Routine CT scanning protocols - Essay Example

The protocols given below are used in the Department of Radiology and Molecular Imaging in king Abdul Aziz Hospital (KAH) in Saudi and in Sir Charles Gardean Hospital (SCGH) in Perth, WA. A 64-slice Siemens multi-detector computed tomography (MDCT) was recently introduced in KAH and is used for all CT procedures, including routine procedures. SCGH also has a 64-slice GE, which is used for all CT procedures. In any x-ray system, the energy of the x-ray beam depends on its tube potential (kVp).

Changes in kVp results in changes in radiation dose, image noise and image contrast. Radiation dose can be reduced up to 30% if kVp is reduced from 120 to 100. In addition, lowering the kVp to 100 during CTA for PE improves visualization of sub segmental arteries (Kubo et al 2008). A study by Hausleiter et al 2006, showed that in a 64-slice CT cardiac procedure, a 100 kV protocol used instead of a 120 kV protocol along with an ECG gated technique, resulted in a 64% reduction in the effective dose.

In liver imaging, 120 kVp is suitable and usually preferred than 140 kVp in order to reduce patient dose. Although it is said that that by reducing the kVp the image noise increases, the process leads to the improvement of tissue contrast (Laghi 2007). Kim et al 2009, in their study, aimed to assess the effect on image quality and radiation dose with low-kilovoltage protocols by chest multidetector computed tomography (CT) examinations in adults.  The study included 210 patients (83 women and 127 men with a mean age of 56.1 years). These patients were randomly assigned to one of three protocol groups: (1) protocol A (the standard protocol) with 120 kilovolt (peak) (kV[p]) and 100 effective milliampere-second (eff mA s); (2) protocol B, with 100 kV (p) and 140 eff mA s; and (3) protocol C, with 80 kV(p) and 180 eff mA s.

Each group had 70 patients. A marginal