Lifetime attributable risk of radiation exposure from cardiac and parathyroid SPECT/CT scan

Abstract

Introduction

Single-photon emission computed tomography (SPECT) and computed tomography (CT) cardiac and parathyroid examinations play crucial roles in diagnosing and managing cardiovascular and endocrine disorders. However, concerns exist regarding the patient radiation exposure associated with their use. This study aimed to assess the risk of developing cancer from cardiac and parathyroid SPECT/CT examinations by estimating cancer risk in patients who underwent these procedures.

Methods

Data were collected from patients who underwent cardiac or parathyroid scans at a hospital in Madinah, Saudi Arabia. The lifetime attributable risk (LAR) was calculated using the United States National Research Council Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation VII approach. The absorbed doses from the SPECT and CT scans were calculated using the National Cancer Institute software.

Results

Seventy patients underwent cardiac and parathyroid SPECT/CT examinations. For cardiac SPECT/CT scans, cancer risk was generally minimal. However, in males under 50, ^99mTc-MIBI Sestamibi contributed to a significant colon cancer risk (12 cases per 100,000 people). In parathyroid examinations, the risk was notably higher. For males, colon cancer risk was substantial (24 cases per 100,000 people), while females faced increased risks of lung (29 cases per 100,000 people) and breast cancer (16 cases per 100,000 people). Both radiopharmaceuticals and CT scans contributed to the higher cancer risks associated with parathyroid examinations than cardiac SPECT/CT scans.

Conclusion

The cancer risk associated with cardiac and parathyroid SPECT/CT examinations was relatively low. These findings can contribute to optimizing imaging protocols, radiation dose reduction strategies, and patient counseling regarding the benefits and risks of these imaging procedures.