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Review Article Volume 17 Issue 4
PET tracers: radiation exposure and malignancy risk
Richard C Semelka, Miguel Ramalho
Richard Semelka Consulting, PLLC, USA
Department of Radiology, Hospital da Luz, Portugal
Received: July 27, 2026 | Published: August 10, 2026
Citation: Semelka RC, Ramalho M. PET tracers: radiation exposure and malignancy risk. J Cancer Prev Curr Res. 2026;17(4):122‒126. DOI: 10.15406/jcpcr.2026.17.00619
Abstract
Positron emission tomography/computed tomography exposes patients to two sources of ionizing radiation: internally administered PET radiotracers and externally delivered CT radiation. Although the radiotracer contribution can generally be estimated from administered activity, CT exposure varies substantially according to scan coverage, patient size, equipment, acquisition parameters, and whether the CT is performed for attenuation correction or as a diagnostic-quality examination. This review presents representative effective doses for commonly used PET radiotracers and estimates the associated lifetime attributable risk of malignancy for men and women exposed at age 40 using the Biological Effects of Ionizing Radiation VII model. The CT component may equal or exceed the radiotracer contribution and can substantially increase the total procedural dose. Recent biological evidence demonstrates detectable chromosomal injury following standard-dose PET/CT but not reduced-dose PET/CT, although the absence of a detectable FDG-only effect does not establish the absence of biological injury. Repeated PET/CT examinations may produce substantial cumulative exposure. Current risk models combine event-specific risks but do not provide a validated interval-dependent curve describing how examinations separated by weeks, months, or years interact biologically. Transparent patient counseling should therefore address the total PET/CT exposure, the anticipated CT protocol, the possibility of additional CT examinations, and the cumulative exposure expected from serial imaging.
Keywords: positron emission tomography; computed tomography; radiotracer; effective dose; radiation exposure; lifetime attributable risk; malignancy; repeated imaging
©2026 Semelka, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.