Role of Scintimammography in the Diagnosis of Breast Cancer

Abstract

X-ray mammography has been the backbone of early detection of breast cancer. Several large scale systematic studies have shown that judicious use of X-ray mammography can indeed save life. However , though reasonably sensitive, X-ray mammography lacks in specificity leading to many unnecessary biopsies. Scintimammography is a relatively new imaging method to demonstrate cancer tissue in the breast. A radiopharmaceutical agent (Tc-99m Sestamibi) is administered intravenously and images of the breast are taken under a Gamma Camera. There is no need for any manipulation like compression of the breast as required to be done during mammography. The radiopharmaceutical accumulates in the breast in the presence of cancer tissue which can easily be seen in the images. The affinity of the cancer tissue to this radiopharmaceutical is up to 9 times in comparison to normal breast tissue. Several multi centric studies with blinded image interpretation have established the sensitivity and specificity of scintimammography to be above 85 and 90 % respectively as compared to 89 and 14 % respectively for X-ray mammography. The positive and negative predictive values of scintimamography are 70 and 83 % as against 49 and 57 % respectively for X-ray mammography. With the increasing availability of Nuclear Medicine facilities it is expected that more and more patients will benefi with the use of this new imaging modality .