Half of the participating centres could potentially make use of resolution recovery to reduce the administered activity for myocardial perfusion scans without changing their routine acquisition protocols. The other half could consider adjusting the reconstruction parameters used with their resolution recovery software if they wish to use reduced activity successfully.
Gamma-camera uniformity is often monitored for quality control of performance. Many parameters can be derived from computer analysis of the image of a uniform (flood) source to obtain quantitative measures of uniformity. However, it is not clear which best reflect changes in uniformity, or how action levels should be set. The latter are essential for an automated analysis. To compare the various parameters and assess two techniques used for their analysis, a series of technetium-99m flood images were obtained consecutively. After establishing a baseline from repeated images, uniformity was degraded by offsetting the pulse height analyser (PHA) window by a small amount. Nine non-uniformity parameters were calculated for each flood image, including the Department of Health and Social Security (DHSS) and National Electrical Manufacturers Association (NEMA) integral and differential uniformities, the uniformity index and the percentage of pixels more than 5% from the mean. All parameters were calculated for both central field-of-view (CFOV) and useful field-of-view (UFOV). Eighty such trials were carried out on two gamma-cameras. The PHA offsets ranged from 1-10 keV. The two techniques used for analysis were the control chart and cusum analysis. Decision levels were set for each parameter, as multiples of SD for the control charts or by varying the dimensions of a truncated V-mask for cusum analysis. Receiver operating characteristic (ROC) curves were then used for an objective comparison of the parameters and of the analysis techniques. The area under the ROC curve was used to rank the parameters in order of sensitivity to change in uniformity.(ABSTRACT TRUNCATED AT 250 WORDS)
The audit concluded that the practical implementation of filtering, such as the size of the kernel, has a profound effect on the results, producing large differences between systems. Nevertheless, this work shows how users can quantify the frequency response of their own systems so that it will be possible to compare two systems in order to find filter parameters on each that produce equivalent results. These findings will also make it easier for users to replicate filters similar to other published results, even if they are using a different computer system.
Calculation of functional parameters from GMPI using technetium-99m-labelled radiopharmaceuticals is reliable and shows limited variability across the UK.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.