There are many different types of imaging or scans, and they all give your oncologist a way to see what is going on inside of your body. The type of imaging/scan used will depend on what type of information is needed by your provider. 

How is imaging used? 

Imaging is utilized in cancer care for many reasons. Early on, it is likely used to better view and locate your cancer, to determine its stage, and to help decide the best course of treatment. Later it may be used to evaluate how effective treatment was and to monitor for any recurrence or progression of cancer. Imaging can also assist physicians in determining if a biopsy needs to be done and what area to biopsy.  

Common types of imaging and what to expect 

Computed tomography (CT) scan:  

A CT scan uses precise x-rays controlled by a computer to create three-dimensional images of the body. With this type of imaging, it is possible to view bones, soft tissue, organs, and blood vessels. It can show whether a tumor is present as well as its location. CT scans can also be used to perform needle biopsies of tumors and radiofrequency ablation (RFA) to help destroy tumors. 

What to expect: 

• You may be given contrast that will provide a clearer picture defining the boundaries of organs and tumors. The contrast may be something you have to drink, it may be given through an IV, or it could be both.  

• You may be asked to undress partially or fully and given a gown to wear for the scan.  

• You’ll be asked to remove items such as jewelry, hair accessories, piercings, underwire bra, or any other metal objects.  

• You’ll lie flat on a table and slide through a scanner which is shaped like a large doughnut. You may hear humming, buzzing, or clicking as the images are obtained. 

• CT scans on average take between 15 and 45 minutes depending on the body parts being scanned. However, if oral contrast is ordered, it will need to be taken 60 to 90 minutes prior to the scan.  

Possible complications or side effects:  

• There is a risk of reaction to the contrast. It’s important to let your doctor know if you’ve ever had a reaction to contrast dye, or if you have an allergy to shellfish or iodine. Symptoms of a reaction may include rash, nausea, shortness of breath, wheezing, itching, or facial swelling. 

• The IV contrast can be tough on your kidneys, so if you have any history of kidney problems your doctor will want to check your kidney function with a blood test before the CT scan. Depending on the results, you may get IV fluids to help flush the dye through your kidneys. 

Magnetic resonance imaging (MRI):  

An MRI uses strong magnets to capture three-dimensional images like a CT scan. However, an MRI can provide clearer images of soft tissues. An MRI can be used in identifying cancers found in soft tissue, like prostate, uterine, and some liver cancers. An MRI is also a better option to see if there has been any metastasis to the brain. 

What to expect:  

• You may be asked to undress fully or partially and placed in a gown.  

• Because of the strong magnetic field, you will be required to remove any metal objects, such as jewelry, piercings, or hair accessories that will be affected by the magnet.   

• Prior to your MRI, the technician will ask about any implanted metal such as a pacemaker, surgical clips, screws, artificial joints, or tattoos so that any needed precautions can be taken. 

• You will lie on a flat, narrow table that will slide you into a tube-like machine.  

• Your provider may request the MRI with or without Gadolinium contrast.* If contrast is ordered, it may be something you have to drink, or it may be given through an IV. This is a different IV contrast than used in CT scans, but be sure to let your provider know if you have ever had issues in the past with contrast. 

• On average, you can plan on an MRI scan lasting between 45 to 60 minutes but, depending on what images are ordered, it could take up to two hours.  

Potential complications or side effects: 

• It can be unsettling to be in a confined space for the time that it takes to complete an MRI; some people become very anxious or may even panic. Make sure to discuss these concerns with your provider. 

• There is a risk of having a reaction to the contrast. Symptoms of a reaction could include nausea, headache, feeling dizzy or lightheaded, or pain at the injection site.  

• The contrast can also cause issues for patients on dialysis or with severe kidney issues. Patients with this risk are often not given the contrast.

Positron emission tomography (PET) scan:  

A PET scan is like a CT scan, but instead of using contrast to show detailed images of tissue and organs, a PET scan uses an exceptionally low dose radioactive tracer (radionuclide, specifically a radioactive sugar) that will indicate where abnormal activity is occurring in the body. Since cancer cells use more energy than healthy cells, they will absorb radioactive sugar and can be more sensitive than other imaging scans. PET scans can show where cancer cells are located, help to stage the cancer, help to determine the best location for biopsy, and help to gauge the effectiveness of treatment.  

What to expect:  

Instructions to prepare for a PET scan will vary depending on what part of your body is being scanned.  

• You may be instructed not to eat or drink anything for a specific time before the scan, or you may be required to eat a low carbohydrate diet 24 hours prior to your scan to avoid spikes in glucose which could affect the scans. Your provider will give you the correct instructions. 

• The tracer will be given intravenously which means you will need an IV.  

• You will sit for 30 to 90 minutes to allow it to reach the appropriate area of the body. Typically, the PET scan itself will last around 30 minutes. 

• The scanner looks like a large doughnut, and you will hear whirring and clicking sounds as it captures the images. You will be positioned on a flat table that will slide you back and forth through the scanner.  

• After your PET scan you can return to your normal activities. It is beneficial to make sure to drink plenty of water for the next few days to help flush the tracer out of your body. 

Potential complications or side effects:  

• Occasionally there may be swelling or pain where the tracer is injected, but the doses of radiation are small, and the radionuclides tend to have an exceptionally minimal risk of allergic reaction. 

Special considerations:  

• The amount of radiation associated with the tracers used for these scans is low and will naturally break down in your body over time. However, it is important to know that the radiation may also leave your body through urine and stool over a matter of hours or days. Be sure to talk with your provider about exposure and precautions to take regarding sex and being around pregnant women and children. 

Bone scan 

This scan is used to look for cancer that has started in or metastasized to the bone. 

What to expect:  

• A radioactive tracer like the one used in a PET scan will be given into your vein through an IV.  

• You’ll typically wait one to four hours for the tracer to travel to your bones. The scan itself typically takes one hour to complete. 

• Before the scan you’ll be asked to undress partially or fully and put on a gown, as well as remove any jewelry or metal objects that may interfere with the scan.  

• You’ll lie on an exam table while the scanner slowly moves along your body. It’s important to stay as still as possible to ensure clear images.  

• After your bone scan it is beneficial to continue to drink plenty of water for the next couple of days to help flush the rest of the tracer out of your body. 

• You are not considered radioactive or posing any risk to others. The amount of radiation from the tracer is less than that of a normal x-ray. 

Potential complications or side effects:  

• The potential complications or side effects for a bone scan are the same as those for a PET scan. 

*Gadiolinum and IV iodine contrast can impair kidney function. Your doctor may order blood work to check your kidneys before you receive IV contrast.