Background: Positron Emission Mammography (PEM) is a new modality in the investigation of breast cancer in Rajavithi
Hospital, and its effectiveness has not yet been evaluated.
Objective: To study the effectiveness and characterization of breast images taken with PEM in Rajavithi Hospital.
Material and Method: This was a retrospective study in which data were collected and analyzed of patients who were
investigated by PEM in Rajavithi Hospital between 18 September 2013 and 31 May 2014. Lesion to background (LTB) ratio of >2.0 with focal localization was considered to be suggestive of PEM positive for malignancy.
Results: Twenty-three female patients were included in the study, and their mean age was 51.7 years. Mean fasting blood
glucose (FBS) was 93.64 mg/dl, and mean Fluorodeoxyglucose (FDG) injected dose was 7.76 mCi. The average PUV mean
of background of both breasts decreased with advancing age. Fourteen patients were pathologically diagnosed with a total of
lesions, of which 12 were malignant and four were benign. The positive predictive value (PPV) was 76.92%, and the mean LTB of true positive lesions was 5.31. Three false positive lesions were found: one mild atypical cell, one papilloma and one
fibroadenoma, and the mean LTB was 2.92. The two false negative lesions were both DCIS.
Conclusion: There was a moderate PPV in this PEM study for breast cancer in Rajavithi Hospital, and investigators need
further experience and training in interpreting PEM. The information of mammographic, ultrasonographic and clinical
findings should be used together with PEM to make diagnostic decision. The addition of biopsies could also improve the efficacy of PEM studies.

Keywords: Positron emission mammography, PEM, Breast cancer, Breast imaging, F18-FDG