Low-Dose CT

Computed tomography (CT) is an imaging test used to create images of internal organs, bones, soft tissue and blood vessels. The images generated during a CT scan are used to generate three-dimensional images and are often the best method for detecting different cancers.

A Computed Tomography (CT) scan is a painless procedure used to obtain cross-sectional “sliced” images of the body. The scan combines a series of X-ray views taken from many different angles and computer processing to create cross-sectional images of the bones and soft tissues inside your body. The images are then viewed on a monitor.

A CT scan can be used for most parts of the body. It is a useful tool for isolating the location of a tumor, infection or blood clot and can detect internal injuries and internal bleeding. A CT can also detect and monitor diseases and conditions, including lung nodules, liver masses, cancer and heart disease.

Depending on your physician’s request, you may receive a “contrast” material by mouth and/or IV. This “contrast” does exactly as it says: it helps provide greater contrast and information so we can better read the image. During the scan, you will lie down on a CT table. The table moves through the CT scanner opening while obtaining images. The CT procedure can take from 15 to 45 minutes.

Unless otherwise indicated, do not eat or drink anything but water four hours prior to your study. We encourage drinking water prior to your exam. Some patients may be asked to drink oral contrast before their study, which enhances the images. Typically, we ask patients to arrive one hour in advance to drink oral contrast; however some patients may receive oral contrast in advance with instructions specific to their study. In some cases, no oral contrast may be necessary.

  • If drinking contrast, please arrive one hour and 30 minutes prior to your exam time.
  • If your study does not require contrast, please arrive 30 minutes prior to your exam.

Some studies require different preparations. Please be sure to review the details for your particular study.


Please notify our scheduling department and technologists if:

  • You are pregnant
  • You have severe allergies, or if you have ever had an allergic reaction to X-ray dye or iodine.
  • You have any medical conditions such as asthma or diabetes.
  • You have a history of renal failure, liver or kidney transplant.
  • You are diabetic. Diabetic patients should discontinue use of Metformin containing drugs the day of the exam and 48 hours after the procedure.
Prep Forms

A highly specialized radiologist will interpret your images and prepare a diagnostic report for your physician. If the examination was ordered “stat” your physician will be notified the same day. If the examination was routine, the results are provided to your physician within 48 hours. Your physician will determine how the radiologists’ report can be used to develop a treatment plan and speak with you about your results.

Q. What are the risks of a CT?

A. This procedure is extremely safe, though it does use radiation to produce the images. At Oregon Imaging Centers, we use the least amount of radiation by utilizing a “low dose” technology which decreases the radiation exposure .

Q. Why did my doctor order a CT if radiation is a concern?

A. CT is a valuable diagnostic tool that uses radiation to peer into the body and produce 3-D images. Based on your symptoms or the area being scanned, a CT scan will provide your doctor with the most detailed information.

Q. What steps do you take to reduce radiation?

A. We adhere to the As Low As Reasonably Achievable (ALARA) principle, using tools that automatically adjust the radiation dosage based on body type and anatomy. As part of that commitment, we invested in technology that uses software to reduce radiation exposure. The amount of radiation you receive varies by body type and the anatomic region being scanned.

Q. Is there an IV involved with the CT?

A. Depending on your physician’s request, you may receive an “intravenous contrast,” which is needed for many exams.

Q . How should I prepare for my CT?

A. You will receive instructions when you schedule your appointment. You can also refer to the “prep” section of the website. Be sure to review the instructions for your particular study, as they can vary based on type of study.


What: An abdominal CT is a non-invasive way for your doctor to evaluate your internal organs and tissues including the liver, spleen, pancreas and kidneys. The test can help diagnose abdominal pain. Some of the more common reasons for an abdominal CT scan are for the evaluation of tumors, infections, kidney stones or appendicitis.


What: CT angiography is used to examine blood vessels.

Physicians may use the procedure to:

  • Identify disease and aneurysms in the aorta or in other major blood vessels.
  • Guide surgeons making repairs to diseased blood vessels, such as implanting or evaluating a stent.
  • Identify dissection in the aorta or its major branches.
  • Screen individuals for arterial disease, especially patients with a family history of arterial disease or disorders.
  • Detect thrombosis (clots) in veins.

The images captured in this scan allow the radiologist to construct a three-dimensional image of your heart and measure blood flow, as well as narrowing of the arteries.

This study will require IV injected contrast agents to help us visualize certain tissue or blood vessels. Some patients describe a metallic taste or tingling sensation right after the injection. This is normal and usually subsides very quickly.

Calcium Scoring

What: Calcium screening is most appropriate for men, ages 35 to 70 and women 40 to 70 who have any of these risk factors: family history of heart disease, smoking, diabetes, high cholesterol, high blood pressure or overweight. CT calcium scoring requires an order from your licensed primary or specialty provider. Medicare members require an order from a provider other than a chiropractor or naturopath.

This test allows the radiologist to determine if calcium build-up, or plaque, is present on the walls of the arteries of the heart, also known as your coronary arteries. The radiologist will report to your physician on how severe the blockages are.

No prep is required for this study; you may eat and drink before the procedure.

Cardiac Angiogram

What: Cardiac CT Angiography is used to examine blood vessels in and around the heart.

Physicians may use the procedure to:

  • Guide surgeons making repairs to diseased blood vessels, such as implanting or evaluating a stent.
  • Show the extent and severity of atherosclerosis in the coronary arteries.
  • Plan for a surgical operation, such as coronary bypass.
  • Screen individuals for arterial disease, especially patients with a family history of arterial disease or disorders.

