What is PET-CT?
Positron emission tomography, also called a PET scan, is a nuclear medicine exam that produces a three dimensional image of functional processes in the body. It provides and combines comprehensive information on the abnormal activity and function of cells (obtained by PET) as well as the precise location of these abnormalities in the body (obtained by CT) into one machine. A PET/CT scan reveals information about both the structure and function of cells and tissues in the body during a single imaging session.
During a PET/CT scan, the patient is first injected with a glucose (sugar) solution that contains a very small amount of radioactive material. The substance is absorbed by the particular organs or tissues being examined. The patient rests on a table and slides into a large tunnel-shaped scanner. The PET/CT scanner is then able to “see” damaged or cancerous cells where the glucose is being taken up (cancer cells often use more glucose than normal cells) and the rate at which the tumor is using the glucose (which may help determine the tumor grade). The procedure is painless and varies in length, depending on the part of the body that is being evaluated.
By combining information about the body’s anatomy and metabolic function, a PET/CT scan provides a more detailed picture of cancerous tissues than either test does alone. The images are captured in a single scan, which provides a high level of accuracy.
What are the benefits of PET-CT?
PET-CT is especially useful in the field of oncology or cancer management, where it enables :
Detection of smaller lesions; enabling earlier detection of cancers & improved staging of known cancers
Detection of spread of tumors in the body
Effects of treatment of cancers can be better evaluated at an earlier stage
Follow-up to exclude recurrence of cancer
Improve cure rates as well as patient survival & to reduce the overall cost of treatment
More accurate treatment planning for radiotherapy with reduction in radiation dose to normal tissue
PET/CT PATIENT PREPARATION
1. Patient safety prior to PET/CT exam.
- Please let us know if you have any allergies or adverse reactions to medications.
- If you are pregnant or may be pregnant, or breastfeeding/ nursing mother, please tell your Doctor or Nurse.
- Please leave your valuables at home or in your room in the hospital.
- Please let us now if you need interpreting services, this can be arranged for you. Bring a list of your current medications with you as well as you diabetic medicine during your PET/CT appointment.
- Please bring your previous scan and reports, biopsy and blood results.
- Pregnant women and child under 12 years old are not allowed to accompany you during your PET/CT appointment.
2. Preparation for PET/CT procedure
- In order to avoid delay and cancellation of PET/CT scan, patient with diabetes must have plasma glucose control between 4 – 11 mmol/L to achieve optimum quality of scan.
- You must avoid any strenuous exercise and deep tissue massage for 48 hours before your PET/CT appointment.
- You will be asked to follow the Limited Carbohydrate diet for the previous 24 hours before the date of your appointment.
- Do not eat or drink anything, except plain water, for 6-8 hours before the exam. If you appointment is before 11.30 a.m., you can start fasting from midnight, but if your PET/CT appointment is after 11.30 a.m. you can start fasting from 6.00 a.m.
- You may drink plain water, as much water as you can. Consumption of 1 litre of water during the 2 hours period prior to injection is suggested.
- Routine medications may be taken, unless you have been instructed otherwise. If you are diabetic, you may take your diabetes medication no less than 4 hours prior to the exam.
- As metformin increases the uptake of glucose in the gut and will interfere with the quality of the scan, metformin or combination drugs containing metformin will need to be stopped for 48h before scan.
- Referring clinicians may need switch to other oral hypoglycaemic agents temporarily and to advise patients to do a trial run of 48 hours at least 2 weeks in advance without metformin to test out their blood sugar level, so as to allow ample time to switch to other oral hypoglycaemic agents should it be required.
- Arrive 30 minutes before your PET/CT scan for registration and screening.
- The NM Nurse or NM Radiographer will verify your identification and exam requested.
3. During PET/CT Scan
- The duration of the exam will vary, but the average is about 2-3 hours.
- The Radiographer will position you on the PET/CT table, and give you instructions to remain still.
- You will have the opportunity to ask the radiographer questions.
4. After Procedure
- You should drink about 5 glasses of water and pass urine regularly.
- If you are breastfeeding mothers, you should wait for 24 hours before resuming breastfeeding.
- If you feel any symptoms such as nasal congestion, itchy eyes, hives, rashes, sneezing, restlessness, tremors, pain, nausea, vomiting, dizziness, please notify the staff immediately. The staff is prepared to handle these situations. If you feel any of these symptoms after you have left the department, please contact your doctor or go to the nearest hospital.