- Cancer Information
- Cancer treatment
- Radiation therapy
- External beam radiation therapy (EBRT)
- Imaging scans you may have
Imaging scans you may have
During planning and treatment, you may need to have some of the following tests to show the exact position and shape of the cancer. Your treatment team will explain what to expect from each test, or you can call Cancer Council 13 11 20 for more information.
Intense but low-energy radiation passes through the body and creates an image on x-ray film, with darker areas representing soft tissues, and lighter areas showing denser tissues, such as bones.
A CT (computerised tomography) scan uses x-ray beams to create detailed pictures of the inside of the body. Before the scan, you may have an injection of dye into one of your veins to make the pictures clearer. You will lie on a table that moves slowly through the CT scanner.
If you are having radiation therapy for prostate, uterine or cervical cancer, the volume of your bladder will be checked during the scan. This is because the size and shape of the bladder affects the position of the prostate, uterus and cervix. You’ll be asked to drink a set amount of water before treatment to make sure the bladder is full and the prostate, uterus or cervix is in the same position each time.
An MRI (magnetic resonance imaging) scan uses a powerful magnet and radio waves to create detailed cross-sectional pictures of the inside of the body. A dye may be injected into a vein before the scan to make the pictures clearer. You will lie on a table that slides into a large metal tube. The machine can be noisy.
Before a PET (positron emission tomography) scan, you will be injected with a solution containing a small amount of radioactive material. Cancer cells absorb more of the solution and show up brighter on the scan.
This combines a PET scan and a CT scan in one machine. The machine looks similar to a CT scanner.
An ultrasound uses soundwaves to create pictures of your internal organs. A small device called a transducer is passed over an area of the body. The transducer sends out soundwaves that echo when they meet something dense, like an organ or tumour.
Before having scans, tell the doctor if you have any allergies or have had a reaction to dyes during previous scans. You should also let them know if you have diabetes or kidney disease or are pregnant or breastfeeding.
Podcast: Making Treatment Decisions
Download a PDF booklet on this topic.
Prof June Corry, Radiation Oncologist, GenesisCare, St Vincent’s Hospital, VIC; Prof Bryan Burmeister, Senior Radiation Oncologist, GenesisCare Fraser Coast, Hervey Bay Hospital, and The University of Queensland, QLD; Sandra Donaldson, 13 11 20 Consultant, Cancer Council WA; Jane Freeman, Accredited Practising Dietitian (Cancer specialist), Canutrition, NSW; Sinead Hanley, Consumer; David Jolly, Senior Medical Physicist, Icon Cancer Centre Richmond, VIC; Christine Kitto, Consumer; A/Prof Grace Kong, Nuclear Medicine Physician, Peter MacCallum Cancer Centre, VIC; A/Prof Sasha Senthi, Radiation Oncologist, The Alfred Hospital and Monash University, VIC; John Spurr, Consumer; Chris Twyford, Clinical Nurse Consultant, Radiation Oncology, Cancer Rapid Assessment Unit and Outpatients, Canberra Hospital, ACT; Gabrielle Vigar, Nurse Unit Manager, Radiation Oncology/Cancer Outpatients, Cancer Program, Royal Adelaide Hospital, SA.
View the Cancer Council NSW editorial policy.
Coping with cancer?
Ask a health professional or someone who’s been there, or find a support group or forum
Looking for transport, accommodation or home help?
Practical advice and support during and after treatment