in the oxyphil cells of the abnormal glands retaining the 99mTc are seen with the gamma camera. This imaging method will detect 75 to 90 percent of abnormal parathyroid glands in primary hyperparathyroidism. An endocrine surgeon can then perform a focused parathyroidectomy (less invasive than traditional surgery) to remove the abnormal gland. Radioguided surgery of the parathyroids Following administration, 99mTc MIBI collects in overactive parathyroid glands. During surgery, the surgeon can use a probe sensitive to gamma rays to locate the overactive parathyroid before removing it. Thyroid imaging Several case reports have demonstrated that 99mTc MIBI scan may be useful to differentiae the sub-type of amiodarone-induced thyrotoxicosis. Lack of MIBI uptake in the thyroid is compatible with a form of thyroiditis (type-2 AIT) which may respond to treatment with steroids. Breast imaging The drug is also used in the evaluation of breast nodules. Malignant breast tissues concentrate 99mTc MIBI to a much greater extent and more frequently than benign disease. As such, limited characterization of breast anomalies is possible. Scintimammography has a high sensitivity and specificity for breast cancer, both more than 85%. More recently, breast radiologists administer lower doses of 99mTc sestamibi (approximately ) for Molecular Breast Imaging (MBI) scans which results in a high sensitivity (91%) and high specificity (93%) for breast cancer detection. It however carries a greater risk of causing cancer, making it not appropriate for general breast cancer screening in patients. The last reference listed refers to a dose, which is given with the Dilon single-head system, which requires a higher dose since only one camera is utilized (meaning the camera needs to be able to see through more tissue). A dose, which is used in the other two commercially available MBI systems is essentially equivalent to a mammogram () or a tomosynthesis exam (). In order to keep the radiation doses to patients as low as reasonably achievable, MBI is usually limited to women with dense breast tissue, where the medical benefit of the scan outweighs the potential risk of radiation exposure. For the same reason, the administered activity is kept low. This can potentially result in noisy images, which in turn causes inconclusive mammograms. Researchers continue to devote their time to improving the technology, changing scan parameters, and reducing dose to patients. References External links Cardiolite official page Molecular Breast Imaging The Sestamibi Scan for Hyperparathyroidism on: Parathyroid.com Radiopharmaceuticals Bristol Myers Squibb Technetium-99m