Dear Editor,

We thank the author’s interest in our report entitled ‘breast cancer screening by fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission mammography (PEM)’ [1].

Although, the commercial use of molecular breast imaging (MBI) is not available currently in our country, it has widely been adopted for breast cancer screening in other countries [2]. Supplemental use of MBI in mammographically dense breasts at reduced radiation dose was reported to yield the cancer detection rate [3]. As the author pointed out, we agree that MBI may be favorable if considering radiation exposure to breast and cost per examination. However, to clarify the true difference of imaging sensitivity, because the 2 % difference is too small, direct comparative study between MBI and PEM is needed. We believe that the advantage of PEM is its higher spatial resolution, provided by 12 images per 1 scan, and the semiquantative analysis. Both MBI and PEM have shown variable levels of background uptakes, which can lead misinterpretations. The semiquantative analysis of PEM is useful to differentiate benign from malignant lesions in such cases [3]. Another advantage of PEM is that PET(/CT) scans can be taken without adding another FDG. Opportunistic cancer screening using FDG-PET is widely spread in our country. The cancer detection rate is reported 1.14 % [4]. We hope that further studies are needed to clarify the adequate use of MBI and PEM.