High Resolution Breast Gamma Emission Imaging System
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: This proposal is directed toward the design and development of a dedicated breast scanner (that is, developed and used with this one purpose in mind) for use in nuclear medicine that would be easier and less costly to use, and more accurate than current gamma ray imaging cameras. (Gamma rays are a kind of X ray.) Although conventional x-ray mammography provides the ability to see detail ("spatial resolution") ranging from .01 to 0.1 millimeters to visualize breast lesions and any structural changes related to anatomy, surgical biopsies are generally required to distinguish benign (non-cancerous) from malignant (cancerous) lesions. However, approximately 400,000 of the 600,000 lesions (also called lumps, masses, or tumors) removed at surgery in the United States each year prove to be benign. An imaging technique to determine whether a lesion is malignant or benign without requiring a biopsy would thus be of great significance to how breast cancer is diagnosed and monitored. If, in fact, it could be established whether a lesion is malignant or benign without requiring a biopsy, the savings, both psychologically and monetarily, would be enormous. 
 
 
 
 
 
 
 
 Preliminary studies have shown that non-invasive nuclear medicine imaging techniques, where a pharmaceutical to which a trace amount of radioactivity is attached is introduced into the body usually through an intravenous injection, can allow us to determine biochemical characteristics of a lesion indicating whether it is benign or malignant with an accuracy greater than 95%. Current nuclear medicine studies are conducted either with gamma ray emitting radiopharmceuticals based on a common radioisotope known as Tc-99m, or with specially produced radiopharmaceuticals that emit energy particles known as positrons. Our idea is that a gamma imaging scanner designed exclusively for the breast could achieve an improvement, by a factor of three, in spatial resolution over current gamma emission imaging systems, thereby yielding significant improvements in the sensitivity (the ability to detect a mass) and specificity (the ability to distinguish benign from cancerous masses) of breast imaging. Currently, lesions smaller than about 8 millimeters are not seen in conventional nuclear medical scans. The high resolution of the scanner we propose to develop should enable visualization of lesions in the 3-8 millimeter range for the first time, and, at the same time, significantly reduce the incidence of false negatives (that is, failing to detect a mass which is present in the breast), a major concern at the present time. The scanner relies on a cylindrical design using high-resolution semiconducting detectors which have only recently become practical for applications of this type. We propose to design a system where semiconducting detectors will be tiled on a cylindrical surface to cover a larger portion of the breast. Use of semiconducting detectors instead of currently used scintillation detectors more commonly in use in nuclear medicine will also eliminate a drawback of current scanners which makes it very difficult to image close to the chest wall. 
 
 
 
 
 
 
 
 With our proposed detectors it will become possible to image very close to the chest wall at the same time avoiding any background radiation from the heart. In addition, the proposed scanner will attain a resolution similar to that attainable with larger, more expensive dedicated positron emission mammography systems, but at a significantly reduced cost for the radiopharmaceuticals.