@misc{oai:repo.qst.go.jp:00071320,
 author = {Tanimoto, Katsuyuki and Yoshikawa, Kyosan and Shiraishi, Takahiro and Ishii, Noriyuki and Toubaru, Sachiko and Ohashi, Seiya and Saga, Tsuneo and Tajiri, Minoru and Kato, Atsushi and Miyazaki, Masaru and Shibayama, Kouichi and Tsuji, Hiroshi and Ando, Yutaka and Kamada, Tadashi and 谷本 克之 and 吉川 京燦 and 白石 貴博 and 石井 徳幸 and 桃原 幸子 and 大橋 靖也 and 佐賀 恒夫 and 田尻 稔 and 宮崎 勝 and 柴山 晃一 and 辻 比呂志 and 安藤 裕 and 鎌田 正},
 month = {Oct},
 note = {Objective
Various parameters are used for measuring tumor glucose metabolic activity with 18F-FDG PET including measuring the single maximum pixel value within the slice with highest radioactivity concentration (SUVmax) or placing a fixed ROI in the area of the tumor with the highest level of 18F-FDG uptake (SUVpeak), which it defines as the largest possible mean value of a spherical VOI with radius 10 mm positioned within a tumor (SUVpeak10). It is said that the amount of tumor stroma correlates with prognosis of patients with cancer. We estimated the amount of tumor stroma with 18F-FDG-PET using SUVmax and SUVpeak10, and evaluated the prediction performance of the amount of tumor stroma with 18F-FDG-PET after surgery of pancreatic cancer.
Methods
Sixteen pre-surgery patients with either proven or suspected primary pancreatic cancer underwent 18F-FDG-PET/CT. The pathologically confirmation found out 13 malignancy in all cases. 
According to pathological findings, the stroma of tumors were quantitatively classified in 3 types (Scirrhous type: abundant stroma, Intermediate type: a type intermediate between the scirrhous type and the medullary type, and Medullary type: scanty stroma). We evaluated the correlation between the amount of tumor stroma and each 3 indexes, SUVmax, SUVpeak10 and SUVstroma. SUVstroma was calculated by the following equation:
SUVstroma =1- [SUVpeak10] / [SUVmax]
18F-FDG accumulates in tumor cells but does not accumulate so much in stromal cells. The tumor with abundant stroma might be low SUVpeak10, so SUVstroma might be high. Because the tumor cell avidly accumulates 18F-FDG but stroma does not so much.
Each 3 indexes of SUV (SUVmax, SUVpeak10 and SUVstroma) were statistically compared with 3 types of stroma classification using the Mann-Whitney's U test. The overall survival (OS) was calculated using Kaplan-Meier method by SUVs found statistically-significant with Mann-Whitney's U test.
Results
There was no patient with Medullary type in our cases. Statistically-significant difference was observed between Scirrhous type and Intermediate type in SUVstroma (p<0.05). No statistically-significant difference was observed between Scirrhous type and Intermediate type (p<1.0, p<0.53) in SUVmax and SUVpeak10.
Scirrhous type has a higher SUVstroma than Intermediate type. The patients with SUVstroma>0.3 had markedly lower OS rate than those with SUVstroma<0.3 (0% vs. 50% p<0.05). 
Conclusion
We think that SUVstroma could estimate the amount of tumor stroma, and it is useful for predicting prognosis of the patients with pancreatic cancer., EANM'13 - Annual Congress of the European Association of Nuclear Medicine},
 title = {A new approach to estimate the amount of tumor stroma as a prognostic factor using SUVmax and SUVpeak in pancreatic cancer},
 year = {2013}
}