RIU 434 Lecture Notes - Lecture 1: Beam Divergence, Mammography, Shallow Focus

• School: GVSU
• Department: Radiation and Imaging - Ultrasound
• Course: RIU 434
• Professor: Amy Winston

Document Summary

Patients that have bus before mammography: * people who should not be exposed to radiation, pregnant, under 30, follow up past bus(palpable) known abnormality, palpable abnormalities- within 6 months after last mammogram. Advantages to bus: able to distinguish different types of breast tissue, not as painful, able to distinguish between solid and cystic, prevent unnecessary biopsy, targeted examinations, help with correlation, can visualize very dense breast. Limitations of bus: extremely operator dependant, essential to use appropriate equipment. Output power: the amount of voltage applied to the transducer to create a sound wave; determines patient exposure, alara, controls the brightness of the image, too bright= decrease op, too dark= increase op. Elevational plane focus: focus in the short axis or elevational plan of the transducer. 1-d transducers have a fixed elevational plane focus: most clinical transducers, high freq- shallow focus, low freq- deeper focus 7-12 mhz= 1-2 cm depth, 10mhz= 1. 5cm elevation plane focus.