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KEY FACTS
Terminology
Preprocedure
Post Procedure
TERMINOLOGY
Definitions
- As low as reasonably achievable (ALARA): Effort to maintain exposures to radiation as far below dose limits as is practical
Radiation Basics
- Absorbed dose: Amount of energy absorbed by matter
- Measured in gray (Gy), which is standard international (SI) unit
- 1 Gy = 1 joule/kg
- Radiation-absorbed dose (rad); outdated unit
- 0.01 Gy = 1 rad
- Equivalent dose: Radiation dose weighting based on harmful biologic effect of dose
- Measured in sieverts (Sv), which is SI unit
- 1 Sv = 1 joule/kg
- Sv and Gy are not interchangeable; however, for IR procedures, weighting factor is 1, so Sv and Gy are equal
- 1 Sv = 100 roentgen equivalent man (rem), which is non-SI unit
- 1 rem increases chance of cancer by 0.055% over lifetime
- Millirem (mrem): Often used to describe medical device dosage
- Denote stochastic biologic effects of ionizing radiation
- 5000 mrem = maximum allowed effective dose to physician body/year
- 300 mrem = typical natural background radiation/year
- Effective dose: Equivalent dose accounting for tissue/organ sensitivity and specific damage from radiation
- Measured in Sv (SI) or rem (non-SI)
- Effects of ionizing radiation
- Deterministic
- Effects exhibit threshold; below threshold, effect is not observed
- Severity of effect increases with increasing dose above threshold (e.g., radiation-induced hair loss, skin injury, cataracts, sterility)
- Stochastic
- Probabilistic; nondeterministic health effects
- Probability of event increases linearly with increasing dose without threshold, but severity of effect is constant (e.g., cancer)
- Biologic effect of radiation doses to whole body
- 10 Sv: High probability of death within days/weeks
- 1 Sv: 5.5% ↑ probability of cancer during lifetime
- 100 millisieverts (mSv): 0.5% probability of cancer during lifetime
- Radiation risk is inversely related to patient age
- Sequela of radiation exposure is often delayed, frequently weeks to months after exposure
- Deterministic
- Absorbed dose: Amount of energy absorbed by matter
PREPROCEDURE
Preprocedure Imaging
Getting Started
PROCEDURE
Ways to Reduce Patient Dose in Fluoroscopy
Ways to Reduce Operator Dose in Fluoroscopy
Ways to Reduce Patient Dose in CT
Pregnant Patient Guidelines
POST PROCEDURE
Expected Outcome
Things to Do
Selected References
- Ji YS et al: Radiation-shielding devices: the best combination for spine interventional procedures. J Vasc Interv Radiol. ePub, 2021
- Mettler FA Jr et al: Patient exposure from radiologic and nuclear medicine procedures in the United States: procedure volume and effective dose for the period 2006-2016. Radiology. 295(2):418-27, 2020
- National Council on Radiation Protection and Measurements: Medical radiation exposure of patients in the United States, NCRP report 184, Bethesda, MD: National Council on Radiation Protection and Measurements, 2019
- Lichliter A et al: Clinical evaluation of protective garments with respect to garment characteristics and manufacturer label information. J Vasc Interv Radiol. 28(1):148-55, 2017
- Vlastra W et al: Efficacy of the RADPAD protection drape in reducing operators' radiation exposure in the catheterization laboratory: a sham-controlled randomized trial. Circ Cardiovasc Interv. 10(11), 2017
- United States Nuclear Regulatory Commission: NRC Regulations (10 CFR) part 20: Standards for protection against radiation. Published June 31, 2015. Reviewed February 25, 2022. Accessed February 25, 2022. http://www.nrc.gov/reading-rm/doc-collections/cfr/part020.
