Rad Protection Unit 2

dose limits

What are Radiation Protection organizations responsible for?

• evaluating the relationship between radiation equivalent dose and induces biological effects

• formulate risk estimates of somatic and genetic effects of irradiation

ICRP stands for

International Commission on Radiological Protection

ICRP function

• evaluates information on biologic effects of radiation

• provides radiation protection guidance through general recommendations on occupational and public dose limits

NCRP stands for

National Council on Radiation Protection and Measurements

NCRP function

reviews regulations formulated by ICRP and decided ways to include them into US radiation protection criteria

NAS/ NCR-BEIR stands for

National Academy of Sciences/ National Research Council Committee on the Biological Effects of Ionizing Radiation

NAS/NCR-BEIR function

• reviews studies of biologic effects of ionizing radiation and risk assessment

• provides the information to organizations such as ICRP for evaluation

What does the International Commission on Radiological Protection do?

• international authority on the safe uses of ionizing radiation

• provides clear and consistent guidance for both occupational and public dose limits

• makes recommendations but does not enfore them

  • publishes articles in scholarly journals and shared by UNSCEAR and NAS/NRC/BEIR

• each nation must develop and enforce specific regulations

what does the National Council on Radiaiton Protection and Measurements do?

• nongovernmental, nonprofit, private corporation in United States chartered by Congress in 1964

• reviews recommendations from ICRP and how they will be incorporated into US protection criteria

• assembles relevant guidelines and publishes them into NCRP reports

• not an enforcement agency

  • recommendations must be enforced by the state and federal agencies

what does the National Academy of Sciences/ National Research Council Committee on the Biological Effects of Ionizing Radiation do?

• reviews studies of biologic effects of radiation and risk assessment

• BEIR reports list studies of biologic effects and associated risk of group of people who were routinely or accidentally exposed

  • early radiation workers

  • atomic bob victims of Hiroshima and Nagasaki (1945)

  • Victims from the Chernobyl nuclear power station disaster (1986)

  • Fukushima (2011)

ICRP, NCRP and NAS/NCR-BEIR

• recommends limits for effective and equivalent dose limits to radiation exposures

• based on recommendations, limits are established by congressional act or mandated by the individual states

• National and state agencies are responsible for enforcing the standards after they are established

Code of Federal Regulations

the CFR is the codification of the general and permanent rules published in the federal register by the departments and agencies of the Federal Government

CFR 10; part 20

• standards for protection against radiation

• includes subparts such as

  • occupational dose limits for adults

  • dose equivalent to an embryo/fetus

  • radiation dose limits for individual members of the public

CFR 21

• food and drug administration

• minimum source-to-skin distance

• guidelines for fluoroscopy and mobile units

US Regulatory Agencies

• after radiation protection standards have been determined, responsible agencies enforce them for the protection of the general public, patients and occupationally exposed

NRC stands for

National Regulatory Committee

NRC function

• oversees nuclear energy industry

• enforces radiation protection standards

• published rules/ regulations in Title 10 CFR

• enters into written agreeements with state governments permitting state to license use of radioisotopes/ NM materials in their state

agreement states function

enforces radiation protection regulations through each state health departments

EPA stands for

environmental protection agency

EPA function

• facilitates developments and enforcement of regulations pertaining to control of radiation in environment

FDA stands for

US Food and Drug Administration

FDA function

• conducts ongoing product radiation control program, regulating design and manufacturing of electronic products, including x-ray equipment

OSHA stands for

Occupational Safety and Health Administration

OSHA function

agency who monitors in places of employment/industries

what does the Nuclear Regulatory commission do?

• controls atomic energy for national security

• primary function is to oversee nuclear energy industries

• controls the manufacture and use of radioisotpoes formed in nuclear reactors

• has power to enfore radiation protection standards

  • does not regulate or inspect x-ray facilities

• writes standards that are presented as rules and regulations and publish to Tite 10 of US CFR

NARM stands for

naturally occuring and/ or accelerator produced materials

NARM is

radioactive substances that are produced outside of a reactor by high-energy particle accelerators; cyclotrons

NARM examples

Thallium-201 and Palladium-103

Thallium-201

nuclear medicine for heart stress tests

Palladium-103

used for therapeutic prostate seed implants

what does the environmental protection agency do?

• responsible for protecting the health of humans and safeguarding the natural environment from industrial practices and harmful waste disposal

• oversees development and enforcement of regulations for radiation in the environment

  • directs relevant agencies

  • oversees general area of environemntal monitoring

  • determines levels of radon

what does the US Food and Drug Administration do?

• conducts ongoing radiaiton control program

• regulates design and manufacturing of electronic products, including diagnostic equipment

• does onsite inspections of equipment, especially mammography to determine level of compliance

  • mammography Quality Standards Act- 1992; MQSA

• compliance ensures protection to the user and the patient from faulty manfacturing; protecting and promoting public health

• Radiopharmaceuticals fall under FDA regulations

what does OSHA do?

• monitoring agency in places of employment, industry

• regulates occupational exposures

• regulates “right to know” of employees, must provide training and written information. Must be aware of risks:

  • hazardous substances

  • infectious agents

  • ionizing radiation

  • non-ionizing radiation (UV, microwaves)

• employers required to evaluate for harmful agents and provide training and written information; must provide proper training

What are agreement states?

