What is the radiation exposure to a patient from a lower extremity angiogram (leg angiogram)?

From the Guidelines

A normal leg angiogram typically exposes a patient to approximately 5-10 millisieverts (mSv) of radiation, though this can vary based on several factors. The exact dose depends on the complexity of the procedure, patient size, equipment used, and imaging protocols implemented by the facility. For context, this radiation exposure is roughly equivalent to 2-3 years of natural background radiation that we receive from our environment. The radiation comes from the X-ray imaging required to visualize the blood vessels after contrast dye is injected. Modern angiography equipment often uses dose reduction techniques to minimize exposure while maintaining image quality, as highlighted in the 2018 ACC/HRS/NASCI/SCAI/SCCT expert consensus document on optimal use of ionizing radiation in cardiovascular imaging 1.

While this level of radiation carries a small theoretical risk, the diagnostic benefits of identifying vascular problems typically outweigh these risks for patients with suspected peripheral artery disease or other vascular conditions requiring this examination. It is essential to consider the risk-benefit relationship of the procedure, as stated in the 2018 ACC/HRS/NASCI/SCAI/SCCT expert consensus document 1, and to apply appropriate use criteria to select patients for diagnostic and therapeutic procedures, as recommended in the 2018 ACC/HRS/NASCI/SCAI/SCCT expert consensus document on optimal use of ionizing radiation in cardiovascular imaging, part 2 1.

Some key factors to consider when evaluating the risks and benefits of a leg angiogram include:

• Patient age and life expectancy
• Presence of comorbidities
• Complexity of the procedure
• Equipment used and imaging protocols implemented
• Potential for radiation-induced cancer, which is generally very small in absolute terms, as noted in the 2018 ACC/HRS/NASCI/SCAI/SCCT expert consensus document 1. Patients should not need any special precautions after the procedure related to the radiation exposure itself. However, it is crucial to minimize patient radiation exposure, especially in younger patients with long natural life expectancies, and to consider alternative modalities that do not involve radiation exposure, as discussed in the ACR Appropriateness Criteria for sudden onset of cold, painful leg 1.

From the Research

Radiation Exposure in Leg Angiogram

• The amount of radiation exposure during a leg angiogram can vary depending on several factors, including the patient's physical characteristics, the procedure preferences of the radiologist, and the difficulties encountered during the procedure 2.
• A study published in 2009 measured the entrance skin dose (ESD) at different positions on the patient during diagnostic angiography of the lower limbs, with mean ESD values ranging from 9.7 mGy at the feet to 70.8 mGy at the level of the aorta bifurcation 2.
• The average effective dose for the patient was calculated to be 9.8 mSv, with a corresponding radiation risk for fatal cancer of 5.4 x 10(-4) 2.
• The study also estimated the effective dose to the radiologist to be 0.023 mSv per procedure, which is considered negligible 2.
• Based on the measurements, a local dose reference level (DRL) was established for digital subtraction angiography (DSA) of the lower limbs, with an entrance skin dose of 96.4 mGy in the pelvic region 2.

Comparison with Other Studies

• Other studies have focused on the techniques and contrast agents used in lower-limb angiography, rather than specifically addressing radiation exposure 3, 4, 5, 6.
• These studies have compared the efficacy and safety of different contrast agents, such as iodixanol and iohexol, and have evaluated the quality of angiograms obtained using different techniques and volumes of contrast material 4, 5, 6.