• Tatsuo Torizuka, Yasuo Tanizaki, Toshihiko Kanno, Masami Futatsubashi, Etsuji Yoshikawa, Hiroyuki Okada, and Yasuomi Ouchi.
• Research Center for Child Mental Development, Hamamatsu University School of Medicine, Hamamatsu, Japan. tatsuo@hama-med.ac.jp
• J. Nucl. Med. 2009 Oct 1; 50 (10): 1579-84.

UnlabelledThis study was designed to compare tumor (18)F-FDG uptake between a single 20-s acquisition of deep-inspiration breath-hold PET/CT and free-breathing PET/CT for lung cancer.MethodsBefore the clinical study, a phantom study was performed to determine the optimum breath-hold time for the PET scan. We studied 47 patients with lung cancer who underwent free-breathing PET/CT with the standard clinical protocol, followed by deep-inspiration breath-hold PET/CT of the thorax. In breath-hold PET/CT, the patients were asked to hold their breath in deep inspiration for 10 s during the CT scan and for 20 s during the PET scan. Maximum tumor (18)F-FDG standardized uptake value (SUVmax) was measured in free-breathing PET and breath-hold PET, and the percentage difference between these 2 values was calculated.ResultsBreath-hold PET showed a significant increase in SUVmax, as compared with free-breathing PET (8.26 +/- 4.59 vs. 11.25 +/- 7.24, P < 0.0001). The mean difference in SUVmax was 39.5% +/- 43.4%, and the range was 2.9%-248.3%. The difference in SUVmax was significant when compared between tumors in the upper lung (n = 22) and tumors in the lower lung (n = 25) (24.4% +/- 17.7% vs. 52.9% +/- 54.3%, P = 0.0077). The mean tumor size of the group with a high SUVmax difference (n = 13) was significantly smaller than that of the group with a low SUVmax difference (n = 34) (2.45 +/- 0.87 cm vs. 3.21 +/- 1.22 cm, P = 0.043), using a cutoff of 39.5%.ConclusionThe single 20-s acquisition of breath-hold PET/CT enabled more precise measurement of SUVmax, especially in the lower lung field and for small tumors, which may be affected by respiratory motion. This technique is feasible in the clinical setting and requires only a minor increase in examination time.

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