Reduction of the fluorine-18-labeled fluorodeoxyglucose dose for clinically dedicated breast positron emission tomography

Abstract

PurposeTo determine the clinically acceptable level of reduction in the injected fluorine-18 (18F)-labeled fluorodeoxyglucose (18F-FDG) dose in dedicated breast positron emission tomography (dbPET).MethodsA breast phantom with four spheres exhibiting various diameters (5, 7.5, 10, and 16 mm), a background 18F-FDG radioactivity of 2.28 kBq/mL, and a sphere-to-background radioactivity ratio of 8:1 was used. True dose-reduced dbPET images were obtained by data acquisition for 20 min in list mode at multiple time points over 7 h of radioactive decay. Simulated dose-reduced images were generated by reconstruction with a portion of the list mode acquisition data. True and simulated dose-reduced images were visually and quantitatively compared. On the basis of the phantom study, dbPET images for 32 breasts of 28 women with abnormal uptake were generated after simulated reduction of the injected 18F-FDG doses; these images were compared with those acquired using current clinical doses.ResultsThere were no qualitative differences between true and simulated dose-reduced phantom images. The phantom study revealed that the minimal required dose was 12.5% for the detection of 5-mm spheres and 25% for precise semi-quantification of FDG in the spheres. The 7-min reconstruction with a 100% dose was defined as the reference for the clinical study. The image quality and lesion conspicuity were clinically acceptable for the 25% dose images. Lesion detectability on the 12.5% dose images was maintained despite image quality degradation.ConclusionsIn summary, 25% of the standard 18F-FDG dose for dbPET can provide a clinically acceptable image quality, while 12.5% of the standard dose results in acceptable quality in terms of lesion detection when lesions are located at a sufficient distance from the edge of the dbPET detector.

Image quality evaluation of real low-dose breast PET

“…It was reported that PET image quality could be maintained even with reduced injection dose using simulated low-dose PET images reconstructed from divided list-mode data [ 8 ]. Furthermore, it has been reported that artificial intelligence technology could theoretically make the image quality of low-dose PET images equivalent to that of normal-dose images [ 21 ]; however, it has not yet been put to practical use in clinical practice.…”

“…Dose reduction related to the use of dbPET based on phantom tests and clinical cases was previously evaluated; the results revealed that by employing 25% of the standard 18 F-FDG dose, it is possible to obtain a clinically acceptable image quality, and 12.5% of the standard dose results in an image quality that is still sufficient for the detection of lesions [ 8 ]. In the aforementioned study, low-dose images were simulated for clinical cases.…”