as regenerating liver, bone marrow, spleen, and malignant tumors, that eventually it becomes widely distributed, with its greatest concentration in bone, and that the labeled phosphorus is retained longer in neoplastic tissues than in equally active normal tissues (5, 6, 11). The radiophosphorus was found in higher concentration in the nuclei of normal or neoplastic cells than in the cytoplasm (1, 21, 22), and within the nuclei most of the p32 was in the nucleoprotein (16). It was concluded that the higher specific activity and turnover in tumor tissue was related to increased mitotic activity. By assaying weighed amounts of tissue, it was shown that the uptake in neoplastic breast tissue was two to seven times that in normal breast tissue, while lymph nodes with metastases were three to four times more active than normal nodes (7). Studies were extended to the measurement of activity on the surface of the skin, and it was reported that one case of melanoma and two cases of mycosis fungoides showed increased activity over the involved areas, compared to normal areas (15). LowBeer and his co-workers (13), carrying out systematic surface measurements of beta activity after administration of P32, reported increased surface activity over a limited number of a wide variety of superficial and subcutaneous lesions, both neoplastic and inflammatory. In a series of 41 malignant breast tumors subsequently reported (17), they found at least 25 per cent higher activity over the involved breast than over the normal, following intravenous administration of P32. These results suggested the possibility of a simple technic for differentiating benign from malignant breast tumors, and for determining the existence of lymph node metastases. It seemed possible that, after a suitable period following the administration of radiophosphorus, one could measure the beta activity on the skin compared to an uninvolved area, and thus diagnose a malignant process. An obvious objection is that the very short range of the P32 beta particles in tissue may make the observed activity dependent on the thickness of the overlying tissues. Nevertheless, because of the simplicity and rapidity of the suggested technic, the present study was undertaken to evaluate its diagnostic possibilities for superficial lesions. Attention has been limited to superficial lesions, since it is virtually impossible to detect by surface observations beta activity arising at a depth of more than 5 mm. Selection of Cases This report presents the results of surface measurement of beta activity on 30 patients (see Tables I and II). For the study of surface activity over lymph nodes, patients were selected with obvious superficial lymph node metastases, axillary or supraclavicular, or both.