We were able to clarify the performance profile of "FDG-PET for cancer screening" on the basis of a Japanese nationwide survey. The number of facilities possessing PET is increasing steadily, highlighting the necessity of evaluating the usefulness of "FDG-PET cancer screening" as soon as possible by undertaking long-term investigations of large series of subjects.

ObjectiveThe aim of this study was to survey the 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program conducted in Japan.MethodsThe “FDG-PET cancer screening program” included both FDG-PET and positron emission tomography with computed tomography (PET/CT) with or without other combined screening tests that were performed for cancer screening in asymptomatic subjects. A total of 155,456 subjects who underwent the FDG-PET cancer screening program during 2006–2009 were analyzed.ResultsOf the 155,456 subjects, positive findings suggesting possible cancer were noted in 16,955 (10.9 %). The number of cases with detected cancer was 1,912 (1.23 % of the total screened cases, annual range 1.14–1.30 %). Of the 1,912 cases of detected cancer, positive findings on FDG-PET were present in 1,491 cases (0.96 % of the total number of screened cases). According to the results of further examinations, the true positive rate for subjects with suggested possible cancer (positive predictive value) was 32.3 % with FDG-PET. Cancers of the colon/rectum, thyroid, lung, and breast were most frequently found (396, 353, 319, and 163 cases, respectively) with high PET sensitivity (85.9, 90.7, 86.8, 84.0 %, respectively). Prostate cancer and gastric cancer (165 and 124 cases, respectively) had low PET sensitivity (37.0 and 37.9 %, respectively). The Union for International Cancer Control (UICC) clinical stage of cancer found with the FDG-PET cancer screening program was mainly Stage I.ConclusionsThe FDG-PET screening program in Japan has detected a variety of cancers at an early stage. However, several cancers were found in repeated FDG-PET cancer screening program, indicating the limitation of a one-time FDG-PET cancer screening program. The value of the FDG-PET cancer screening program is left to the judgment of individuals with regard to its potentials and limitations.

We propose a new algorithm named "Qiroit,filter (QPlter~ " to e.vtruct the isolated but low amplitude shudow located in the background which h a y extremely high amplitdeJuctuution. @filter is a kind of mathematical morphology and its formulation is quite simple. This simplicity brings about a unique merit that output from this filter is analytically eqmssivefior the case of analyical input shupes like ball, cone, or rotation of cosine function, which have churucteristics of rotation qwimetry a d monotonic decreasing from the origin.This Q-filter is composed of two sequential operation named Q Trans. and Q Inv. Trans. , each operation having an interesting characteristics as follows : Q Trans. corresponds to e-rtract feature Imrameter like a matched filter from input image having non ideal isolated shudow, and Q Inv. Trans. correspond.Y to restore isolated image using extracted feature paranieter. This filter is applied to detect the cancer candidate shadow automatically in the CT cross sections of lung areas. aiming to reduce drastically the number of cross sections to be diagnosed by the doctor.

in this paper, we report the image processing technique for computer-aided diagnosis of lung cancer screening system by CT (LSCT). LSCT is the newly developed mobile-type CT scanner for the mass screening of lung cancer by our project team. in this new LSCT system, one essential problem is the increase of image information to be diagnosed by a doctor to about 30 slices per patient from I X-ray film. To solve this difficult problem, we are trying to reduce the image information drastically to be displayed for the doctor by image processing techniques. We propose a new method named Variable New-Quoit filter for the automatic recognition of the pathological shadow candidates. Our computer aided diagnosis (CAD) system can satisfactoiily reduce the number of CT cross sections by this method, containing the abnormal shadow candidates.

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