Radiation exposure and mortality risk from CT and PET imaging of patients with malignant lymphoma

OBJECTIVE: To quantify radiation exposure and mortality risk from computed tomography (CT) and positron emission tomography (PET) imaging with (18)F-fluorodeoxyglucose ((18)F-FDG) in patients with malignant lymphoma (Hodgkin’s disease [HD] or non-Hodgkin’s lymphoma [NHL]). METHODS: First, organ doses were assessed for a typical diagnostic work-up in children with HD and adults with NHL. Subsequently, life tables were constructed for assessment of radiation risks, also taking into account the disease-related mortality. RESULTS: In children with HD, cumulative effective dose from medical imaging ranged from 66 mSv (newborn) to 113 mSv (15 years old). In adults with NHL the cumulative effective dose from medical imaging was 97 mSv. Average fractions of radiation-induced deaths for children with HD [without correction for disease-related mortality in brackets] were 0.4% [0.6%] for boys and 0.7% [1.1%] for girls, and for adults with NHL 0.07% [0.28%] for men and 0.09% [0.37%] for women. CONCLUSION: Taking into account the disease-related reduction in life expectancy of patients with malignant lymphoma results in a higher overall mortality but substantial lower incidence of radiation induced deaths. The modest radiation risk that results from imaging with CT and (18)F-FDG PET can be considered as justified, but imaging should be performed with care, especially in children. KEY POINTS: Survival of malignant lymphoma has improved dramatically over the past decades. PET and CT currently play important roles for malignant lymphoma patients. The potential hazard of ionising radiation has become an increasingly important issue. When assessing radiation risks, disease-related reduction in life expectancy should be considered. CT and (18) F-FDG PET create a modest radiation-induced mortality risk.