Evaluation of different counting methods for use in radiochemical purity testing procedures for 99mTc-labelled radiopharmaceuticals.

The efficiency and accuracy of different methods for quality control of radiopharmaceutical preparations for diagnostic purpose were studied. The radiochemical purity of (99m)Tc Tetrafosmin, (99m)Tc Exametazime, (99m)Tc Sestamibi and (99m)Tc Oxidronate was evaluated by different thin layer chromatography systems, followed by cutting of the strips into two or three sections and by the measurement of radioactivity distribution by dose calibrator or gamma counter. In addition, to confirm the accuracy of these routine procedures, the strips were cut into a number of micro-sections (14-25) and each of them evaluated by the gamma counter.

Geometry and bone mass in primary hyperparathyroidism assessed by peripheral Quantitative Computed Tomography (pQCT).

Purpose: Non-invasive measurement by peripheral quantitative computed tomography (pQCT) of bone geometry, biomechanics, and mineral content in patients (pts) with primary hyperparathyroidism (PHPT).

Materials And Methods: Total, trabecular and cortical mineral density (totBMD, cortBMD, trab BMD), bone geometrical properties (total area, trabecular area, cortical area, cortical/total area) and cortical thickness as biomechanical parameters, were assessed by pQCT at distal radius in 38 (32 F; 6 M) consecutive patients with PHPT (mean age: 62 yrs; range: 30-77). In a subgroup of 12 patients, bone mineral density (BMD) was also measured by means of dual X-ray absorptiometry (DXA) at the lumbar spine (L2-L4).

Severe cortical and trabecular osteopenia in secondary hyperparathyroidism.

Background: Peripheral quantitative computed tomography (pQCT) provides real volumetric bone density values, not only of the total, but also of trabecular and cortical bone, separately. In addition, it provides data on bone geometry that can be related to the risk of fracture.

Methods: Total, cortical, and trabecular volumetric bone mineral densities (BMD), as well as the main geometric parameters (cross-sectional area, cortical area, trabecular area, and cortical thickness) were assessed by pQCT at the distal radius in 24 hemodialysis patients affected by severe secondary hyperparathyroidism (PTH, mean +/- SD: 1444 +/- 695 pg/mL).