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This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Eberl, S. Articles by Fulham, M. PubMed Articles by Eberl, S. Articles by Fulham, M.

Comparison of 3 ring and 4 ring Biograph TruePoint PET/CT Systems

¹ PET and Nuclear Medicine, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia

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Objectives: To compare the performance and throughput of a Siemens TruePoint 4-ring (4R) PET/CT system with an axial field of view (AFOV) of 21.6 cm with the 3-ring (3R) system (AFOV=16.2cm).

Methods: The 3R scanner was used for 8 months clinically before it was upgraded to 4R. NEMA NU2-2001 performance tests were done on both 3R and 4R configurations. We identified 22 patients (14M, 8F) who had whole body FDG PET/CT scans on both configurations(mean±sd, range age: 58.5±12.9, 30-77yr, weight: 73±10.7, 45-94kg, height: 169±11.3, 149-188cm). Injected activity (3R 347±19.3MBq, 4R 361±20.1MBq) and time per bed were kept the same for the 3R and 4R studies. We compared the number of beds to cover the required patient area between the two configurations. Patient based noise equivalent count rates (NEC) over the abdomen were estimated using the method of Watson et al (J Nucl Med 46:1825-1834) with vendor-supplied software.

Results: The NEMA NU2-2001 sensitivity improved from 4.6cps/kBq (3R) to 8.1cps/kBq (4R) and the peak NEC from 95kcps to 162kcps. NEC at 10kBq/cc increased from 61kcps to 109kcps. Resolution and scatter fraction were the same for the two configurations. Average number of beds was 5.88±0.5 for 4R and 7.88±1.6 for 3R; this was a reduction by a factor of 1.34 for the 4R system, which is consistent with the factor of 1.33 predicted by the relative AFOV. Patient based NEC estimates were 1.76±0.31 times higher for 4R compared to 3R; the gain in patient NEC is consistent with the gain in NEMA sensitivity (1.76) and peak NEC (1.71) as well as NEC at 10 kBq/cc (1.79).

Conclusions: An increase in the AFOV from 16.2 cm to 21.6 cm improved sensitivity and NEMA and patient NEC by about 75%, without deterioration in resolution and scatter fraction. The increased AFOV can thus increase patient throughput and improve image quality.

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Eberl, S. Articles by Fulham, M. PubMed Articles by Eberl, S. Articles by Fulham, M.