You can’t walk into an imaging center and request a CT scan on your own. In most cases, you need a doctor or other licensed provider to order one for you, and your insurance may require advance approval before the scan is scheduled. The process typically involves a medical visit, an order, possible insurance authorization, and then the scan itself.
Who Can Order a CT Scan
Any treating physician can order a CT scan, including your primary care doctor, an emergency room physician, or a specialist like a neurologist or orthopedic surgeon. Nurse practitioners, clinical nurse specialists, and physician assistants can also order CT scans under the same rules. The key requirement is that the provider ordering the scan is actively treating you for a specific medical problem and will use the results to guide your care.
If you think you need a CT scan, the first step is making an appointment with whichever provider is managing your condition. In an emergency department, CT scans are ordered on the spot when a situation calls for rapid imaging, such as after a head injury or when a stroke is suspected.
Reasons Providers Order CT Scans
CT scans produce detailed cross-sectional images of bones, organs, soft tissue, and blood vessels with far greater clarity than standard X-rays. Providers use them to diagnose injuries and diseases, plan surgeries or other procedures, and monitor how well treatments like chemotherapy are working.
That said, a CT scan isn’t always the first choice. Ultrasound and MRI don’t use radiation at all, so providers weigh whether one of those could answer the same clinical question. You’re most likely to get a CT when the situation involves trauma, suspected internal bleeding, kidney stones, appendicitis, blood clots in the lungs, or when fast, detailed imaging of bones and organs is needed. MRI is generally preferred for soft tissue detail in joints or the brain when there’s no time pressure.
Insurance and Prior Authorization
Many insurance plans require prior authorization before they’ll cover a CT scan, especially for non-emergency situations. Your provider’s office handles most of this behind the scenes, but knowing the process helps if things stall.
A clinical reviewer at the insurance company compares your provider’s documentation against evidence-based guidelines to determine whether the scan is medically necessary. To support the request, your provider needs to submit signed visit notes along with relevant details: your symptoms, physical exam findings, lab results, prior imaging reports, and any treatments that have already been tried and failed. Incomplete or preliminary notes are a common reason for delays, so it’s worth confirming that your provider’s office sent finalized documentation.
If the initial request isn’t approved, the reviewer may schedule a peer-to-peer call, giving your provider a chance to supply additional information. If the scan is still denied, your provider can call to find out exactly what documentation was missing and resubmit. Federal rules are pushing insurers toward faster, more automated decisions, but turnaround times still vary by plan. Asking your provider’s office for a status update after a few business days is reasonable.
What a CT Scan Costs
CT scan prices in the U.S. range widely, from roughly $300 to $6,750 depending on the body part, the facility, and your location. Without insurance, expect to pay around $2,000 or more. With insurance, your out-of-pocket share depends on your deductible, copay, and whether the facility is in-network.
To give a sense of variation by body part:
- Brain CT: averages about $446, ranging from $330 at the cheapest facilities to over $1,000 at the most expensive
- Chest CT: averages about $711, ranging from $400 to nearly $2,800
- Neck CT: averages about $530
- Lumbar spine CT: averages about $540, but can reach $1,900 at high-cost facilities
Freestanding imaging centers tend to charge significantly less than hospital-based radiology departments. If cost is a concern, ask your provider whether the scan can be done at an independent center, and call ahead to get a price quote.
How to Prepare
Most CT scans require little preparation. You won’t need to fast unless your scan involves contrast dye, a solution given through an IV (or sometimes as a drink) that makes certain structures show up more clearly on the images. If contrast is being used, you’ll typically be told to stop eating about two and a half hours before the exam, though clear liquids like water, black coffee, or apple juice are usually fine up to two hours before.
Wear comfortable clothing without metal zippers, snaps, or buttons. Leave jewelry, watches, and piercings at home if possible. You may also be asked to remove eyeglasses, dentures, hearing aids, or hairpins, since metal can interfere with the images.
Before any contrast scan, the technologist will ask whether you’ve ever reacted to contrast dye or have allergies to medications. If you’re pregnant or think you might be, let the team know. Certain patients, including those over 70, those with diabetes, or those with a history of kidney problems, need a blood test to check kidney function within 30 days before receiving contrast. This is because the kidneys filter the dye out of your body, and impaired kidney function (specifically a filtration rate below 30) raises a small risk of kidney injury from the contrast. Your provider’s office usually orders this lab work ahead of time.
What Happens During the Scan
The actual scan is quick and painless. You’ll lie on a narrow table that slides into a large, doughnut-shaped machine. The opening is much wider and shallower than an MRI tube, so claustrophobia is less of an issue. The technologist operates the scanner from an adjacent room and communicates with you through an intercom. You may be asked to hold your breath briefly during certain images to reduce motion blur.
If you’re receiving IV contrast, you’ll feel a warm, flushing sensation that spreads through your body and sometimes a metallic taste in your mouth. Some people briefly feel as though they’ve wet themselves, which is just the warmth, not actual leakage. These sensations pass within a minute or two.
Most CT scans take only 10 to 30 minutes from start to finish, depending on the area being imaged and whether contrast is involved. The scanning itself often lasts just a few minutes; the rest is positioning and preparation.
Radiation Exposure
CT scans use more radiation than standard X-rays, but the doses for routine scans fall in a range that most medical organizations consider acceptable when the scan is clinically needed. A head CT delivers about 2 millisieverts (mSv) of radiation, a chest CT about 7 mSv, and an abdominal CT about 8 mSv. For context, the average person absorbs about 3 mSv per year from natural background sources like radon and cosmic rays.
The risk from a single scan is extremely small for adults. It’s more of a consideration for children, whose smaller bodies absorb proportionally higher doses and whose growing tissues are more sensitive to radiation. Pediatric protocols reduce exposure by adjusting the machine’s power settings based on the child’s size, scanning the smallest area necessary, and using lower-resolution settings when they still provide enough diagnostic detail. If your child needs a CT scan, the imaging center should be using pediatric-specific protocols rather than adult settings.
Getting Your Results
After the scan, a radiologist reviews your images and writes a report interpreting the findings. That report goes to the provider who ordered the scan, who then discusses the results with you. In an emergency setting, preliminary results can come back within minutes. For outpatient scans, expect results within a few days, though many health systems now post radiology reports to online patient portals within 24 to 48 hours. If you haven’t heard anything after a week, call your provider’s office to follow up.