Search results
Results from the WOW.Com Content Network
A radiation source is positioned behind the patient at a standard distance (most often 6 feet, 1,8m), and the x-ray beam is fired toward the patient. In anteroposterior (AP) views, the positions of the x-ray source and detector are reversed: the x-ray beam enters through the anterior aspect and exits through the posterior aspect of the chest.
However, in case the patient cannot stand, the radiograph often needs to be taken with the patient lying in a supine position (called a "bedside" radiograph) with the X-rays coming from above ("anteroposterior" or "AP"), and geometric magnification will then cause for example the heart to appear larger than it actually is because it is further ...
The gantry of an external beam radiotherapy machine moves a radiation source around a patient. A linear accelerator (linac) is built into the top part of the gantry in the photo at the right. The rectangular screen on the right side of the gantry is a cone beam x-ray detector, which is used to help position a patient prior to treatment.
Image-guided radiation therapy (IGRT) is the process of frequent imaging, during a course of radiation treatment, used to direct the treatment, position the patient, and compare to the pre-therapy imaging from the treatment plan. [1]
The radiograph for each mastoid is taken separately. Schuller's view serves as an alternate view to the Law projection which uses a 15° angle of patient's face toward the image receptor and a 15° caudal angulation of the computed radiography (CR) to achieve the same result, a lateral mastoid air cells view without overlap of the opposite side.
X-ray computed tomography operates by using an X-ray generator that rotates around the object; X-ray detectors are positioned on the opposite side of the circle from the X-ray source. A sinogram (left) and an image sample (right). [1] Picture of a CT scout (scanogram or topogram) as used for planning every scan slice.
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").
This is the most basic form of conventional tomography. The X-ray tube moved from point "A" to point "B" above the patient, while the detector (such as cassette holder or "bucky") moves simultaneously under the patient from point "B" to point "A". [5] The fulcrum, or pivot point, is set to the area of interest. In this manner, the points above ...