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
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
Related Anatomy
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Related Differential Diagnoses
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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
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
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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