MEDRADSC 3K03 Lecture Notes - Lecture 6: Mediastinum, Hounsfield Scale, Atomic Number

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 3K03
• Professor: Lyndsay Simmons

Document Summary

Image center: when reconstructing image, in addition to identifying dfov diameter, must specify which part of sfov we want, specify location, cartesian coordinates. Just want to reformat a small part (just the right kidney for example), input the values retrospectively into the ras coordinates in order to recreated the image. Ct numbers: each pixel of image has a ct number, ct numbers are related to linear attenuation coefficient of the measured tissue ( t) that make up the slice, ct number = ( t - w / w ) . Imagine if we displayed a matrix of ct numbers for physicians to scan and look for a(cid:271)(cid:374)o(cid:396)(cid:373)alities : brightness levels corresponds to ct numbers, relationship between ct numbers and shades of gray = windowing. Lac and energy dependence: has an inverse relationship. Lac is affected by several factors: energy, atomic number, density, more importantly => energy of the beam.