Gamma imaging

The Role of Ultrasound as a Diagnostic Tool for Sarcopenia

“…p ]Ultrasound echogenicity has been particularly highlighted as a technique to measure muscle quality. Ultrasound echogenicity refers to the capacity of any tissue to reflect and absorb ultrasound waves, and can be calculated using grayscale analysis derived from ultrasound imaging ( 36 ). In essence, the whiter the image the higher the proportion of slow-twitch muscle fibre and intra-muscular adipose tissue; high ultrasound echogenicity values have been correlated with lower muscle quality and grip strength ( 21 , 22 , 37 ).…”

Additive manufacture of custom radiation dosimetry phantoms: An automated method compatible with commercial polymer 3D printers

“…A central HU, termed window level, and HU range of interest, window width, are selected, and HU values outside this range are compressed to the window maximum or minimum levels (for display only) [12]. This accommodates the fact that most biological tissues occupy a narrow range of HU values and so feature relatively low contrast.…”

The role of computed tomography in musculoskeletal trauma

“…An estimated 70 million CT scans are performed annually in the United States, so although a detailed knowledge of CT physics is not necessary for clinicians, an understanding of the basic principles and terminology are useful (Larson et al, 2011b). Clinicians interested in a more detailed review of the technology are advised to consult the following: Flohr et al (2005) and Alisy-Roberts (2008).…”

“…As a digital technique, each CT image is made up of thousands of tiny pixels (picture elements). Each pixel (or the 3-D equivalent voxel ), which forms the grey CT image, is shaded according to the average attenuation of the X-ray beam as it passes through the different tissues within that voxel (Alisy-Roberts, 2008). These relatively different attenuations are quantified as Hounsfield Units (HU) by the computer.…”

“…fat versus muscle, blood versus free fluid). However, the human eye can only differentiate 50 shades of grey, so CT images must be windowed , limiting the displayed range of HU, in order to show maximum tissue detail (Figure 1; Alisy-Roberts, 2008).

Figure 1.Different windowing (to show different tissues preferentially) and multi-plain reformats (to show different anatomical plains) used for computed tomography (CT) image analysis.

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