S. E.M. Clarke

Studies on the preparation and isomeric composition of 186Re- and 188Re-pentavalent rhenium dimercaptosuccinic acid complex.

The preparative conditions for 186Re(V)DMSA and 188Re(V)DMSA (DMSA = meso-dimercaptosuccinic acid), β-emitting radiopharmaceuticals that have been shown to localize in medullary thyroid carcinoma, require modification depending on the amount of carrier rhenium and the chemical form and medium in which the rhenium is supplied. Preparative conditions are described for use with carrier-free 188ReO4- in saline, and for use with 186ReO4- in saline, sodium hydroxide or nitric acid. Preparation of 186Re(V)DMSA (carrier present up to 2 mg per 2.5 ml reaction volume) requires a DMSA:SnCl2:Re ratio of 10:5:1 at 100 °C for 30 min. Addition of excess nitric acid or hydrochloric acid up to a concentration of 155 HIM does not reduce the yield from 100%. A commercial DMSA kit vial (e.g. Amerscan DMSA) can be used for preparation of 188Re(V)DMSA (carrier free) provided the required activity is in a volume of less than 1 ml per vial. A convenient method of concentrating the 188Re generator eluate to the required volume is described.

The value of bone scintigraphy in the evaluation of osteoporotic patients with back pain

We evaluated the role of bone scintigraphy in 60 osteoporotic patients with back pain. Thirty-four had scintigraphic evidence of vertebral fracture and were found to have a significantly lower bone density compared to those without fractures (p = 0.01). In only 14 patients was vertebral fracture considered to be the sole cause of pain with 38 having alternative abnormalities, the most common of which was facet joint disease (n = 30). Results of bone scintigraphy influenced a direct change in management in 18 patients and were able to exclude vertebral fracture as a cause of symptoms in 30. In symptomatic osteoporotic patients the bone scan may be helpful in elucidating the etiology of back pain and can impact on patient management.

Synthesis and characterization of [186Re]rhenium(V)dimercaptosuccinic acid: A possible tumour radiotherapy agent

[186Re]Re(V)DMSA, a beta-emitting analogue of the tumour imaging radiopharmaceutical pentavalent [99mTc]Tc(V)DMSA of possible value in tumour therapy, is readily prepared by stannous reduction of [186Re]ReO4 in the presence of dimercaptosuccinic acid at 100 degrees C using a commercial DMSA kit as used for renal imaging with 99mTc, and purified using a disposable sample preparation column. The complex has been identified as [ReO(DMSA)2] by NMR, optical and i.r., spectroscopy and elemental analysis.

An evaluation of 99Tcm-DMSA SPET with three-dimensional reconstruction in 68 patients with varied renal pathology.

SummarySixty-eight patients (135 kidneys) with varied renal pathology were evaluated with 99Tcm-dimercapto-succinic acid (DMSA) single photon emission tomography (SPET) to determine whether it is possible to detect more renal abnormalities and to reduce the number of false-positives due to anatomical variants when compared with planar imaging. The patients ranged in age from 1 to 78 years and their pathologies included urinary tract infection (n = 50), space occupying lesions (n = 5), calculi (n = 4), hypertension (n = 4) and others (n = 5). Planar scans were performed 3 h after the injection of 80 MBq of 99Tcm-DMSA and a 64 x 20 s acquisition over 360° was used for SPET. High-resolution collimation was used for both. Slices were displayed as transaxial, coronal and sagittal and/or oblique sagittal in the plane of the kidney. Three-dimensional (3D) images were formed by volume rendering. Each kidney was divided into three regions and each region scored separately for the presence of an abnormality. Planar scans were reviewed aione and then in conjunction with SPET and 3D images. Planar imaging detected 95 abnormal regions compared with 103 using SPET. SPET reduced the number of equivocal regions in 8 (12%) patients. The diagnosis was altered by SPET in 17 (4%) regions in 14 (21%) patients. SPET and 3D 99Tcm-DMSA allow more abnormalities to be detected but also allow more specific definition of apparent abnormalities on planar imaging.