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Radioimmunological estimation of prostatic acid phosphatase was carried out in 72 reference subjects, 46 patients with benign prostatic hypertrophy, 106 patients with untreated prostatic carcinoma and 25 patients with a carcinoma of some other origin. The mean concentration in non-acidified serum was 1.3 +/- 0.4 (M +/- SD) ng/ml for the reference group and 1.6 +/- 0.8 ng/ml for the benign hypertrophy group. The upper limit of discriminatory values for the diagnosis of prostatic carcinoma was fixed at 3 ng/ml. Taking this value, the overall percentage of positive results for carcinoma of the prostate was 61% (65/106). The number of cases with a value greater than 3 ng/ml was 3/18 (17%) for stage A, 8/27 (30%) for stage B, 7/13 (54%) for stage C and 47/48 (98%) for stage D. 8% (2/25) of carcinomas of another origin gave a positive result. The results of estimation using the radioimmunological technique were compared with those obtained by the measurement of enzyme activity using para nitro-phenyl phosphate as a substrate in 34 untreated prostatic carcinomas (all stages mixed together). When measurements by both techniques were carried out under the same ideal conditions using fresh sera as soon as possible after the blood was drawn, the result was abnormal in 10 cases out of 12 (83%) for the radioimmunological method and in 8 cases out of 12 (67%) for the measurement of enzyme activity. By contrast, under routine conditions, the positive percentage figures were 77% (17/22) for the radioimmunological technique and only 36% (8/22) for the measurement of enzyme activity. It would thus appear that radioimmunological measurement is more reliable than the measurement of enzyme activity.

Meta-iodobenzylguanidine was synthesized, radiolabelled with I 131 or I 123 and injected to 28 controls and 7 patients totalling 13 foci of pheochromocytoma. The tumour was located in one adrenal gland in 3 cases, in both adrenal glands in 1 case, and between the aorta and the vena cava in 1 case; 2 were malignant with metastases. Scintigraphy was negative in all controls, whereas all pheochromocytomas were clearly demonstrated 24 h after injection, except one regarded as non functional due to necrosis. By comparison, CT readily showed the tumour in 7 cases, showed it only thanks to scintigraphic guidance in 4 cases and failed in 2 cases. It is concluded that scintigraphy with meta-iodobenzylguanidine provides a safe and reliable means of locating a wide range of pheochromocytomas.

Angioscintigraphy, performed on 50 patients suspected of aortic aneurysm and complemented by abdominal ultrasonography in 31 cases, disclosed: -- Three cases of thoracic aortic aneurysm, 2 of which were confirmed by arteriography and surgery. It was impossible to perform surgery in the third case, no arteriography was done. Strict agreement with standard thoracic images had made the angioscintigraphic diagnosis seem correct. -- Twenty-seven cases of abdominal aortic aneurysms confirmed by arteriography or surgery. Ultrasonography disclosed an abdominal aortic aneurysm in 26 cases, 20 of which were confirmed. The agreement of the two procedures in 10 unconfirmed cases (6 positive and 4 negative diagnoses) led us to consider the diagnosis as correct. Angioscintigraphy appears to be a reliable procedure for detecting thoracic and abdominal aortic aneurysms. Ultrasonography is the simplest and least costly procedure for study of abdominal aortic aneurysms.