Chapter 6 Notes: Radiation Protection Organizations

Introduction

  • The safety standards, guidelines, and recommendations for prudent use of radiation in medicine come from the work of dedicated organizations worldwide.
  • This chapter explains the nature, goals, and major activities of international and national radiation protection groups relevant to diagnostic radiology, and identifies key reports dealing with diagnostic radiology protection.
  • Organizations are divided into international vs. national; some focus on biological effects, others on protection principles, concepts, and practices.

International Organizations

  • Five key international bodies highlighted:
    • International Commission on Radiological Protection (ICRP)
    • International Commission on Radiation Units and Measurements (ICRU)
    • United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)
    • Radiation Effects Research Foundation (RERF)
    • Biological Effects of Ionizing Radiation Committee (BEIR)

International Commission on Radiological Protection (ICRP)

  • Highly influential for diagnostic radiology; makes major recommendations on radiation protection based on biological effects data from BEIR, UNSCEAR, and RERF.
  • History and role:
    • Formed in 1928 by the Second International Congress of Radiology as the International X-Ray and Radium Protection Committee.
    • Renamed ICRP in 1950 to reflect broader protection role.
    • Core approach: base recommendations on fundamental principles; national bodies develop country-specific standards, regulations, and guidelines.
  • Composition and collaborations:
    • Members are experts in radiology, physics, radiobiology, health physics, genetics, biochemistry, biophysics.
    • Active relationships with ICRU, WHO, IAEA, IRPA, and others.
  • Publication history and major shifts:
    • First recommendations published in 1928 (x-ray and radium protection).
    • Major milestone publications:
    • 1964 (Publication 6)
    • 1990 (Publication 60)
    • Key 1977 shift (Publication 26): introduced the current system based on three principles and the distinction between stochastic (genetic) and non-stochastic/deterministic effects.
    • 1991 revision (Publication 60) following BEIR V findings; risks estimated to be ~3–4× higher than previously thought.
    • 2007 (Publication 103): major update after eight years of discussion; summarized by Valentin (2007).
  • 2007 ICRP recommendations (major features):
    • Updated radiation and tissue weighting factors.
    • Maintain the three core principles: justification, optimization, and dose limits.
    • Maintain individual dose limits.
    • Reinforce optimization.
    • Include a framework to demonstrate radiological protection of the environment.
    • Transition from a process-based approach to a situation-based approach for controllable exposure situations (planned, emergency, existing exposure conditions).
  • Publications (examples of importance to radiology staff):
    • ICRP Publication 93: Managing Patient Dose in Digital Radiology. Ann ICRP. 2004.
    • ICRP Publication 102: Managing Patient Dose in MDCT. Ann ICRP. 2007.
    • ICRP Publication 103: 2007 Recommendations of the ICRP (Users Edition). Ann ICRP. 2007.
    • ICRP Publication 113: Education and Training in Radiological Protection for Diagnostic and Interventional Procedures. Ann ICRP. 2009.
    • ICRP Publication 117: Radiological Protection in Fluoroscopically Guided Procedures outside the Imaging Department. Ann ICRP. 2010.
    • ICRP Publication 121: Radiological Protection in Paediatric Diagnostic Radiology. Ann ICRP. 2013.
    • ICRP Publication 127: Radiological Protection in Ion Beam Radiotherapy. Ann ICRP. 2014.
    • ICRP Publication 128: Radiation Dose to Patients from Radiopharmaceuticals. Ann ICRP. 2015.
    • ICRP Publication 129: Radiological Protection in Cone Beam CT (CBCT). Ann ICRP. 2015.
  • Relationships:
    • Works with its sister body ICRU; maintains official relationships with UNSCEAR, WHO, IRPA, etc.
  • Current scope (as of 2015): ~147 publications available to users.

International Commission on Radiation Units and Measurements (ICRU)

  • Established in 1928 to develop internationally accepted recommendations for radiation quantities and units, measurement procedures, and reporting.
  • Focus areas:
    • Uniform reporting of radiation quantities and data.
    • Occupational radiation protection, including radiotherapy and medical imaging (radiology, CT, nuclear medicine).
  • Encourages national bodies to adopt procedures and to align with universal concepts of radiation quantities/units.
  • Recent/notable work: Report 74 — Patient Dosimetry for X-Rays Used in Medical Imaging (ICRU 2005).

