What is a PET Scan?
PET scanning uses a radioactive glucose injection to produce functional images of the tissue within the body. A low dose CT scan is done in tandem with the PET scan and this combination of scans allows diagnosis of diseases at very early stages.Is the radiation dangerous?
Exposure to large amounts of radiation can be harmful to the body e.g. people exposed to large amounts of radiation are more likely to develop some forms of cancer. There is no direct evidence that low exposures to radiation are harmful but it is considered sensible to limit exposures to the lowest amount possible.
Why are precautions advised after PET scans?
All staff involved in the medical exposure of patients are highly trained to ensure the radiation dose delivered as part of the scan is as low as reasonably achievable while ensuring diagnostic quality images are obtained.
It is the duty of Doctors who order scans, and Radiology staff who carry out the scans to ensure that the scans are justified. This means that staff must ensure that when scans are done, the benefits from making the right diagnosis and consequently giving you the right treatment outweigh any small risk involved.
If treatment decisions depend on findings, then the risk to patient’s health from not having the scan is likely to be much greater than that from the radiation itself.
The injected radioactivity can remain in the patient’s body up to 8 hours after injection. It is generally excreted from the body via the kidneys and urine. For this reason certain aftercare and precautions are recommended for the patient and people who come into close contact with the patient ( i.e. people referred to as comforters and carers). The radiographer will inform you on the length of time precautions should be followed.Aftercare for patients:
- Patients should drink plenty of fluids and empty their bladder frequently. When using the toilet they should avoid spills, flush twice and wash their hands thoroughly.
- Nursing mothers should express and discard breast milk for the length of time the radiographer advises and ideally arrange for someone to look after the baby for the rest of the day.
Even though the amount of radiation that comforters and carers might potentially be exposed to is very low, the following precautions are recommended:
- The patient should avoid close contact with pregnant women and young babies for 8 hours.
- Comforters and carers should avoid direct continuous contact with the patient, particularly in the case of a child sitting on your lap watching Television.
- The patient shouldn’t undergo any non urgent investigations and treatments that would involve close staff contact with the patient for periods longer than 30 mins. Such treatments or examinations should be postponed for at least 6 hours post injection.
- The patient should not undergo Blood tests, urine samples and surgery. They should be postponed for 24 hours post injection. Clinical urgency, in exceptional circumstances may dictate otherwise.
- Examination gloves and plastic aprons should be worn when handling urine bags, bottles, bedpans, dirty linen etc.