A report on results of 186 32P tests is given. Radiation increases of more than 30%, compared with tumor-free areas, were considered as positive. 95 eyes were histologically examined. The 32P test gave 90 correct positive answere and 1 correct negative answer. Faulty positive results were found in 2 cases; faulty negative results were also found in 2 cases. This means that the diagnosis was correct in 95%. The literature is discussed concerning reliability and methods. The dangers of the use of 32P are stressed, and the development of noninvasive nuclear-medical diagnostic methods is suggested.