United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)

  • Established in 1955 by the UN General Assembly; composed of expert radiologists from around the world (27 contributing countries).
  • Mission:
    • Review current data on risks from natural and artificial radiation sources (e.g., RERF, major epidemiological and animal studies).
    • Monitor developments in radiobiology to track biological effects at systemic and cellular levels.
    • Predict population-level incidence of biological effects.
  • Major activity:
    • Publishes comprehensive risk assessments based on available biological evidence.
  • Major reports (selected):
    • UNSCEAR 2012: Biological mechanisms of radiation actions at low doses.
    • UNSCEAR 2010: Summary of low-dose radiation effects on health.
    • UNSCEAR 2008: Source and effects of ionizing radiation, Vol. 1 (medical exposures) and Vol. 2 (accidents, Chernobyl, non-human biota).
    • UNSCEAR 2006: Effects of ionizing radiation, Vol. 1 (epidemiology of cancer, etc.) and Vol. 2 (delayed effects, radon).
    • UNSCEAR 2001: Hereditary effects of ionizing radiation.

Radiation Effects Research Foundation (RERF)

  • Scientific research institution championed by the government of Japan with support from the United States.
  • Objective: conduct research on medical effects of radiation and related diseases in humans, aimed at maintaining the health/welfare of atomic bomb (A-bomb) survivors and the broader population.
  • Important note: RERF data are statistical and used by other organizations to develop risk models and revise protection recommendations.
  • Population of interest: Hiroshima and Nagasaki A-bomb survivors.

Biological Effects of Ionizing Radiation Committee (BEIR)

  • Formed by the US National Research Council (NAS) and NAS/NRC; not strictly international, but highly influential globally.
  • Evolution: BEIR I through BEIR VII, with BEIR V (1986) focusing on information since BEIR III to reassess genetic and somatic risks.
  • Influence on protection standards:
    • BEIR V concluded that radiation risks are about 3–4× higher than previously estimated (driving changes in policy).
    • BEIR VII, Phase 2 (2006): Health risks from low levels of ionizing radiation; supports the linear-no-threshold (LNT) model for cancer risk at low doses.
    • BEIR VII summary (NRC): supports Cancer and leukemia risk estimates and endorses the LNT model for low-dose exposures.

National Organizations

  • National organizations provide country-specific recommendations on radiologic protection for their jurisdictions.
  • Major groups discussed here: United States, Canada, United Kingdom.

National Council on Radiation Protection and Measurements (NCRP) – United States

  • Establishment: non-profit, chartered by US Congress in 1964 to replace the earlier Advisory Committee on X-Ray and Radiation Protection (founded 1929).
  • Structure: main committee plus scientific subcommittees; composed of experts in radiation protection.
  • Function: prepare reports on radiation protection issues to guide policy and practice; over 150 reports produced.
  • Four major charter objectives:
    1) Collect, analyze, develop, and disseminate information and recommendations about protection against radiation and about radiation quantities/units.
    2) Provide a mechanism for cooperation among organizations concerned with radiation protection and related measurements.
    3) Develop basic concepts about quantities, units, measurements, and their application to protection.
    4) Cooperate with ICRP, Federal Radiologic Council, ICRU, and other national/international bodies.
  • Not a government agency; its recommendations influence local, state, and federal policy.
  • Notable NCRP reports relevant to radiologic technologists:
    • No. 133: Radiation Protection for Procedures Performed Outside the Radiology Department (2000).
    • No. 147: Structural Shielding Design for Medical X-Ray Imaging Facilities (2004).
    • No. 149: A Guide to Mammography and Other Breast Imaging Procedures (2004).
    • No. 157: Radiation Protection in Educational Institutions (2007).
    • No. 160: Ionizing Radiation Exposure of the Population of the United States (2009).
    • No. 168: Radiation Dose Management for Fluoroscopically-Guided Interventional Medical Procedures (2010).
    • No. 174: Preconception and Prenatal Radiation Exposure—Health Effects and Protective Guidance (2013).

Center for Devices and Radiological Health (CDRH) – United States

  • Created by merging the Bureau of Radiological Health (BRH) and Bureau of Medical Devices (BMD).
  • Responsibility: oversees medical devices, including radiation-emitting equipment (diagnostic x-ray tubes).
  • Relevance: federal organization that evaluates population exposure to x-rays and other imaging modalities, plus radiotherapy.
  • Goal: minimize unnecessary radiation exposure by regulatory control of x-ray equipment performance; provides technical and biological background to the medical community and public.

