Significant dose reduction employing dual-low-dose PET/CT in pediatric lymphoma: maintaining diagnostic, staging, and response-assessing efficacy.

[OBJECTIVES] To evaluate the clinical efficacy of a dual-low-dose total-body PET/CT protocol in pediatric lymphoma patients, incorporating low-dose PET imaging in combination with two distinct low-dose CT acquisition strategies.

[MATERIALS AND METHODS] Pediatric lymphoma patients (≤ 18 years) receiving half-dose [F]FDG (1.85 ± 0.2 MBq/kg) were prospectively enrolled and divided into low-dose CT group (LDCT) and ultra-low-dose CT group (ULDCT) using uEXPLORER scanner. Image quality was evaluated based on subjective and objective metrics. The reference standard of lesions was confirmed with pathological and follow-up evidence. The effective dose (ED), the diagnostic efficacy for detecting lesions, and the accuracy for staging, treatment responses were compared. Institutional Review Board approval was obtained.

[RESULTS] A total of 246 pediatric patients were enrolled (9.2 ± 3.8 years, 180 male). The LDCT (n = 127) and ULDCT (n = 119) had similar clinical characteristics (p > 0.05) except for male percentage (78.7% vs. 67.2%, p = 0.042). The total ED of ULDCT was significantly lower than that of LDCT (5.6 ± 1.9 mSv vs. 9.7 ± 3.2 mSv, p < 0.001). Both groups showed acceptable subject image quality and were comparable in main objective parameters. ULDCT showed a sensitivity lower than LDCT (99.0% vs. 99.9%, p = 0.010) in diagnosing lymph node lesions, while their specificity (96.0% vs. 94.3%) and area under curve (AUC, 0.978 vs. 0.982) were similar (both p > 0.05). LDCT and ULDCT were also comparable in diagnosing extranodal involvements (AUCs > 0.800), staging accuracy (94.6% and 93.6%), and response assessment accuracy (97.6% and 96.3%).

[CONCLUSIONS] Dual-low-dose total-body PET/CT allowed a significant reduction in total ED without compromising imaging quality and diagnosis performance in pediatric lymphoma patients.

[KEY POINTS] Question [F]FDG PET/CT scans are crucial for pediatric lymphoma patients; however, an optimized low-dose strategy has not been achieved. Findings Dual-low-dose PET/CT demonstrated sufficient image quality and clinical efficacy in pediatric lymphoma patients, with significantly reduced radiation exposure. The total radiation dosage of the ultra-low-dose CT protocol was 5.6 ± 1.9 mSv. Clinical relevance A dual-low-dose PET/CT protocol is an optimized imaging strategy for pediatric lymphoma patients that significantly reduces radiation exposure while providing sufficient clinical efficacy for diagnosing, staging and treatment response evaluation.