During Treatment

We advise you keep a strong working relationship with your clinical support team. You should have all your questions answered by your team. We have some resources below that you may find of value.

10282669097?profile=RESIZE_584xWhat is PET CT?

A PET (Positron Emission Tomography) scan is a diagnostic imaging tool that produces pictures of any abnormal cell activity in the body.  This can occur before changes may be visible on conventional imaging. A tiny amount of a radioactive substance, called a radionuclide (radiopharmaceutical or radioactive tracer), is used during the procedure. This assists in the examination of the tissue under study.

PET scans can detect cancers, brain disorders such as Alzheimer’s Disease, Parkinson’s Disease and epilepsy, heart disease and bone abnormalities.

CT (Computed Tomography) uses a combination of x-rays and high-powered computers to obtain cross-sectional images of the body.

The combination of PET and CT produces a highly sensitive imaging device able to detect early stages of disease often undetectable by CT alone or by other imaging procedures such as MRI.

PET CT scans are simple and painless. They offer patients and their families information that helps doctors detect and diagnose disease early. This means the patient can  begin treatment quickly. It can also provide much more specific information. It can distinguish between benign and malignant disorders for example. This is unlike other medical imaging techniques such as ultrasound, x-rays, MRI or CT that merely confirm the presence of a mass.

PET CT can also help doctors monitor the treatment of disease. For example, chemotherapy leads to changes in cellular activity and these changes can be seen on PET CT scans. This can be long before any structural changes can be measured by other imaging techniques. These scans give doctors another tool to evaluate treatments, perhaps even leading to a modification in treatment before any other imaging is done. Note that PETCTs have a high radiation output relative to CT scans and are to be used selectively, particularly in younger patients

PET CT scans for public patients

-           PET scans are given as a standard workup to stage many HNC’s (such as occult primary, nasopharynx, oropharynx). They are used to  assess response after treatment for many of these same tumours (those treated with RT or CRT without surgery).

-          non-SCC HNC’s (melanoma, sarcoma, some adenoca)


-           selectively for some patients who appear to have high tumour burden (Stage 4) to ensure there are not other areas of disease prior to planning treatment.

-          patients with recurrent disease after primary treatment

PET scans are used for patients who have had their oropharyngeal tumours treated primarily with surgery. This allows the clinicians to compare like with like for any audit purposes. 

PETCT is DHB funded for the regionally recognised indications. There is variation as to what is recognised in different parts of the country. This is likely to change as a result of the health reforms currently in progress. Access is variable with regards needing to travel - some parts of the South Island are a long way from Christchurch.

If an indication falls outside what is funded then there is a process for those patients to be assessed on a case by case basis by members of our variance committee.  The committee also meets twice a year to review data and determine recommendations for new indications or variations on the existing ones. Clinicians can request consideration for PET CT outside of these where there is good evidence to support the application on case by case.

The Northern Region PET Advisory Committee meets 6 monthly to consider new international evidence for PET scans as appropriate.

It is believed that private PET Scans  follow the national indications framework as well.



Diana Ayling