Safety Concerns with PET/CT Imaging

THERE IS ONLY 1 IMAGE. PLEASE PUT IT ON THE RIGHT SIDE, AS THOUGH IT WAS A CASE TO OPEN. BUT MAKE IT PERMANENTLY OPEN, SO THAT IT DOES NOT HAVE TO BE CLICKED ON TO OPEN

Radiation Exposure to the Patient:

Because each scan includes both a full body CT scan and radiation exposure from the injected radionuclide, a PET/CT scan exposes the patient to significant radiation  — even when imaging parameters are modified to decrease exposure “as low as reasonably achievable” (ALARA).

Calculated radiation dosages vary greatly, depending on the CT imaging protocol, the part of the body imaged, the size of the patient and the amount of radiotracer injected.

• Average dose of the CT exam: 800-2500 mRem
• Average dose from the PET exam: 600-900 mRem

• Total Exposure from one PET/CT scan: 1400-3300 mRem

To put this in perspective, radiation exposure from a routine P.A. Chest radiograph is about 2 mRem. So just one PET/CT scan can easily result in a larger radiation dose than 1,000 chest radiographs.

As with all medical procedures and exams, the decision to obtain a PET/CT scan is based on a risk/benefit analysis.

It has been estimated that the lifetime attributable risk of cancer (LAR) from one PET/CT scan may be as high as 0.5% (depending on the imaging protocol, patient size and patient age/gender).

Radiation Exposure to the Patient’s Contacts:

Although the patient will leave the exam with radiotracer in his body, there is no appreciable risk to those who come into close contact with the patient after the exam — excluding medical staff who are exposed to multiple patients every day (International Atomic Energy Commission).

• Contact with Children & Pregnant Women: The IAEA states that close contact with children and pregnant women should be kept “as short as possible” (8 hours of separation is a common recommendation).
• Breast Milk: As 18F-FDG is excreted into breast milk, breastfeeding mothers are usually advised to express and discard their milk for a short while after their exam. Although the IAEA suggests that breast milk is safe just 2 hours after the exam (this first 2-hour milk is expressed and discarded), most centers still recommend waiting 24-hours before resuming breastfeeding.