Feasibility of Q.Clear Reconstruction Algorithm in Reducing Radiopharmaceutical Dose for Adrenal 68Ga-Pentixafor PET/MR Imaging

Objective To evaluate whether the Q.Clear reconstruction algorithm can maintain comparable image quality and diagnostic efficacy to Ordered Subset Expectation Maximization(OSEM) in 68Ga-Pentixafor imaging with reduced radiopharmaceutical dosage.Methods Thirty-five patients with primary aldosteronism who underwent 68Ga-Pentixafor PET/MR at West China Hospital,Sichuan University were retrospectively enrolled.Data were acquired for 6 minutes per bed position and subsequently partitioned to simulate shorter acquisition times(1.0,1.5,2.0,3.0,and 6.0 minutes/bed).Images were reconstructed using both Q.Clear(β=1000) and OSEM.Subjective assessments included image noise,lesion clarity,and overall image quality scores.Objective metrics encompassed signal-to-noise ratio(SNR),lesion-to-background ratio(L/B),standardized uptake values(SUVmax,SUVmean),and background noise(SD).Results Subjective assessments showed that Q.Clear achieved diagnostic-quality images (score ≥3) in acquisition time groups of 1.5 minutes or longer (n=28). The 3.0-minute group demonstrated optimal scores for image noise, lesion conspicuity, and overall quality. Objective analyses revealed superior noise suppression with Q.Clear across all time groups compared to OSEM (P<0.05). Notably, no significant differences were observed between Q.Clear at 1.5 minutes and OSEM at 6.0 minutes in SNR (51.5±26.0 vs 57.1±25.6,P>0.33) or L/B (11.2±5.23 vs 11.7±5.30,P>0.90).Conclusion Maintaining a 6-minute acquisition time per bed position with 25% injected dose and Q.Clear reconstruction (β=1000) provides sufficient image quality for clinical diagnosis.This finding supports the development of low-dose scanning protocols and contributes to radiation safety in precision diagnosis and treatment of adrenal tumors.