Radiation Protection Bureau – Health Canada (RPB-HC)

  • Canadian federal organization addressing diagnostic radiology safety;
    • X-ray section focuses on safety procedures, equipment installation, and guidelines.
    • Non-ionizing radiation section covers microwaves, radio waves, and lasers.
  • Notable publication: Safety Code 35 (SC-35) – Radiation Protection in Radiology: Large Facilities (2008).
  • SC-35 goals:
    1) Minimize patient exposure while ensuring diagnostic information and treatment needs are met.
    2) Ensure adequate protection of personnel operating x-ray equipment.
    3) Ensure protection of other personnel and the public nearby where x-ray equipment is used.
  • SC-35 structure:
    • Section A: Responsibilities and Protection
    • Section B: Facility and Equipment Requirements
    • Section C: Quality Assurance Program

National Radiological Protection Board – United Kingdom (NRPB-UK)

  • UK radiation protection agency focused on research and technical advice for safe use of ionizing and non-ionizing radiations.
  • Functions included:
    • Optimization of protection, transport of radioactive materials, personnel dosimetry, education, and conducting radiation surveys.
  • Evolution:
    • Functions and activities later integrated into Public Health England's Radiation Protection Service (2005).
  • Note: historical NRPB reports and content can be accessed via UK archives.

Definition of Terms Used in Reports

  • Table 6-1 summarizes how three organizations use key terms:
    • ICRP: shall, should
    • NCRP (US): shall, should
    • RPB-HC (Canada): must, should
  • Table captures special meanings assigned by each organization to these terms in selected reports.

ICRP Definitions

  • Shall: Necessary or essential for radiation protection.
  • Should: To apply, whenever reasonable, in the interest of improving radiation protection.
  • Note: The negative forms of these terms have distinct meanings as well.

NCRP Definitions

  • Shall: Indicates a recommendation that is necessary or essential to meet the currently accepted standards of radiation protection.
  • Should: Indicates an advisory recommendation that is to be applied when practicable; equivalent to "is recommended" or "is advisable".

RPB-HC Definitions (Canada)

  • Must: Indicates a requirement that is essential to meet the currently accepted standards of protection.
  • Should: Advisory recommendation that is highly desirable and should be implemented where practicable.

Radiation Protection Recommendations – Common Elements

  • Across ICRP, NCRP, and RPB-HC SC-35, there are common elements guiding protection for diagnostic radiology:
    • Example: Holding patients during examinations
    • Guiding principles in practice:
    • 1) A restraining device should be used to immobilize patients during examinations.
    • 2) Individuals holding patients shall and must be protected by wearing lead aprons and lead gloves.
    • 3) No part of the shielded body of those who hold patients is in the direct path of the primary beam.
  • If national recommendations differ from ICRP, national standards should be more stringent and not lower than ICRP.
  • Filtration example:
    • ICRP recommends total x-ray beam filtration of 2.5 mm aluminum equivalent2.5\,\text{mm aluminum equivalent} for equipment operating above 70 kVp70\,\text{kVp}.
    • National standards should meet or exceed this requirement (i.e., filtration greater than 2.5 mm Al at the same kVp if chosen).
  • Main takeaway:
    • The primary goal is to understand major recommendations for safe use of radiation in imaging; the secondary goal is to recognize common elements across guidelines and standards.

Summary Of Key Concepts

  • This chapter reviews international and national radiation protection organizations and their contributions to protecting patients, staff, and the public in diagnostic radiology.
  • International organizations highlighted: ICRP, ICRU, UNSCEAR, RERF, BEIR.
  • ICRP is especially influential due to its role in formulating protection principles based on biological effects data from BEIR/UNSCEAR/RERF.
  • ICRP has published many reports; notable themes and publications include:
    • ICRP 93: Managing Patient Dose in Digital Radiology (2004).
    • ICRP 102: Managing Patient Dose in MDCT (2007).
    • ICRP 103: 2007 Recommendations (Users Edition) (2007).
    • ICRP 113: Education and Training in Radiological Protection (2009).
    • ICRP 117: Protection in Fluoroscopically Guided Procedures outside the Imaging Department (2010).
    • ICRP 121: Paediatric Radiological Protection (2013).
    • ICRP 127: Ion Beam Radiotherapy Protection (2014).
    • ICRP 128: Dose to Patients from Radiopharmaceuticals (2015).
    • ICRP 129: Cone Beam CT (CBCT) Protection (2015).
  • The current system (as of 2015) is based on three core principles:
    • Justification\text{Justification}
    • Optimization\text{Optimization}
    • Dose limits\text{Dose limits}
  • ICRU focuses on radiation quantities/units and measurement procedures; Report 74 (2005) pertains to patient dosimetry in medical imaging.
  • UNSCEAR studies risk from radiation across populations and makes predictions about incidences of effects; major reports span 1977–2012 and cover low-dose effects, source and effects, hereditary effects, and epidemiology.
  • RERF provides statistical data on the health effects of radiation among the Hiroshima/Nagasaki survivors; data influence BEIR and ICRP recommendations.
  • BEIR reports (I–VII) study health effects of ionizing radiation; BEIR V (1990) expanded risk estimates; BEIR VII (2005) supports the linear-no-threshold (LNT) model for cancer risk at low doses:
    • BEIR VII (Phase 2) conclusions: health risks from low-dose ionizing radiation; supports LNT model.
  • National organizations:
    • NCRP (US): non-profit, influential in shaping policy; numerous reports; four main objectives (as noted in NCRP charter).
    • CDRH (US): regulatory body for medical devices including x-ray equipment; seeks to minimize unnecessary exposure via regulation and information.
    • RPB-HC (Canada): publishes Safety Code 35; promotes patient and personnel protection; three-part SC-35 structure (A: Responsibilities/Protection, B: Facility/Equipment, C: Quality Assurance).
    • NRPB-UK (UK): historical radiation protection authority; research and technical advice; functions now housed in Public Health England’s Radiation Protection Service (as of 2005).
  • Practical implication:
    • National bodies often adopt ICRP principles but may impose more stringent requirements to reflect local contexts and practices.

