Ch 10 Dose limits

Page 5: Health Policy

Defining Health Policy

• Health policies include decisions, plans, and actions to achieve specific healthcare goals.

• Composed of statutes and regulations.

Page 6: Health Physics

Focus of Health Physics

• Health physics is concerned with providing occupational radiation protection.

• Aims to minimize radiation dose to the public.

Page 7: Involvement in Health Policy

Activism in Health Policy

• Encourage active participation in state and national societies to influence health policy.

• voting, running for office, going to meetings

Page 8: Organizations for Radiation Protection Standards

Organizations

• International Commission on Radiological Protection (ICRP)

• National Council on Radiation Protection and Measurements (NCRP)

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

• NAS/NRC Committee on Biological Effects of Ionizing Radiation (BEIR)

Page 9: Summary of Functions of Standards Organizations

Function of Each Organization

ICRP

• Evaluates biologic effects of radiation; provides guidance on dose limits.

NCRP

• Reviews ICRP regulations and formulates U.S. radiation protection criteria.

UNSCEAR

• Evaluates human/environmental exposure to ionizing radiation.

NAS/NRC-BEIR

• Reviews studies on biologic effects and assesses risks, providing information for evaluation.

Page 10: NCRP

Role of NCRP

• Publishes radiation protection recommendations; not an enforcement agency.

• Radiation exposure limits established by Congress, referencing NCRP Report No. 116.

Page 11: U.S. & State Regulatory Agencies

Key Agencies

• Nuclear Regulatory Commission (NRC)

• Agreement States

• Environmental Protection Agency (EPA)

• Food and Drug Administration (FDA)

• Center for Devices and Radiological Health (CDRH)

• Occupational Safety and Health Administration (OSHA)

• Ohio Department of Health (ODH)

Page 12: Function of U.S. Regulatory Agencies

Agency Functions

NRC

• Oversees nuclear energy industry, enforcing radiation protection standards.

Agreement States

• States work with NRC to regulate radiation use, enforcing protection regulations.

EPA

• Develops regulations for environmental radiation control.

FDA

• Regulates electronic product safety; monitors radiation exposure in medical devices.

OSHA

• Monitors radiation exposure in workplaces.

Page 13: NRC Definition and Functionality

NRC Overview

• Regulates and licenses to protect radiation workers’ health.

• Functions as an enforcement agency transferring authority to states.

Page 14: Agreement States

Definition

• States entering agreements with NRC to enforce radiation regulation through health departments.

• Non-agreement states will coordinate with NRC for facility inspections.

Page 15: State Regulations Overview

State Regulatory Legislation

• Legend detailing states according to their regulation of radiologic disciplines.

• Highlights three levels of state involvement in regulating radiology.

Page 16: Environmental Protection Agency (EPA)

EPA Role

• Responsible for controlling radiation in the environment.

Page 17: Food and Drug Administration (FDA)

FDA Responsibilities

• Regulates design/manufacture of electronic products, requiring incident reporting of safety breaches.

• Promotes safety in Computed Radiography (CR) and Digital Radiography (DR).

Page 18: Center for Devices and Radiological Health (CDRH)

CDRH Function

• Part of FDA.

• Evaluates population exposure to imaging techniques; regulates x-ray equipment performance.

Page 19: Radiation Control for Health and Safety Act of 1968

Act Overview

• Protects public from hazards of radiation in products, setting standards for x-ray equipment manufacturing.

Page 20: Consumer-Patient Radiation Health and Safety Act of 1981

Act Provisions

• Establishes minimum educational standards and certification for radiologic technologists.

• Ensures safety standards for medical and dental procedures related to radiation.

Page 21: Radiation Safety Program

Overview of Safety Programs

• Facilities must maintain effective radiation safety programs.

• NRC mandates formation of a Radiation Safety Committee (RSC) and appoints a qualified RSO.

Page 22: Role of Radiation Safety Officer (RSO)

RSO Responsibilities

• Oversees RSC operations and ensures compliance with guidelines.

• Develops a safety program and maintains records.

Page 23: RSO Qualifications

Qualifications Required

• Must be certified by NRC with relevant experience and be an authorized user of ionizing radiation.

Page 24: Code of Standards for Diagnostic X-ray Equipment

Standards Overview (1974)

• Standards include positive beam limitation, appropriate filtration, reproducibility, visual indicators, and manual timers.

Page 25: ALARA Principle

ALARA Introduction

• Established in 1954 – encourages minimizing radiation exposure.

• Endorsed by regulatory agencies to ensure safety in medical imaging.

Page 26: ALARA and Risk Assessment

Risk Assessment Model

• Presumes a conservative approach to ionizing radiation effects and promotes caution over optimism in risk estimations.

Page 27: Goals for Radiation Protection

Radiation Protection Goals by NCRP

• To prevent serious radiation-induced conditions and reduce stochastic effects in relation to benefits from exposures.

Page 28: Categories of Radiation-Induced Responses

Main Categories

• Non-stochastic Effects: Occur above a certain dose threshold.

• Stochastic Effects: Probability increases with dose; all exposure is considered hazardous.

Page 29: Deterministic (Non-stochastic) Effects

Characteristics

• Effects are dose-related and have a threshold; severity increases with dose.

• Typically not seen in diagnostic x-ray.

Page 30: Deterministic Effects Overview

Additional Notes

• Exhibit a non-linear threshold relationship; severity does not proportionally align with dose.

Page 31: Stochastic Effects

Characteristics

• Probabilistic outcomes related to exposure; risks increase with higher doses.

• Non-threshold effects include cancer and genetic changes.

Page 32: Current Radiation Protection Philosophy

Philosophy Overview

• Linear non-threshold relationship exists; all doses carry some risk.

• Justification for exposure relies on balancing benefits against potential risks.

Page 33: Minimizing Risk of Ionizing Radiation

Goals of Risk Mitigation

• Limit exposure of public and workers; regulate through defined EfD and EqD limits.

Page 34: Effective Dose Limiting System

Concept Overview

• Analyzes risks associated with radiation exposure; advocates for adherence to established limits.

Page 35: System Focus

Focus of Limiting System

• Establishes an upper boundary for ionizing radiation exposure, ensuring negligible risk to health.

Page 36: Occupational Exposure Limits

Recommendations

• Limits integrate an upper boundary reflective of risks similar to safer industries.

Page 37: Detailed Occupational Limits

Age-Based Recommendations

• NCRP suggests keeping lifetime EfD below 10 mSv multiplied by age in years.

Page 38: Annual Occupational Dose Limits

Proposed Changes

• Currently set at 50 mSv; under review to potentially lower to 20 mSv based on new data.

Page 39: Non-Occupational Exposure Limits

Annual Limits Overview

• Separate limits for non-occupational exposure (5 mSv and 1 mSv yearly).

Page 40: Summary Table of Dose Limits

Dose Limits Overview

• Includes comprehensive limits for technologists, students, and general public defined in a table format.

Page 41: Summary for Partial Body Exposure Limits

Key Limits

• Detailed exposure limits for specific body areas including the lens of the eye and skin, with memorization aid emphasized for exams.

Page 42: Action Limits and Responses

Institutional Protocols

• Facilities should investigate unusual dosimeter readings; action limits established by RSO.

Page 43: Radiation Hormesis

Concept Overview

• Suggests small radiation exposures could potentially be beneficial; a cautious approach is still recommended.