Recent Advances in SPECT Myocardial Perfusion Tracers: Tc-99m-4BOH.

PURPOSE OF REVIEW: This review traces the rationale behind the development of the novel myocardial perfusion tracer 99mTc-4BOH, summarizes the current evidence from preclinical and first‑in‑human studies, and discusses the challenges ahead for clinical translation. RECENT FINDINGS: Preclinical and first-in-human studies demonstrated that 99mTc-4BOH possessed a significantly higher myocardial uptake rate (K1) compared to 99mTc-Sestamibi and superior retention stability compared to 99mTc-teboroxime. 99mTc-4BOH also exhibited improved liver kinetics, with the highest heart-to-liver ratios during the early phase after injection. The 1T model was optimal for dynamic 99mTc-4BOH SPECT and 4-min acquired data was sufficient for reliable global and regional K1 quantification. 99mTc-4BOH exhibits a favorable pharmacokinetic profile and offers the potential for high-precision SPECT MBF quantification with improved clinical throughput. Formal regulatory trials and broader camera validation remain the key next steps. If successful, it could bring routine MBF quantification to thousands of SPECT laboratories worldwide.