Multicenter evaluation of renography with an automated physical phantom.

PURPOSE: The diversity of the dynamic radionuclide renal imaging (renography) study protocols sets challenges for the overall study quality, therefore raising a need for national quality control. The aim of this study was to encourage the standardization of renography in Finland and to evaluate the development after a previous study performed in 1997. METHODS: The new Heikkinen phantom was imaged in each of the 20 participating nuclear medicine laboratories. The results were interpreted in the manner of a regular patient study, and reconstructions and printouts were made according to the clinical routines of each laboratory. Four quantitative parameters were calculated and compared between laboratories. The reports were also assessed in a blind test. RESULTS: The average error in T(max) values ranged from -5 to 7% (-29 to +18% in 1997), in T(1/2) from 0 to 35% (-43 to +66%), in RCA20 from -20 to +28% (-50 to +82%) and in relative uptake from -3 to 5%. The difference from average in relative uptake ranged from -4 to 5% (-21 to +36%). CONCLUSION: The results showed that the errors in T(max) and relative uptake were generally within quite acceptable margins, and the variation in quantitative parameters between laboratories was shown to be smaller than 14 years earlier. The reason might be the use of new software packages as well as increased efforts to improve the quality of the studies.

Interdepartmental audit with an anatomically realistic lung phantom.

UNLABELLED: The diagnostic proficiency of nuclear medicine professionals and the accuracy of equipment may be tested with phantoms. All phases of the imaging chain should be included in the external quality assurance of imaging. METHODS: The aim of this study was to evaluate and compare the quality of nuclear imaging of the lung in Finland. For this purpose, we developed a new anatomically realistic lung phantom. The phantom consisted of plastic containers filled with plastic pellets to imitate the 3-dimensional shape of the lungs. These containers were filled with radioactive liquid and placed inside an anatomically accurate phantom of the chest cavity. The attenuation properties of the phantom were close to those of a real human thorax. Perfusion and ventilation defects were positioned inside the phantom to mimic 2 clinical cases. The phantom was imaged and interpreted as a patient simulation study in 18 Finnish hospitals. Reconstruction, printout, and reporting were according to the clinical routine of each hospital. The quality of the image sets and reports was evaluated and scored from 0 to 10. Additionally, technical performance was evaluated by a nuclear medicine specialist and hospital physicians. RESULTS: The average score (+/-SD) for overall quality was 7.1+/-1.1 (range, 5.2-8.5). Reports received a score of 7.2+/-1.7 (4.7-10.0); image sets, 7.2+/-1.3 (4.8-9.7), technical evaluation by hospital readers, 6.5+/-2.3 (1.6-9.5); and technical evaluation by a specialist, 7.8+/-1.2 (5.7-10.0). CONCLUSION: Lung imaging routines and the results of this survey were diverse. None of the participating hospitals routinely used tomography. In planar imaging, the most valuable projections were oblique (left anterior oblique, right anterior oblique, left posterior oblique, and right posterior oblique) and straight sides (right and left). The phantom mimics variable clinical situations well and is suitable for testing of imaging protocols and for proficiency testing of nuclear medicine professionals and equipment. Clinical phantom studies are an effective way of assessing an imaging program.