Reproducibility of lateral spine dual energy X-ray absorptiometry (LAT DEXA) scans using a Lunar DPX-L scanner was assessed in a cadaveric phantom and in patients. One hundred phantom measurements over 7 months demonstrated a longitudinal stability of 1.7% (coefficient of variation, CV). Additional scans were performed with the phantom rotated by up to 20 degrees in each of the three orthogonal planes to assess the effects of variable patient positioning. Horizontal and vertical rotation of the spine had little effect on the estimated bone mineral density (BMD), however, axial rotation of greater than 8 degrees led to errors in the BMD measurement. One hundred consecutive patients had two lateral scans performed within 1 month. BMD (range 0.10-1.6 g/cm2) was determined for each scan by one operator. Significant overlap from ribs and pelvis was often seen with L2 and L4 vertebrae but one vertebra (L3) could be measured in every case. Intraoperator and interoperator variability was assessed by three experienced operators, each analyzing 10 patients' scans on five separate occasions, and was found to be less than 1.1% for a single vertebra. BMD estimation of vertebral bodies and midslices by lateral DEXA scans (CV% of 3.8% and 4.6%) have a 95% confidence interval of 0.074 g/cm2 and 0.096 g/cm2, respectively for two vertebrae. This variability is due mainly to axial rotation, with operator variability, horizontal rotation, and vertical rotation having little effect on BMD estimation.

Indium-111 oxine labelled leucocyte (111In oxine leucocyte) scintigraphy is the test of choice in detecting occult infection and localising focal inflammation. 111In oxine labelling is technically difficult and expensive and leucocyte labelling with technetium-99m stannous colloid (99mTc Sn colloid) has been considered to be an alternative. Leucocytes from 40 cases referred for investigation of occult infection or localisation of inflammation were simultaneously labelled with 111In oxine and 99mTc Sn colloid with dual isotope acquisition performed at 1, 3 and 24 h. Twenty-four hour 99mTc Sn colloid scans were corrected for 111In downscatter. Each case was independently interpreted by two experienced observers. Twenty-one patients demonstrated positive 111In oxine leucocyte scans. Using 111In oxine leucocyte scans as the gold standard, 99mTc Sn colloid leucocyte scanning had an overall sensitivity of 86% and a specificity of 95%. Clinical follow-up verified that three patients had false negative 99mTc Sn colloid leucocyte scans and one patient had a false positive. Further clinical evaluation of 99mTc Sn colloid labelled leucocytes is required before they can become a reliable replacement for 111In oxine leucocytes.

Unilateral cryptorchidism was induced in Wistar rat pups within 48 h of birth. After a period of 150 days, the blood-testis barrier was evaluated in the cryptorchid and contralateral scrotal testis, using a lanthanum immersion technique. The barrier was demonstrated to be competent, with tracer confined to the basal and intermediate compartments.