Your doctor will be ordering a beta blocker for you to take the morning of the exam. This is to slow your heart rate down.

The images captured in this scan allow the radiologist to construct a three-dimensional image of your heart and measure blood flow, as well as narrowing of the arteries.

This study will require IV injected contrast agents to help us visualize certain tissue or blood vessels. Some patients describe a metallic taste or tingling sensation right after the injection. This is normal and usually subsides very quickly.

In addition to the general CT prep guidelines, please refrain from consuming caffeine in any form 12 hours prior to exam.


What: A CT scan of the chest may be ordered by your physician when there is a chest injury or if a tumor is suspected. It can also help determine the size, shape and position of internal organs and help your doctor look for bleeding or fluid in the lungs. A chest scan can find abnormalities in the aorta and disease or damage to the heart.

Head & Neck

What: A CT scan of the head can provide valuable information about head injuries, tumors, stroke or diseases of the brain. The test can also help evaluate conditions of the eyes and sinuses.


What: A CT KUB makes it possible to evaluate the kidneys, ureter and bladder. Since CT scans can distinguish between solid and liquid, it is extremely valuable in examining the type and extent of kidney tumors or other masses, such as stones or cysts, distorting the urinary tract. You do not need to fast or avoid liquids before this study.

Lung Screening

A CT scan of the lungs is often ordered when your physician is trying to determine if there is bleeding or fluid in the lungs. It may also be ordered if a tumor is suspected or to determine the size, shape and position of a known tumor.

Why it’s worth your time: Lung cancer is the third most common cancer and the leading cause of cancer deaths in the US. However, early detection is now possible with CT technology and it is often covered by insurance. If cancer is detected early, it is very likely your outcome will be better and treatment will be less invasive.

Cancer of the lung and bronchus account for more deaths than colon, breast and prostate cancer combined. Various well understood factors contribute to lung cancer, and they are used as the criteria for insurance coverage of the CT lung screening.

The criteria: Most insurance providers are using this criteria to determine coverage:

  • 50-80 years of age.
  • Current smoker who smoked on average at least one pack of cigarettes per day for 20 years or more.
  • Former smoker who quit less than 15 years ago, after a significant smoking history.
  • Currently without symptoms of lung cancer.

How screening works: The screening is done using a CT, which uses X-ray technology to get detailed images of the body. The newest CT machines – like those Oregon Imaging uses – expose you to very little radiation because they very quickly take a succession of detailed shots that build a clear picture for a radiologist to interpret.

The radiologist will analyze the scan to identify any spots, which may or may not indicate cancer. If a spot(s) is detected, you’ll be asked to return in six months to look for any changes in size. Lung cancer typically develops slowly and this allows for monitoring without the invasiveness of a biopsy. If there has been a change to the spot, your physician will make a recommendation on next steps for monitoring or further study.

What to expect: The imaging is simple and you will not experience discomfort. You will be asked to change into a gown. You will rest on your back on a table that passes through a circular opening in the CT imaging system. It takes just a couple of minutes.

Insurance coverage: Most insurance plans, including Medicare, are in the process of implementing coverage for lung screenings for those who meet the below criteria. For many plans, the benefits provide for full coverage with no patient financial responsibility. Some plans require the lung screenings to be prior authorized for benefits to apply. Please contact your health plan for the specific information about your lung screening benefits.

Next steps: Check with your provider to determine whether your screening is covered and if you need pre-authorization. Then call us to schedule an appointment, or request an appointment online.


What: CT of the sinuses primarily is used to:

  • Detect the presence of inflammatory diseases.
  • Plan for surgery by defining anatomy or giving further information about tumors of the nasal cavity and sinuses.
  • Evaluate sinuses that are filled with fluid or thickened sinus membranes.
  • Help diagnose sinusitis.


What: The most frequent use of spinal CT is to detect — or rule out — spinal column damage in patients who have been injured.

In patients with narrowing of the spinal canal, vertebral fracture, infection or degenerative disease such as arthritis, CT of the spine may provide important information when performed alone or in addition to magnetic resonance imaging (MRI). CT scanning of the spine is also performed to:

  • Evaluate the spine before and after surgery.
  • Detect various types of tumors in the vertebral column, including those that have spread from another area of the body. Some tumors that can arise elsewhere are first identified by finding deposits of malignant cells in the vertebrae; prostate cancer is an example.
  • Help diagnose spinal pain, such as a herniated intervertebral disk.
  • Accurately measure bone density in the spine and predict whether vertebral fractures are likely to occur in patients at risk of osteoporosis.

Virtual Colonoscopy

What: The major reason for performing CT colonography is to screen for polyps and other lesions in the large intestine. Polyps are benign growths that arise from the inner lining of the intestine. Some polyps may grow and turn into cancers.

The goal of screening with colonography is to find these growths in their early stages, so that they can be removed before cancer has had a chance to develop. Most physicians agree that everyone older than 50 years should be screened for polyps every seven to 10 years. Individuals at increased risk should be screened every five years. Risk factors for the disease include a history of polyps, a family history of colon cancer, or the presence of blood in the stool.

How it works: Using a CT scanner’s X-rays we will take cross-sectional images of your abdominal cavity and colon. These images will be assembled by a computer into a three-dimensional rendering allowing the radiologist to ‘fly-through’ or virtually examine the colon. During the study, a small enema tip is inserted into the rectum and air is used to inflate the colon.