Imaging Principles

CLO 9: Differentiate between size and shape distortion

Size Distortion: increase in the object’s image size compared to its actual size SID OID Increasing SID will decrease magnification Decreasing SID will increase magnification Increasing the OID increases magnification Decreasing the OID decreases magnification Shape Distortion: a misrepresentation of an object’s image shape Central ray alignment of the x-ray tube, part, and image receptor

CLO 8: Analyze the relationships of factors that control and affect spatial resolution

spatial resolution: refers to the smallest object that can be detected in a digital image Increasing focal spot size – spatial resolution decreases Decreasing focal spot size – spatial resolution increases Increasing SID – increase spatial resolution Decreasing SID – decrease spatial resolution Increasing OID – decrease spatial resolution Decreasing OID – increase spatial resolution

CLO 6: Analyze the relationship of factors that control and affect radiographic contrast

Increasing the OID – increase contrast Decreasing the OID – decrease contrast Grids – useful because this will have a less scatter or unwanted exposure on the image: increase the radiographic contrast. The decreased amount of scatter radiation reaching the image receptor results in higher radiographic contrast, *but it requires an increase in mAs. kVp controls radiographic contrastContinue reading “CLO 6: Analyze the relationship of factors that control and affect radiographic contrast”

CLO 2: Discuss practical considerations in setting standards for acceptable image quality

IR/detector manufactures specify an expected range of x-rays exposure that will produce a good-quality image A quality radiographic image accurately represents the anatomic area of interest Brightness, contrast, spatial resolution, and distortion are all factors X-ray tubes that have excessive or insufficient filtration may begin to affect image quality

CLO 1: State the principles of x-ray production

The production of x-rays requires a rapidly moving stream of electrons that are suddenly decelerated or stopped. The cathode is heated, and the electrons are boiled off through the process of thermionic emission. There is a high voltage field between the cathode and anode. The electrons are then attracted to the anode, and move rapidlyContinue reading “CLO 1: State the principles of x-ray production”