Ultrafast bone scintigraphy scan for detecting bone metastasis using a CZT whole-body gamma camera.

Purpose: To evaluate the feasibility of short whole-body bone scan acquisition times using a novel gamma camera with cadmium-zinc-telluride (CZT) semiconductor detectors.

Methods: We retrospectively enrolled 78 consecutive patients with prostate cancer who underwent bone scintigraphy using a whole-body gamma camera with CZT detectors. After acquisition of list-mode data with 180 s per bed position, anterior and posterior whole-body images were reconstructed using the first 5%, 10%, 25%, 50%, 75% and 100% of the list-mode data. Two experienced nuclear medicine physicians interpreted the images, and interrater agreement and the diagnostic value of the images were determined. Quantitative artificial neural network (ANN) values, bone scan indexes (BSI) and hotspot numbers (HsN) were also calculated by automated diagnostic software.

Results: Excellent interrater reliabilities of the visual assessments were obtained for the 100%, 75%, 50%, and 25% images (κ = 0.88, 0.88, 0.88 and 0.88, respectively). The 5% images also showed high diagnostic value (sensitivity 0.94, specificity 0.84 and accuracy 0.86). Intraclass correlation coefficients (ICC) between the 100% images and the reduced acquisition time images were evaluated in quantitative analyses, and excellent correlations were observed for ANN value in the 75% images (ICC 0.77), for BSI in all the reduced acquisition time images (75%, 50%, 25%, 10% and 5%; ICC 0.99, 0.99, 0.99, 0.96 and 0.75, respectively), and for HsN in the 75%, 50%, 25% and 10% images (ICC 0.99, 0.99, 0.98 and 0.90, respectively).

Conclusion: Whole-body gamma cameras with CZT detectors have the potential to reduce image acquisition times and the dose of radioisotope injected for bone scans.