Measurement of Radioactive Phosphorus in Breast Tumors in Situ; a Possible Diagnostic Procedure

Radioactive phosphorus administered orally or intravenously in the form of disodium hydrogen phosphate solution is assimilated by different tissues in varying degrees. The concentration in tissues at any given time after administration depends on the metabolic activity of constituent cells. In general, malignant growths have a higher metabolic rate than the tissues from which they originate, and regenerating tissues also show greater metabolic activity than normal tissues. In both types of growth, therefore, a greater amount of phosphorus is taken up for the new cells that are forming. The differential distribution can be determined quantitatively by measuring the radioactivity of ashed samples of the tissues by means of a beta-ray electroscope, an electrometer, or by a Geiger-Müller counter. Such a determination necessitates the removal of the tissues in part or in whole.

If a lesion is located in the skin or close beneath the skin, the beta rays emanating from the disintegrating phosphorus atoms localized in the lesion should penetrate the tissues and come through into the air in sufficient number to be readily detected by a Geiger-Müller counter placed on the skin. Marinelli (1), in 1942, reported measuring such rays with a Geiger-Müller counter on three patients, one with a melanoma and two with mycosis fungoides. One of the present writers (Low-Beer), using a similar method, found increased activity not only over such skin lesions as mycosis fungoides, squamous-cell and ulcerating basal-cell carcinomata, psoriasis, eczema, and cutaneous Hodgkin's disease, but also over subcutaneous lesions, such as lymphosarcoma in lymph nodes, cervical node metastases from transitional-cell carcinoma of the nasopharynx, bone metastases in the skull from carcinoma of the lungs, and others.

These findings suggested the investigation of the uptake of radioactive phosphorus in human breast tumors in order to determine, first, whether the differential concentration of phosphorus in such tumors could be detected by surface measurements, and second, whether or not it would be feasible to distinguish preoperatively between benign and malignant breast tumors by such surface measurements. It was thought that the same method might indicate the presence or absence of metastatic lesions in the axilla or supraclavicular area. To determine these points we studied patients with breast tumors prior to surgery. The measurements were made with bell-jar type Geiger-Müller counters with thin glass windows having a diameter of 1.5 to 2.5 cm.

Each patient was given from 300 to 500 microcuries of radioactive phosphorus intravenously in the form of isotonic disodium hydrogen phosphate solution, twenty-four or forty-eight hours before operation. Two, four, six, and twenty-four hours following injection, surface measurements were made directly over the palpable breast tumor and over comparable areas on the opposite normal breast and other fleshy parts of the body.