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  1. 3 days ago · The advantage of a CT scan is that x-rays detection is not impacted by emission photons. Consequently, a CT scan can be performed after the radiopharmaceutical injection. A CT scan can be done for diagnostic purposes, using regular tube current, or just for attenuation correction (i.e., a low-dose CT) with low tube current (typically 10–30 mAs).

  2. 1 day ago · Patients requiring a chest CT scan, as part of their standard workup for the evaluation of PE, were approached for the study (EVMS IRB# 15-01-FB-0006). Using a pediatric phantom, several images were obtained at different CT scan settings in order to develop the ultra-low dose CT scan (ULTRA) protocol that was compared to the CARE dose.

  3. 1 day ago · However, the radiation dose from a single CT scan is relatively low. The risk is thought to be very small, with the chances of developing a fatal cancer due to a CT scan estimated at about 1 in 2,000. It's important to note that the benefits of a medically necessary CT scan typically outweigh the small potential risk from radiation exposure.

    • Overview
    • What is a CT scan?
    • What is a CT scan with contrast?
    • Why is a CT scan performed?
    • What’s the CT scan procedure like?
    • What are the risks associated with a CT scan?
    • What do CT scan results mean?
    • Takeaway

    For certain medical conditions, imagery from an X-ray or ultrasound test isn’t enough. A computed tomography (CT) scan provides a more detailed view of your tissues, blood vessels, and bones.

    Doctors and other healthcare professionals have years of training in their field, but there are still many things they can’t diagnose simply by looking at or listening to your body. That’s where tests like a CT are helpful.

    A CT scan uses computers and rotating X-ray machines to create cross-sectional images of the body. These images provide more detailed information than typical X-ray images. They can show the soft tissues, blood vessels, and bones in various parts of the body.

    A CT scan may be used to visualize the:

    •head

    •shoulders

    •spine

    •heart

    CT scans can provide detailed images of bones, tissues, and even blood vessels inside your body.

    However, the images that are produced by these scans appear in shades of blacks and grays. It can be difficult at times even for a trained eye to differentiate one tissue type from another in certain situations.

    Contrast dyes contain barium or iodine and can be given in a number of ways, including orally and intravenously (in your vein). These dyes increase the contrast level and resolution of the final images produced with the CT scan for a more exact diagnosis.

    However, there are a few risks associated with using contrast dyes. For example, there’s a higher chance of allergic reactions to the dyes, and they’re also not good for your kidneys.

    Still, every CT scan exposes you to a certain level of radiation, and a CT scan with contrast may produce better results than one without. It may also prevent the need for a repeated scan.

    Below is a comparison of when CT scans may be used with or without a contrast dye.

    A CT scan has many uses, but it’s particularly well-suited for diagnosing diseases and evaluating injuries. The imaging technique can help your doctor:

    •diagnose infections, muscle disorders, and bone fractures

    •pinpoint the location of masses and tumors, including cancer

    •study the blood vessels and other internal structures

    •assess the extent of internal injuries and internal bleeding

    •guide procedures, such as surgeries and biopsies

    How to prepare for a CT scan

    CT scans don’t require much preparation. If needed, you can do a CT scan with or without contrast very quickly. In fact, this happens in most cases where a CT scan is needed to diagnose traumatic injuries or a stroke. If you’re scheduled for a CT scan with contrast dye, it may help to refrain from eating solid foods for up to 4 hours before your test. This is especially true if your CT scan is being done to get images of your abdomen. If your doctor is using oral contrast for your CT scan, you’ll probably be given the contrast before the day of your scan and instructed on how to prepare and drink it. Generally, you will want to start drinking the solution within an hour or two of your scan, drinking a portion of the solution every 15 minutes. Your doctor or radiologist will give you specific instructions. If you’re having intravenous (IV) contrast, a catheter will be inserted into your vein when you arrive at the testing facility. Otherwise, the only preparations you need to take before a CT scan are to remove metallic objects and medication devices from your body. This includes: •jewelry and piercings •watches •glasses •hairpins •hearing aids •dentures •bras with underwire •“antimicrobial” clothing with silver technology •nicotine patches •other medication patches

    What to expect during a CT scan

    When you arrive for your CT scan, you’ll be asked to change into a hospital gown. The technician doing your scan may insert an IV catheter in your arm or leg and ask whether you have removed any metal devices or medication patches prior to your arrival. They may also review why you’re having the scan, any allergies you may have, and other special instructions. When it’s time to begin the scan, you’ll be positioned on a long narrow table, and you may be secured in place with velcro straps or other safety devices. The table will slide in and out of the circular scanner depending on which parts of your body need to be visualized. The technician will leave the room before operating the scanner and may give you instructions over an intercom. As the table moves in and out of the scanner, the machine will rotate around you making a loud noise. You may be asked to hold your breath or maintain certain positions. Otherwise, you should hold as still as possible to prevent the scanner from capturing blurry images. The entire process should take between 20 minutes and 1 hour.

    After your CT scan

    Once the CT scan is over, the images are sent to a radiologist for examination. A radiologist is a doctor who specializes in diagnosing and treating conditions using imaging techniques, such as CT scans and X-rays. Your doctor will follow up with you to explain the results.

    There are very few risks associated with a CT scan. These include:

    •exposure to radiation

    •allergic reactions to contrast dyes

    •increased cancer risk with multiple scans

    If you have an allergy to contrast dye, your doctor may choose to do the scan without contrast. If using contrast is absolutely necessary, your doctor may treat you with steroids or other medications to help prevent an allergic reaction.

    After the scan, the contrast dye you were given will be eliminated naturally from your body through your urine and stool. Contrast dye can cause some strain to the kidneys, so you may be instructed to drink a lot of water after your exam.

    CT scan results are considered typical if the radiologist didn’t see any of the following in the images:

    •tumors

    •blood clots

    •fractures

    •other atypical characteristics

    If any atypical characteristics are detected during the CT scan, you may need further tests or treatments depending on the type of atypicality found.

    CT scans are an excellent tool for diagnosing problems with soft tissues, blood vessels, and other body parts that can’t be seen with X-ray or ultrasound imaging.

    These painless scans don’t require much preparation and can be done quickly in emergency situations. A CT scan takes less than an hour to do, but you may not get results right away, depending on who is interpreting the results.

  4. Oct 31, 2019 · Summary. A computed tomography (CT) head scan uses X-rays to develop a 3D image of the skull, brain, and other related areas of the head. A CT scan of the head can provide more detail than a ...

  5. Apr 21, 2021 · A computed tomography (CT) scan, commonly referred to as a CT, is a radiological imaging study. The machine was developed by physicist Allan MacLeod Cormack and electrical engineer Godfrey Hounsfield.[1][2][3] Their development awarded them the Nobel Prize in Physiology or Medicine in 1979.[4] The first scanners were installed in 1974. Since then, technological advances and math have allowed ...

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  7. www.webmd.com › cancer › what-is-a-ct-scanWhat Is a CT Scan? - WebMD

    Nov 1, 2023 · CT scans use X-rays, which produce ionizing radiation. Research shows that this kind of radiation may damage your DNA and lead to cancer. But the risk is very small – your chances of developing ...

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