The Risks And Hazards Associated With Risk Reduction And Safety Will Be Discussed

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Extreme caution is exercised when examining pregnant patients, as the health of both the mother and foetus is considered. The ALARA ( As Low As Reasonably Practicable) principle applies across all imaging modalities. This essay looks at Computed Tomography(CT), Magnetic Resonance Imagine (MRI) and Ultrasound (US), modalities used disease and pathology diagnosis. It will look at the scientific principles. Comparing the risks and hazards associated with each modality when examining pregnant patients. Risk reduction and safety will be discussed.

Scientific Principles
Computed Tomography
CT is cross-sectional image acquisition using the x-ray beam transmission measurements. Unlike MRI and Ultrasound, CT produces ionizing
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Compton Scattering is when an electron causes an x-ray photon to change direction (Ball, Moore& Turner, 2008). The change in direction causes energy loss, resulting in longer wavelengths. The energy lost by the photon is gained by the electron, this electron is ejected from the electron shell.
CT can be described as an x-ray tube and detectors, located in the gantry, parallel to each other, able to rotate 360° in a continuous motion, illustrated in Appendix 1.4. The continuous motion allows for the collection of an ongoing stream of information. The development of slip rings eliminated the use of cables, allowing the continuous rotation, increasing scan time (Kalender, 2011)
The patient table moves the patient through the gantry, allowing for patient positioning without moving the body. The detectors convert and amplify the x-ray beams into electric signals. The computer knows the exact position of the tube and detectors, along with the number of pixels the beam went through and the dose measurement. Each pixel corresponds to a Hounsfield unit; this is the attenuation value of a corresponding voxel (Opplet, 2005). The attenuation value is compared to that of water. Hounsfield units represent shades of grey; this quantifies beam attenuation. These units are interpreted using computer algorithms, producing an image.
Magnetic Resonance Imaging
MRI is the acquisition of cross-sectional images using

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