Review finds PET imaging safe and clinically valuable in pregnant women with breast cancer

A new review from UCLH and the Whittington Health NHS Trust has shown that a standard imaging tool used in cancer can be safely used in selected pregnant women with breast cancer, offering crucial information to guide treatment decisions without compromising foetal safety.

FDG-PET (fluorodeoxyglucose positron emission tomography) is used to detect cancer spread and guide therapy. However, its use in pregnancy-associated breast cancer (PABC) has remained controversial due to concerns around foetal radiation exposure.

In this UK-first case series, published in the June 2025 edition of Nuclear Medicine Communications, researchers reviewed the outcomes of six pregnant patients with high-risk breast cancer who underwent PET imaging using adapted ultra-low-dose protocols. The review found that the estimated radiation dose to the foetus was significantly below internationally accepted safety thresholds, with no immediate adverse effects reported in any of the infants.

The imaging also changed assessment of cancer stage and management in one-third of cases.

The analysis was led by Dr Karen DeSouza, Consultant Medical Oncologist, and Dr Stefan Vöö, Consultant Nuclear Medicine Physician, who both work across UCLH and Whittington Health.

Dr DeSouza said:

“For carefully selected patients, PET imaging can provide vital staging information that directly influences treatment, including the timing of surgery and administration of chemotherapy. In this small series, we saw no short-term harm to the foetus and meaningful clinical benefit to the mother. These findings offer much-needed reassurance to both clinicians and patients navigating cancer care during pregnancy.”

Dr Vöö said:

“By significantly reducing the dose and using optimised imaging protocols, we were able to keep foetal radiation exposure well below levels associated with any known risk. These results show that PET imaging, when used judiciously, can be both safe and clinically impactful during pregnancy.”

The authors call for further, larger studies to confirm long-term safety and help shape national guidelines.

UCLH and Whittington Health have a long history of working together, particularly on clinical pathways. This work is an example of how our two organisations are also collaborating on research studies and reviews, based on a close and trusted relationship.