Английский язык. Английский язык,. 1 в целях подготовки к зачету (начать оформлять, как это делали, но пока не требуется отправлять на проверку)
 Скачать 174.46 Kb.
|
4 How should I prepare?You should wear comfortable, loose-fitting clothing to your exam. You may need to wear a gown during the procedure Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images. Leave them at home or remove them prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal underwire. You may be asked to remove any piercings, if possible. You will be asked not to eat or drink anything for a few hours beforehand, if contrast material will be used in your exam. You should inform your physician of all medications you are taking and if you have any allergies. If you have a known allergy to contrast material, your doctor may prescribe medications (usually a steroid) to reduce the risk of an allergic reaction. To avoid unnecessary delays, contact your doctor before the exact time of your exam. Also inform your doctor of any recent illnesses or other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an adverse effect. Women should always inform their physician and the CT technologist if there is any possibility that they may be pregnant. See the CT Safety During Pregnancy page for more information. If you are breastfeeding at the time of the exam, ask your doctor how to proceed. It may help to pump breast milk ahead of time and keep it on hand for use until contrast material has cleared from your body, about 24 hours after the test. However, the most recent American College of Radiology (ACR) Manual on Contrast Media reports that studies show the amount of contrast absorbed by the infant during breastfeeding is extremely low. For further information please consult the ACR Manual on Contrast Media and its references.
5 What does the equipment look like?The CT scanner is typically a large, donut-shaped machine with a short tunnel in the center. You will lie on a narrow examination table that slides in and out of this short tunnel. Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is located in a separate control room. This is where the technologist operates the scanner and monitors your exam in direct visual contact. The technologist will be able to hear and talk to you using a speaker and microphone.
6 How does the procedure work?There are many similarities between conventional x-ray imaging and CT scanning. During conventional x-ray imaging, a single x-ray beam source sends x-rays through the body. A detector plate captures the x-rays that come out of the body. Based on the amount of x-rays blocked by the body organs, the image will appear in different shades of gray. For example, bones appear white on the x-ray while air is relatively black. For CT scans, multiple x-ray beam sources and sets of x-ray detectors spin around the body at high speed. The x-ray beam sources send multiple small high-energy x-ray beams through the body. The detectors capture those x-rays that come out of the body. During the examination, you will lie on a table that moves through the CT scanner so that the x-ray beams can examine different areas of the body. Then, a fast computer will take the information gathered from the scanner to produce images of the body. The computer processes a large volume of CT scan data to create two or three-dimensional images of the body. Radiologists will analyze these images using sophisticated computer programs and high-quality monitors to detect diseases in the body. When a contrast material is introduced to the bloodstream during the procedure, it clearly defines the blood vessels being examined by making them appear bright white. |