Pregnant Women and Radiation

Special Considerations

Pregnant women require special consideration when exposed to ionizing radiation, as there is a higher probability of inducing radiation effects in the unborn child compared to adults. As a general rule, diagnostic and therapeutic nuclear medicine procedures should be avoided in women likely to be pregnant, unless there are strong clinical indications for the procedure.

Evaluation for Pregnancy

To prevent unintentional irradiation of the unborn child, a woman of childbearing age should be evaluated for pregnancy or a missed period prior to the examination or treatment. This evaluation is typically done during the interview and information-giving phase before the procedure. It is common practice to display a poster in the waiting area asking women to notify staff if they are or think they may be pregnant.

Procedure with Confirmed Pregnancy

If a woman is confirmed not to be pregnant, the examination or treatment can proceed as planned. However, if pregnancy is confirmed, careful consideration should be given to:

• Exploring alternative diagnostic methods or postponing the procedure until after delivery.
• If no alternatives are available or feasible, the procedure should proceed with careful optimization of protection for the embryo/fetus.

In such cases, efforts should be made to reduce fetal exposure by:

• Reducing the administered activity and acquiring images over a longer duration, ensuring not to compromise the quality of the results.
• Encouraging frequent voiding to minimize exposure from the bladder.
• Administering the radiopharmaceutical when the bladder is partially filled to further reduce exposure.

CT in PET/CT or SPECT/CT Examinations

A particular concern is the use of CT in PET/CT or SPECT/CT examinations. Routine diagnostic CT of the pelvic region, with or without contrast, can lead to a dose of 50 mSv to the uterus, which is considered to be equivalent to the fetal dose during early pregnancy. Therefore, it is important to:

• Use low-dose CT protocols.
• Minimize the scanning area during PET/CT or SPECT/CT scans for pregnant patients.

Radionuclide Therapy and Pregnancy

Pregnant women should not undergo therapy with radioactive substances unless the treatment is life-saving. After a therapeutic radionuclide application, women should be advised to avoid pregnancy for an appropriate period.

Fetal Dose Considerations

If the fetal dose is estimated to exceed 10 mSv, it should be carefully assessed by a qualified medical physicist, and the pregnant woman should be informed of the potential risks. The same procedure applies in the event of an inadvertent exposure (e.g., if a woman later discovers she was pregnant at the time of exposure or during an emergency situation).

Radiation Exposure and Pregnancy Termination

Exposure of a pregnant patient when the pregnancy was not known may cause concern about the possible effects on the fetus. This can lead to discussions about the potential termination of pregnancy due to radiation risks. However, it is generally considered that for fetal doses under 100 mGy (as typically encountered in most diagnostic procedures), termination is not justified from a radiation perspective.

For higher doses, individual circumstances should be carefully considered. This is an ethical issue and should be addressed based on national guidelines.

Note: Many misunderstandings have led to unnecessary termination of pregnancies, which could have been avoided with accurate risk assessments.

Important: Always consult with a qualified medical physicist and follow national guidance when managing radiation exposure in pregnant women.