MAMMOGRAPHY COMPLETE 2024 QUESTIONS WITH 100% ACCURATE SOLUTIONS

MAMMOGRAPHY COMPLETE 2024 QUESTIONS WITH 100% ACCURATE SOLUTIONS Two screening mammography views Craniocaudal and Mediolateral When is ultrasound often used for mammography? To differentiate cysts from solid masses and also for biopsy needle guidance When is MRI often used for mammography? Can differentiate from benign and malignant tumors. Used for diagnosis, staging, biopsy guidance, and in some cases screenings. When is mammoscintigraphy using Tc-99m sestamibi used? In the evaluation of suspected breast cancer in patients for whom mammography is nondiagnostic, equivocal, or difficult to interpret (eg scar tissue, dense breast tissue, implants, or sever dysplastic disease). Also used to assist in identifying multicentric and multifocal carcinomas in patients with tissue diagnosis of breast cancer. Why are very low kVs used in mammography? The contrast differences between cancerous and normal tissue are very small but more noticeable at 10-15 keV. Typical mammography focal spot sizes 0.3 mm (lg) and 0.1 mm (sm) mA limits for mammography tubes 100 mA for lg fs, 25 mA for sm fs. Or, for W anode, 200 mA for lg and 50 mA for sm Why are Mo and Rh good target materials for anodes? Mo produces characteristic x-rays of 17.5 and 19.6 keV, Rh of 20.2 and 22.7 keV Why is W being used as an anode material in modern mammography units? Increased, x-ray production efficiency (higher Z), better heat loading (higher melting point). In addition, digital detectors have extended exposure latitude and because post-acquisition image processing can enhance contrast, characteristic radiation from Mo or Rh is not as important in digital mammography. Reduces dose (~65% of Mo?) Specs on mammography anodes Angles from 0-16 degrees (effective anode angle at least 22 degrees for a 24x30 cm field), SID of about 65 cm. How is the heel effect used in mammography? The cathode (greatest intensity) is positioned over the chest wall and the anode over the anterior to achieve uniform coverage to the detector What is another reason the x-ray tube is oriented front-back in mammography? It decreases the equipment bulk near the patient's head. The anode is kept at ground and the cathode is set to highest negative voltage to reduce off-focal radiation. "Half-field" x-ray beam geometry Used to avoid exposure of patients' torsos and maximize breast tissue near chest wall imaged. Achieved by fixed collimation at the x-ray tube head. The central axis of the x-ray beam is directed at the chest wall edge of the receptor and perpendicular to the pl