What is a CT scan?

计算机断层扫描通常被称为CT扫描. CT扫描是一种诊断成像程序，它使用了 X-rays 计算机技术可以产生人体内部的图像. 它能显示身体任何部位的详细图像, including the bones, muscles, fat, organs and blood vessels.

CT扫描比标准的x光扫描更详细. 在标准的x射线中，一束能量瞄准被研究的身体部位. A plate behind the body part captures the variations of the energy beam after it passes through skin, bone, muscle and other tissue. 虽然从常规的x射线中可以获得很多信息, 关于内部器官和其他结构的很多细节是无法获得的.

在CT中，x射线束绕着身体做圆周运动. This allows many different views of the same organ or structure and provides much greater detail. The X-ray information is sent to a computer that interprets the X-ray data and displays it in two-dimensional form on a monitor. 更新的技术和计算机软件使三维图像成为可能.

CT扫描可以帮助诊断肿瘤, investigate internal bleeding, or check for other internal injuries or damage. CT can also be used for a tissue or fluid biopsy.

为什么CT扫描有时要按对比排序?

CT scans may be done with or without contrast. Contrast refers to a substance taken by mouth or injected into an IV line that causes the particular organ or tissue under study to be seen more clearly. Contrast examinations may require you to fast for a certain period of time before the procedure. 你的医生会在手术前通知你.

You will need to let your doctor know if you have ever had a reaction to any contrast media and/or any kidney problems. A reported seafood allergy is not considered to be a contraindication for iodinated contrast. 如果你有任何身体状况或最近的疾病，告诉你的医生.

How do I prepare for a CT scan?

If you are having a computed tomography angiography (CTA) or a virtual colonoscopy，您在预约时将会得到具体的指示.

PRECAUTIONS:如果你怀孕了或认为你可能怀孕了, 请在安排检查前咨询您的医生.

CLOTHING你可能会被要求换上病号服. If so, a gown will be provided for you. 请摘下所有的穿孔，并将所有珠宝和贵重物品留在家中.

CONTRAST MEDIA: Contrast may be indicated for your exam. The contrast media improves the radiologist’s ability to find structures that are abnormal and understand normal anatomy better.

• 有些患者不应使用碘基造影剂. If you have problems with your kidney function, please inform your radiologist in advance. We may be able to perform the scan without the contrast media or find an alternate imaging exam.
• 最常见的CT扫描类型是双重对比研究, which will require you to drink a contrast media before your exam begins in addition to the IV contrast. The more contrast you are able to drink, 放射科医生看到的消化道图像越清晰.

ALLERGY: Please inform the access center representative when you schedule your scan if you have had an allergic reaction to any contrast media. IV contrast will not be administered if you have had a severe or anaphylactic reaction to any contrast media in the past. Mild to moderate reactions warrant a plan that includes taking medication prior to the CT examination. 这些计划将在您安排考试时与您详细讨论. Any known reactions to a contrast media should be discussed with your personal physician.

EAT/DRINK: If your study was ordered without 相比之下，你可以在考试前吃、喝和服用处方药物.

If your doctor orders a CT scan with 相反，在CT扫描前三小时不要吃任何东西. We encourage you to drink clear liquids. 您也可以在检查前服用处方药物.

DIABETICS: People with diabetes 应该在扫描前三小时吃清淡的早餐或午餐吗. Depending on your oral medication for diabetes, 您可能会被要求停止使用药物48小时 after the CT examination. 详细说明将在您的检查后给出.

MEDICATION所有推荐十大正规网赌平台都可以照常服用处方药物.

What are the risks of a CT scan?

If you are pregnant or think you may be pregnant, you should notify your health care provider.

在CT扫描中使用的辐射剂量很小. You may want to ask your doctor about the amount of radiation used during the CT procedure and the risks related to your particular situation.

If you are claustrophobic or tend to become anxious easily, tell your doctor ahead of time. You may be prescribed a mild sedative to take before the procedure to make you more comfortable.

