Widespread bone metastases can occasionally give rise to a uniform distribution of 99Tcm methylene diphosphonate resulting in a superficially normal appearance on the bone scan. The scans are recognizable by the high ratio of bone to soft tissue activity, the absence of focal lesions in the axial skeleton, and there are usually no renal images. These "superscans" can occasionally be misinterpreted as normal. An index of image quantitation related to the ratio of bone to soft tissue uptake is shown to be capable of clearly distinguishing these patients from patients in other categories. The condition is thought to be more frequently associated with prostatic carcinoma than with other aetiologies.

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Bone scanning with 99mTc-Sn-HEDP, radiographic skeletal survey and determination of plasma acid and alkaline phosphatase values were carried out in a consecutive series of 90 untreated patients with carcinoma of the prostate. 99mTc-Sn-HEDP provided satisfactory bone imaging and was convenient in use. The addition of bone scanning to radiographic survey increases the detection rate of skeletal metatases by 16%. Radiography increases the accuracy of bone scanning by identifying false positive scans due to benign disease and false negative scans when there are diffuse symmetrical bony metastases. The plasma phosphatases alone are less accurate staging tests. The acid phosphatase data support the validity of scan positive--X-ray negative findings. Bone scan abnormalities due to secondary deposits usually precede elevation of plasma alkaline phosphatase.

1. Plasma oxalate has been measured by a radioisotopic method applicable to all concentrations of plasma oxalate and renal function, and also by an enzymatic method which was only applicable to raised concentrations of plasma oxalate. 2. Where the two methods could be applied simultaneously, the agreement between them was good. 3. Plasma oxalate was 86% ultrafiltrable at concentrations of up to 44 micromol/l. 4. Oxalate clearance and the exchangeable oxalate pool were also measured. The ratio of oxalate clearance to creatinine clearance was greater than unity in most normal subjects and patients. 5. These methods were used in normal subjects and in patients with primary hyperoxaluria and/or chronic renal failure. A raised plasma oxalate concentration was found in both conditions. Chronic renal failure is probably the most common cause of a raised plasma oxalate.

SummaryExperience with x-rays, strontium-87m scintigraphy, and technetium-99m polyphosphate scintigraphy in the identification of bone metastases in 201 patients with prostatic cancer is reviewed. About 40% of the patients had demonstrable metastases in bone at the time of first presentation.Comparative studies of 247 x-ray and B?mSr surveys indicated that x-rays failed to detect metastases in 10% of cases where they were identified by B7mSr but that the isotopic survey similarly failed to detect radiologically evident deposits in 7% of cases.Similar studies comparing 99mTc polyphosphate surveys with x-ray scans showed that x-rays missed isotopically detected metastases in 12% of cases, but in only one survey out of 67 did the isotope miss radiologically evident deposits. In a series of 32 patients investigated by both isotopic techniques 'mTc polyphosphate did not fail to detect any metastases and Identified deposits in one patient in whom they were missed by 87mSr scintigraphy. About 15% ofboth x-ray and s7mSr surveys gave equivocal results, but only 3% (2 out of 67) of "mTc polyphosphate surveys were equivocal.We concluded that 9 mTc polyphosphate bone scintigraphy with the gamma camera was the most reliable of the techniques used for the identification of bone metastases in patients with carcinoma of the prostate. The results of scintigraphy with s7mSr suggested that serial surveys may provide early evidence of hormone resistance in prostatic cancer.