Parathyroid imaging: the importance of pinhole collimation with both single- and dual-tracer acquisition.

UNLABELLED: Our objective was to rigorously compare pinhole and parallel-hole collimation in an intrapatient, intrastudy design in 2 parathyroid imaging protocols: the first was dual-phase (99m)Tc-sestamibi imaging, and the second was dual-phase (99m)Tc-sestamibi plus dual-tracer ((99m)Tc-sestamibi and (123)I) simultaneous-acquisition subtraction imaging. METHODS: Thirty-three patients with 37 surgically proven nonectopic parathyroid adenomas were evaluated. Anterior pinhole and parallel-hole images of the neck were available for (99m)Tc-sestamibi at 15 min and 3 h, and for simultaneously acquired (99m)Tc-sestamibi and (123)I subtraction at 15 min, all from a single study. The images were modified so that all had a square border and so that the thyroid filled approximately three quarters of the image. The images were evaluated by 2 experienced nuclear medicine physicians who did not know the surgical results or whether the images were acquired with pinhole or parallel-hole collimation. The observers indicated the location of any identified adenoma and graded the certainty of diagnosis on a 3-point scale. RESULTS: The localization success rate for the 2 observers combined for the single-tracer dual-phase images was 66.2% with pinhole collimation and 43.2% with parallel-hole collimation (P < 0.0001). The localization success rate with the addition of the dual-tracer simultaneous-acquisition subtraction image was 83.8% with pinhole collimation and 62.2% with parallel-hole collimation (P = 0.0018). In addition, the degree of certainty of localization was greater with pinhole collimation with both imaging protocols (P < 0.001 in both cases). CONCLUSION: In the anterior projection, pinhole collimation is superior to parallel-hole collimation for parathyroid imaging with either dual-phase (99m)Tc-sestamibi or dual-phase (99m)Tc-sestamibi plus dual-tracer ((99m)Tc-sestamibi and (123)I) simultaneous-acquisition subtraction.

Determination of split renal function by 3D reconstruction of CT angiograms: a comparison with gamma camera renography.

OBJECTIVE: The objective of our study was to examine the correlation between CT-based and radionuclide renography-based measures of split renal function in a healthy population of live potential kidney donors using 3D models generated from CT angiography. MATERIALS AND METHODS: The records of 173 renal donor candidates who had undergone CT and radionuclide renography between March 1, 2005, and February 28, 2006, were retrospectively evaluated; of those 173 patients, 152 met study inclusion criteria. A blinded investigator using 3D models that were created semiautomatically from the unenhanced, arterial, and excretory phase data made measurements of CT renal volumes and attenuations. The mean renal attenuation and volume were used to calculate the net accumulation of contrast material and split renal function for comparison with radionuclide renography. Split function from CT was calculated in the arterial and excretory phases as well as based on split renal volume and the Patlak method. RESULTS: All four CT-based methods for the calculation of split renal function showed correlation with no significant difference from radionuclide renography (p > 0.05, Student's t test). Pearson's correlation coefficients varied from 0.36 to 0.63 (p < 0.001 for each). Difference scores revealed that the excretory and renal volume splits had the narrowest range and showed a linear, nonzero relationship to the renography splits. Bland-Altman analysis confirmed that the majority of difference scores between each CT method and the radionuclide renography were within the 95% CI of the differences. CONCLUSION: Split renal function based on 3D CT models can provide a "one-stop" evaluation of both the anatomic and the functional characteristics of the kidneys of living potential kidney donors. The excretory phase data and the split renal volume data show the best correlation and the smallest difference scores compared with radionuclide renography data.

The Stamp-in-Safety program: a behavioral intervention to reduce behaviors that can lead to unintentional playground injury in a preschool setting.

OBJECTIVE: To introduce and evaluate the Stamp-in-Safety program, a behavioral intervention designed to increase the quality of supervision by teachers on preschool playgrounds and to reduce the risk of unintentional child playground injury. METHODS: A quasi-experimental time series design was used, with observational techniques, to evaluate behavior on the playground before, during, and after the intervention as well as during a 6-month post-intervention assessment. RESULTS: Both applied behavior analysis techniques and inferential statistics suggest that the Stamp-in-Safety program resulted in behavioral changes likely to reduce the risk of child injury on the playgrounds of childcare centers. CONCLUSION: Results indicate promise for the Stamp-in-Safety program as a low-cost, easily implemented intervention to reduce pediatric playground injury risk at childcare centers. Suggestions for future research are offered.