RT Journal Article
SR Electronic
T1 Unchanged quality despite reduced doses in planar and SPECT bone scintigraphy.
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1524
OP 1524
VO 61
IS supplement 1
A1 Justin Peacock
A1 Ilsup Yoon
A1 Kevin Banks
YR 2020
UL http://jnm.snmjournals.org/content/61/supplement_1/1524.abstract
AB 1524Objectives: As Nuclear Medicine (NM) technology improves the capability for performing adequate NM studies with reduced radiopharmaceutical doses increases. The SNMMI guidelines suggest that bone scintigraphy (BS) can be performed at doses of 99mTc-MDP from 13-30 mCi and a recent study surveying NM facilities across the US demonstrated an average dose of 24.6 mCi (standard deviation 3.5 mCi) [1,2]. There are limited studies demonstrating the quality of BS at different doses, and what minimum doses can adequately be used in BS [1-4]. Over the past 6 years, we have reduced the dose for BS from 25 to 20 to 15 mCi. Subjectively, we have not noticed significant differences in BS quality with each reduction. We decided to study this rigorously using established quality metrics. Methods: We anonymized 50 random whole body planar and 25 random SPECT images for each of the doses, namely 25 mCi, 20 mCi, and 15 mCi. These were then shown to two NM staff, one NM fellow, two senior radiology residents, two junior residents, and two NM technologists. They were asked to score the images, using visual quality standards similar to Gustafsson et al [3]. They were also asked to estimate the BS dose used for each study. Visual grading ordinal regression analysis was performed on the results to determine significant quality differences among the doses [5]. Results: Comparing the quality standard scores for the whole body planar images, we did not observe a significant difference in quality among the different doses. The quality standard scores for SPECT imaging did not demonstrate a significant difference for the different doses. The reviewers were not able to accurately identify the doses used for different studies. Quality scores among the different categories of reviewers were not significantly different from each other. Conclusions: Reducing the BS dose from 25 to 20 to 15 mCi did not result in significantly different quality standard scores among a wide-range of reviewers, including physicians, trainees, and NM technologists. At BS doses of 20 mCi, the estimated whole body effective dose is 4 mSv, so at 15 mCi, the effective dose is likely very close to background radiation (3 mSv) [6]. Further studies at other institutions are needed to confirm equivalent quality at lower doses with different scanners, but we feel that BS doses can be safely lowered without sacrificing quality.