Study on the therapeutic effect of 32P chromic phosphate colloid on Lewis lung cancer in C 57 mice

To establish the model of Lewis lung carcinoma in C 57 nude mice, study the therapeutic effect of 32P chromic phosphate (32P -CP) colloid via an intratumoral injection and observe the effect of macroaggregated al-bumin (MAA). Methods: Rat model baring Lewis lung cancer was established. Intratumoral injections with 32P chro-mic phosphate colloids were performed to calculate the tumor reduction rate. 24 hours and 48 hours after the 32P-CP in-jection , the rat underwent a Bremsstrahlung planar study to achieve the ratio of the average radioactive counts of tumor site against non-tumor site (T/NT value). Superoxide dismutase (SOD) value in intratumoral fluid was measured with radioimmunoassay. Results:After treatment, the tumor size reduced apparently. Bremsstrahlung planar study showed significant radioactivity accumulation in tumor. Conclusion: We concluded that direct tumor intratumoral brachytherapy of 32 P-CP may achieve a high retention of radioactivity in tumor and persist for a long time. MAA-induced enhancement of 32P-CP radioactivity in tumor didnt occur in experimental Lewis lung cancer. SOD value could evaluate the therapeu-tic effect of 32P-CP brachytherapy.