Radiation protection issues in dynamic contrast-enhanced (perfusion) computed tomography.

Area of Science:

• Radiology and Medical Imaging
• Radiation Protection
• Medical Physics

Background:

• Dynamic contrast-enhanced computed tomography (DCE-CT) is increasingly utilized in clinical practice and research for diagnosing critical conditions like stroke, coronary artery disease, and cancer.
• Patient safety is paramount, necessitating a thorough understanding of radiation effects associated with advanced imaging techniques.

Purpose of the Study:

• To review deterministic and stochastic radiation effects relevant to patient protection in DCE-CT.
• To present methods for determining radiation doses and risks in DCE-CT studies.
• To discuss justification and optimization strategies for DCE-CT protocols.

Main Methods:

• Absorbed doses were measured using thermoluminescent dosimeters in an anthropomorphic phantom for three DCE-CT protocols (cerebral, myocardial, cancer perfusion).
• Life-time attributable cancer risks (LAR) were estimated using sex-, age-, and organ-specific models based on a linear non-threshold dose-response relationship.

Main Results:

• Local absorbed doses for brain, heart, and pelvic cancer DCE-CT protocols ranged from 15-270 mGy.
• Estimated LARs for cerebral and myocardial DCE-CT at age 40 were below 0.1%, significantly lower than for pelvic cancer studies.
• Radiation risks were found to be age-dependent and higher in females than males.

Conclusions:

• DCE-CT imaging involves radiation doses that require careful consideration for patient protection.
• Harmful tissue reactions are generally associated with doses above 0.5 Gy, with stochastic risks being lower but present.
• Strict justification and optimization of DCE-CT studies are essential to balance diagnostic benefits with radiation safety.