Discussion Questions

  • 1) Discuss the role of the ICRP and identify several major reports relevant to the technologist. State the three major principles of radiation protection established by the ICRP.
  • 2) Identify several national radiation protection organizations and discuss the role of the NCRP and the CDRH in the US.
  • 3) Outline the definitions of "shall," "should," and "must" as used in the reports of the ICRP and the NCRP.
  • 4) Describe briefly what is meant by the common elements of the various radiation protection reports of the ICRP and the NCRP.

References (selected)

  • Berry RJ. The international commission on radiological protection. An historical perspective. In Russell J, Southwood R (Eds). Radiation and Health. New York, John Wiley and Sons; 1987.
  • Brown D. International bodies of importance for radiation protection practices in Canada. Bull Can Radiat Prot Assoc. 1989;10:9-15.
  • Bjarnason TA, Thakur Y, & Aldrich JE. Health Canada safety code 35: Awareness of the impacts for diagnostic radiology. Can J Radiol. 1987;64:6-9.
  • Health Canada. Radiation protection in radiology - Large facilities: Safety code 35. Ottawa: Government of Canada; 2008. (Available at: http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_35-securite/index-eng.php; Retrieved August 20, 2015.)
  • ICRU. Patient Dosimetry for X Rays used in Medical Imaging (Report 74). J ICRU 2005;5(2). (Available at: http://www.icru.org/home/reports/patient-dosimetry-for-x-rays-used-in-medical-imaging-report-74)
  • ICRP. 1990 Recommendations of the ICRP (Publication No. 60). Elmsford, NY: Pergamon Press; 1991.
  • ICRP. About the ICRP. (Available at www.icrp.org; Retrieved August 20, 2015.)
  • NRC BEIR Committee. The effects on populations of exposure to low levels of ionizing radiations. Washington, DC: National Academy of Sciences/National Research Council; 1990.
  • NRC. BEIR VII: Health risks from exposure to low levels of ionizing radiation. Washington, DC: National Academies Press; 2005.
  • NCRP (2010). Our Mission. (Available at www.ncrponline.org/About NCRP/Our Mission.html; Retrieved August 20, 2015.)
  • NCRP. NCRP No. 133: Radiation protection for procedures performed outside the radiology department. Bethesda, MD; 2000.
  • NCRP. NCRP No. 147: Structural Shielding Design for Medical X-Ray Imaging Facilities (2004).
  • NCRP. NCRP No. 149: A Guide to Mammography and Other Breast Imaging Procedures (2004).
  • NCRP. NCRP No. 157: Radiation Protection in Educational Institutions (2007).
  • NCRP. NCRP No. 160: Ionizing Radiation Exposure of the Population of the United States (2009).
  • NCRP. NCRP No. 168: Radiation Dose Management for Fluoroscopically-Guided Interventional Medical Procedures (2010).
  • NCRP. NCRP No. 174: Preconception and Prenatal Radiation Exposure—Health Effects and Protective Guidance (2013).
  • O'Riordan MC. The NRPB Era. J Radiol Prot. 2010;30(1):85-92.
  • RERF. Radiation Effects Research Foundation. (Available at www.rerf.jp/intro/establish/index_e.html).