BME 229 Lecture Notes - Lecture 2: Electromagnetic Spectrum, Radiography, Positron Emission Tomography

• School: Ryerson University
• Department: Biomedical Engineering
• Course: BME 229
• Professor: Jahan Tavakkoli

Document Summary

Bme229 unit 2: atomic structure and radioactive decay. Electromagnetic (em) radiation: no mass, unaffected by electrical or magnetic fields. Trajectory can be altered by interaction with matter: absorption reduction of the radiation. Characterized by amplitude, wavelength (), frequency (f), and period (t) = vt v = f: where speed = v or c. Frequency expressed in hz (1hz = 1 cycle/sec = 1 sec-1) For em waves, v is the speed of light. Energy is carried by oscillating electrical and magnetic fields travelling through space at the speed of light. Em spectrum: note the overlap between types of waves, radio waves. I(cid:374)(cid:272)o(cid:396)(cid:396)e(cid:272)tly (cid:272)alled (cid:862)heat (cid:449)a(cid:448)es(cid:863: produced by hot objects and molecules, readily absorbed by most materials, visible light, most sensitive at about 5. 5 * 10-7 m (yellow-green: different wavelengths correspond to different colors, ultraviolet, covers about 4*10-7 m to. Sun is a source of uv light: most uv light from the sun is absorbed in the stratosphere by ozone.