What happens during a CT scan?

CT scans may be performed on an outpatient basis or as part of your stay in a hospital. 治疗方法可能会根据你的病情和医生的做法而有所不同. Generally, CT scans follow this process:

• 你可能会被要求换上病号服. If so, a gown will be provided for you. 将提供一个储物柜来保管所有个人物品. 请摘下所有的穿孔，并将所有珠宝和贵重物品留在家中.
• 如果你要做对比手术, 在手或手臂上开始静脉注射造影剂. 对于口服造影剂，医生会给你一种液体造影剂，让你吞咽. 在某些情况下，可以在直肠造影.
• You will lie on a scan table that slides into a large, circular opening of the scanning machine.
• 技术人员将在另一个房间，那里有扫描仪的控制. 然而，你将通过一扇窗户一直看到技术专家. Speakers inside the scanner will enable the technologist to communicate with and hear you. You may have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.
• As the scanner begins to rotate around you, x射线会在短时间内穿过人体. 你会听到咔哒声，这是正常的.
• The X-rays absorbed by the body’s tissues will be detected by the scanner and transmitted to the computer. The computer will transform the information into an image to be interpreted by the radiologist.
• 在手术过程中保持不动是很重要的. 在手术过程中，你可能会被要求在不同的时间屏住呼吸.
• If contrast media is used for your procedure, 当造影剂注入静脉管线时，你可能会感觉到一些影响. These effects include a flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments.
• 如果你有呼吸困难，你应该通知技师, sweating, numbness or heart palpitations.
• 程序完成后，您将离开扫描仪.
• 如果静脉注射是为了注射造影剂，那么静脉注射线将被移除.
• While the CT procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, 特别是在最近受伤或侵入性手术的情况下, such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after a CT scan?

• 如果在您的手术过程中使用了造影剂, you may be monitored for a period of time for any side effects or reactions to the contrast, such as itching, swelling, rash or difficulty breathing.
• If you notice any pain, redness and/or swelling at the IV site after you return home following your procedure, you should notify your doctor, 因为这可能表明感染或其他类型的反应.
• CT扫描后通常不需要特殊的护理. You may resume your usual diet and activities unless your doctor advises you differently.
• 你的医生可能会在手术后给你额外的或替代的指示, depending on your particular situation.

What are some of the advances in CT technology?

Advances in CT technology include:

• 高分辨率CT:这种类型的CT扫描使用非常薄的切片(小于0.1 inches), 在特定条件下，哪些能有效地提供更多的细节, such as lung disease.
• 螺旋或螺旋CT:在这种类型的CT扫描期间, 推荐十大正规网赌平台和x射线都连续移动, with the X-ray beam circling the patient. 与标准CT扫描相比，获得图像的速度要快得多. The resulting images have greater resolution and contrast, providing more detailed information. Multidetector-row helical CT scanners may be used to obtain information about calcium buildup inside the coronary arteries of the heart.
• Ultrafast CT (也称为电子束CT):这种类型的CT扫描产生图像非常快, 这样就创造了一种身体活动部位的“电影”, such as the chambers and valves of the heart. This scan may also be used to obtain information about calcium buildup inside the coronary arteries of the heart, but the helical scanners are much more common.
• Computed tomographic angiography (CTA)血管造影术(或动脉造影术)是血管的x射线图像. A CT angiogram uses CT technology rather than standard X-rays or fluoroscopy to obtain images of blood vessels — for example, the coronary arteries of the heart.
• Combined positron emission tomography and CT (PET/CT): The combination of CT and positron emission tomography technologies into a single machine is referred to as PET/CT. PET/CT combines the ability of CT to provide detailed anatomy with that of PET to show cell function and metabolism in order to offer greater accuracy in the diagnosis and treatment of certain types of diseases, particularly cancer. PET/CT也可用于评估以下情况 epilepsy, Alzheimer’s disease and coronary artery disease.