الفهرس | Only 14 pages are availabe for public view |
Abstract east cancer remains the most prevalent cancer in women of developed countries with great social and economic impact. The scientific community is therefore focused on improving imaging methods for screening and staging of breast cancer. Conventional screening has traditionally included a combination of breast self-examination, clinical breast examination, and screening mammography. Although current imaging modalities such as mammography, ultrasonography, and magnetic resonance imaging focus on an anatomic approach, they do not provide sufficient data about the pathophysiology of malignant breast lesions. Positron emission mammography (PEM) is an innovative technology specifically designed to visualize the physiologic and metabolic processes in malignant breast lesions and can be performed on patients unable to have an MRI scan. The technology of PEM and PET are similar in that they both provide functional imaging employing 18F-FDG. However, PEM is optimized for small body parts and utilizes gentle immobilization of the breast to attain higher spatial resolution (1–2 mm for PEM vs 4–6 mm for PET), as well as minimize the radiation dose by reducing breast thickness. B Breast density, hormone replacement therapy, and menopausal status did not interfere with lesion detection with PEM. These factors are known to affect the glandular tissue of the breast and make interpretation of classic imaging modalities (mammography and MRI) challenging as far as cancer detection is concerned. Thus, with its ability to overcome certain limitations of MRI, PEM was proposed as an appropriate alternative to MRI in the presurgical management of breast cancer patients. When PEM has been directly compared with PET and MRI, the sensitivity was comparable to that of MRI and significantly higher than that of PET, particularly in small tumors). PEM has the potential to play a role in the initial staging of breast cancer, particularly in patients at high risk for multifocal or multicentric disease who desire breast conservation therapy and are unable to undergo staging contrast- enhanced MRI mammography. Evaluating early response to neoadjuvant chemotherapy could be accomplished in earlier stage disease using PEM, because of its superior spatial resolution relative to whole-body scanners. Despite the obvious advantages of PEM technology, a few limitations do apply for PEM scans. Firstly, the specificity of a PEM scan can be attenuated because of high FDG uptake in cases of innate hypermetabolism. Benign breast lesions, such as fibroadenomas in the rapid growth phase, and acute or chron inflammatory processes (e.g., fat necrosis) are known to result in focal FDG uptake; however, these conditions can often be differentiated from malignancy by conventional imaging. Moreover, during a PEM scan, proper positioning of the breast is essential because non-inclusion of the posteriorly located malignancy in the field of view can result in false negative results. Interpretation of PEM scans can also be challenging, especially in lesions that are in close proximity to the chest wall, as well as in larger breasts. Increased breast density has also been reported to result in significantly higher FDG uptake. |