Diagnostic accuracy of SPECT/CT for parathyroid adenoma: Tracer selection and quality control

Accurate preoperative detection and localization of parathyroid adenomas is essential for successful minimally invasive parathyroid surgery. Although technetium Tc 99 m sestamibi (MIBI) and technetium Tc 99 m tetrofosmin (Myoview) are both used for parathyroid scintigraphy, differences in diagnostic performance, particularly in the context of quality control (QC) variability, remain insufficiently defined. This study evaluated the impact of radiopharmaceutical choice and QC adherence on the accuracy of dual-phase planar imaging and SPECT/CT for parathyroid adenoma detection and localization.

This retrospective observational diagnostic accuracy study included 60 adults (aged 47-67 years) with suspected primary hyperparathyroidism who underwent dual-phase planar scintigraphy and SPECT/CT at a tertiary nuclear medicine center and subsequently had surgical and histopathologic confirmation. Patients were divided into four equal groups (n = 15 each) based on radiopharmaceutical (MIBI vs. Myoview) and QC adherence (regular vs. irregular). Imaging outcomes were classified as true-positive, false-negative, or localization error using surgery as the reference standard. Group differences were analyzed using χ² or Fisher's exact tests (two-tailed α=0.05). Administered radiopharmaceutical activities and CT-based radiation-dose metrics (CTDIvol, DLP, effective dose) were summarized descriptively.

SPECT/CT detected 51 of 60 adenomas (85.0%) and correctly localized 44 of 60 (73.3%), substantially outperforming planar imaging (23/60, 38.3%). QC adherence significantly influenced diagnostic performance: detection was 100% (30/30) with regular QC and 70.0% (21/30) with irregular QC (p = 0.001). Under irregular QC conditions, Myoview produced more false-negative results and localization errors compared with MIBI, especially for ectopic lesions. Administered activities (675-770 MBq) and CT radiation-dose parameters were within expected clinical ranges but showed greater variability in the irregular QC groups.

SPECT/CT provides superior detection and localization of parathyroid adenomas compared with planar scintigraphy. Consistent QC is critical for optimal diagnostic performance, and MIBI demonstrates greater robustness than Myoview when QC procedures are not reliably maintained.

Parathyroid adenomas are small glands that can cause illness when they become overactive. This study tested how imaging drugs and good equipment checks affect how well scans find and locate these glands. This study found that SPECT/CT did better than standard imaging and that strong quality control improved accuracy. This matters because clear and reliable imaging helps people get precise surgery with fewer risks.