- Authors on behalf of ICRP et al: ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context. Ann ICRP. 41(1-2):1-322, 2012
- Bushberg JT: The Essential Physics of Medical Imaging. Philadelphia: Lippincott Williams & Wilkins, 2012
- Smith JC et al: Ultra-low-dose protocol for CT-guided lung biopsies. J Vasc Interv Radiol. 22(4):431-6, 2011
- Miller DL et al: Reference levels for patient radiation doses in interventional radiology: proposed initial values for U.S. practice. Radiology. 253(3):753-64, 2009
- Stecker MS et al: Guidelines for patient radiation dose management. J Vasc Interv Radiol. 20(7 Suppl):S263-73, 2009
- Schueler BA et al: An investigation of operator exposure in interventional radiology. Radiographics. 26(5):1533-41; discussion 1541, 2006
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References
Tables
Tables
KEY FACTS
Terminology
Preprocedure
Post Procedure
TERMINOLOGY
Definitions
- As low as reasonably achievable (ALARA): Effort to maintain exposures to radiation as far below dose limits as is practical
Radiation Basics
- Absorbed dose: Amount of energy absorbed by matter
- Measured in gray (Gy), which is standard international (SI) unit
- 1 Gy = 1 joule/kg
- Radiation-absorbed dose (rad); outdated unit
- 0.01 Gy = 1 rad
- Equivalent dose: Radiation dose weighting based on harmful biologic effect of dose
- Measured in sieverts (Sv), which is SI unit
- 1 Sv = 1 joule/kg
- Sv and Gy are not interchangeable; however, for IR procedures, weighting factor is 1, so Sv and Gy are equal
- 1 Sv = 100 roentgen equivalent man (rem), which is non-SI unit
- 1 rem increases chance of cancer by 0.055% over lifetime
- Millirem (mrem): Often used to describe medical device dosage
- Denote stochastic biologic effects of ionizing radiation
- 5000 mrem = maximum allowed effective dose to physician body/year
- 300 mrem = typical natural background radiation/year
- Effective dose: Equivalent dose accounting for tissue/organ sensitivity and specific damage from radiation
- Measured in Sv (SI) or rem (non-SI)
- Effects of ionizing radiation
- Deterministic
- Effects exhibit threshold; below threshold, effect is not observed
- Severity of effect increases with increasing dose above threshold (e.g., radiation-induced hair loss, skin injury, cataracts, sterility)
- Stochastic
- Probabilistic; nondeterministic health effects
- Probability of event increases linearly with increasing dose without threshold, but severity of effect is constant (e.g., cancer)
- Biologic effect of radiation doses to whole body
- 10 Sv: High probability of death within days/weeks
- 1 Sv: 5.5% ↑ probability of cancer during lifetime
- 100 millisieverts (mSv): 0.5% probability of cancer during lifetime
- Radiation risk is inversely related to patient age
- Sequela of radiation exposure is often delayed, frequently weeks to months after exposure
- Deterministic
- Absorbed dose: Amount of energy absorbed by matter
PREPROCEDURE
Preprocedure Imaging
Getting Started
PROCEDURE
Ways to Reduce Patient Dose in Fluoroscopy
Ways to Reduce Operator Dose in Fluoroscopy
Ways to Reduce Patient Dose in CT
Pregnant Patient Guidelines
POST PROCEDURE
Expected Outcome
Things to Do
Selected References
- Ji YS et al: Radiation-shielding devices: the best combination for spine interventional procedures. J Vasc Interv Radiol. ePub, 2021
- Mettler FA Jr et al: Patient exposure from radiologic and nuclear medicine procedures in the United States: procedure volume and effective dose for the period 2006-2016. Radiology. 295(2):418-27, 2020
- National Council on Radiation Protection and Measurements: Medical radiation exposure of patients in the United States, NCRP report 184, Bethesda, MD: National Council on Radiation Protection and Measurements, 2019
- Lichliter A et al: Clinical evaluation of protective garments with respect to garment characteristics and manufacturer label information. J Vasc Interv Radiol. 28(1):148-55, 2017
- Vlastra W et al: Efficacy of the RADPAD protection drape in reducing operators' radiation exposure in the catheterization laboratory: a sham-controlled randomized trial. Circ Cardiovasc Interv. 10(11), 2017
- United States Nuclear Regulatory Commission: NRC Regulations (10 CFR) part 20: Standards for protection against radiation. Published June 31, 2015. Reviewed February 25, 2022. Accessed February 25, 2022. http://www.nrc.gov/reading-rm/doc-collections/cfr/part020.
- Authors on behalf of ICRP et al: ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context. Ann ICRP. 41(1-2):1-322, 2012
- Bushberg JT: The Essential Physics of Medical Imaging. Philadelphia: Lippincott Williams & Wilkins, 2012
- Smith JC et al: Ultra-low-dose protocol for CT-guided lung biopsies. J Vasc Interv Radiol. 22(4):431-6, 2011
- Miller DL et al: Reference levels for patient radiation doses in interventional radiology: proposed initial values for U.S. practice. Radiology. 253(3):753-64, 2009
- Stecker MS et al: Guidelines for patient radiation dose management. J Vasc Interv Radiol. 20(7 Suppl):S263-73, 2009
- Schueler BA et al: An investigation of operator exposure in interventional radiology. Radiographics. 26(5):1533-41; discussion 1541, 2006
