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CT scans can expose patients to levels of radiation 100-500 times higher than traditional x-rays, with higher radiation doses producing better resolution imaging. [37] While easy to use, increases in CT scan use, especially in asymptomatic patients, is a topic of concern since patients are exposed to significantly high levels of radiation.
The radiation doses received from CT scans is variable. Compared to the lowest dose X-ray techniques, CT scans can have 100 to 1,000 times higher dose than conventional X-rays. [149] However, a lumbar spine X-ray has a similar dose as a head CT. [150]
Computed tomography or CT scan (previously known as CAT scan, the "A" standing for "axial") uses ionizing radiation (x-ray radiation) in conjunction with a computer to create images of both soft and hard tissues. These images look as though the patient was sliced like bread (thus, "tomography" – "tomo" means "slice").
Electron beam computed tomography (EBCT) is a fifth generation computed tomography (CT) scanner in which the X-ray tube is not mechanically spun in order to rotate the source of X-ray photons. This different design was explicitly developed to better image heart structures that never stop moving, performing a complete cycle of movement with each ...
Quantitative CT scans are primarily used to evaluate bone mineral density at the lumbar spine and hip. In general, solid phantoms placed in a pad under the patient during CT image acquisition are used for calibration. These phantoms contain materials that represent a number of different equivalent bone mineral densities.
Terahertz radiation: THz-CT Thermoacoustic imaging: Photoacoustic spectroscopy: TAT Ultrasound-modulated optical tomography: Ultrasound: UOT Ultrasound computer tomography: Ultrasound: USCT Ultrasound transmission tomography: Ultrasound: X-ray computed tomography: X-ray: CT, CAT scan 1971 X-ray microtomography [15] X-ray: microCT Zeeman-Doppler ...
In conventional CT machines, an X-ray tube and detector are physically rotated behind a circular shroud (see the image above right). An alternative, short lived design, known as electron beam tomography (EBT), used electromagnetic deflection of an electron beam within a very large conical X-ray tube and a stationary array of detectors to achieve very high temporal resolution, for imaging of ...
Historically the procedure involved the injection of a radiocontrast agent into the cervical or lumbar spine, followed by several X-ray projections. Today, myelography has largely been replaced by the use of MRI scans , although the technique is still sometimes used under certain circumstances – though now usually in conjunction with CT ...