• US states that have agreements with the NRC to allow the state to take responsibility for licensing, inspecting, and regulating radioactive materials within that state

  • responsible for enforcing radiation protection regulation through state health departments

• Non-agreement states: NRC retains direct control of the regulation of radioactive materials

• PA is an agreement state since March 31, 2008

• Nuclear reactors must be inspected by the NRC

State agencies

• Department of environmental protection (DEP)

• Department of Health (DOH)

• PA patient safety authority

Department of Environmental Protection (DEP)

• Bureau of Radiation Protection directs the statewide radiation protection program with the goal of protecting from unnecessary exposure to radiation

  • performs suprise hospital visits

Department of Health (DOH)

• responisble for the licensing and oversight of PA’s hospitals

• imaging/ Radiology and Nuclear Medicine departments

• does onsite inspections

PA Patient Safety Authority

adverse patient events are reported

department of transportation

• works with NRC to set safety rules for shipping radioactive materal

• NRC oversees the design and use of special packaging for shipping radioactive materials

• DOT oversees safety during the actual transportation

Radiation safety programs requirements

• imaging facilities must have an effective and detailed program to ensure appropriate safety of patients and technologists

• beginnings with administration

  • delegate funds in the budget

  • oversee development of policies and procedures

  • provide equipment necessary for starting and maintaining the program

RSC stands or

radiation safety committee

whats does the RSC do?

• required by NRC to oversee radiation safety programs

• provides guidance and ensures compliance with regulations at the facility

  • regulations from CFR 10 part 20

• each committee is developed by a Radiation Safety Officer (RSO)

Radiation Safety Officer (RSO) responsibilities

• develops and oversees radiation safety program

• implement and enforces policies of the committee

• ensures everyone is adequately protected; pregnancy

• maintains monitoring records and counsels’ individuals with high readings

• day to day supervision of safety program

• indentifies safety problems, provides corrective actions, and verifies these actions were followed through

• provides information for a formal review annually

qualifications for RSO

• usually a medical or health physicist, radiologist, or individual deemed qualified by training and experience

• Listed in Title 10 of the Code of Federal regulations (CFR)

• needs to be approved by the NRC and at the state

authority for the RSO

• able to stop operations that they consider unsafe

• ensures and/or initiate corrective action

• identify radiation safety problems

• given sufficient time and resources to ensure the program is running properly

ALARA principle

developed in 1954 by the NCRP

what is ALARA

• accepted by all regulatory agencies

• this is a joint effort of the technoloist and physician to achiebe for both occupational and non-occupational exposure

• also referred to as optimization by ICRP

• extremely conservative level- linear, non threshold

  • effects and dose are directly proportional, withougt a threshold

• achieved by proper safety procedures and qualified workers

Consumer-Patient Radiation Health and Safety Act of 1981 is also known as

Public law 97-35

Consumer-Patient Radiation Health and Safety Act of 1981 is

• minimize unnecessary exposure to potentially hazardous radiation due to medical and radiology procedures

  • public should always have adequately educated/ trained persons with appropriate accreditation and certification programs

• within a year after this act was in place, standards and certifications were distinguished

  • radiologic technologists

  • dental hygenists/ assistants

  • radiation therapists

  • nuclear medicine technologists

  • other health auxillaries using radiation

NCRP Report #102

• came out in 1989

• recommendations on equipment design, sheilding and sue of equipment

• guidelines for:

  • minimum shielding (lead- Pb) equivalent

  • minimum filtration (aluminum- Al) required

  • guidelines for mobile and fluoro exposure rates

NCRP Report #116

• 1993, basic radiation protection criteria

• limitation of exposure to ionizing radiation

  • effective dose limits

    • occupational

    • non-occupational

    • cumulative effective dose

• somatic and genetic effects kept to a minimum

NRCP Report #160

• came out in 2009

• provides a complete review of all radiation exposures for 2006 in the US

  • 7x more since 1980’s according to the NCRP

  • mainly CT and NM

• substantial reduction in radiation doses in US population

radiation induced responses

• tissue reactions (deterministic)(nonstochastic)

  • somatic effects directly related to the dose received

  • early and late tissue interactions

• stochastic (probabilistic) effects-

• randomly occuring

tissue response/ non-stochastic (deterministic)

• effects of radiation that become more severe at higher levels of radiation exposure

• do not typically occur below a certain threshold

  • could result from long-term individual low doses over several years

• as dose increases, severity of biologic damage increases because greater # of cells interact with the increased # of x-ray photons

early examples of tissue interactions

• erythema

• decreased WBC (leukemia)

• epilation

more severe early examples of tissue interactions

• hematopoietic syndrome

• gastrointestinal syndrome

• cerebrovascular syndrome

late examples of tissue interactions

• cataracts

• fibrosis

• organ atrophy

• reduction of fertility

• sterility

stochastic (probabilistic)

• non-threshold, randomly occurring

• chance of occurrence increases with each exposure, probability increases also

• random effects, cannot determine who will be effected

• assumption that no minimal safe dose exists

examples of stochastic (probabilistic) effects

• cancer

• genetic alterations

  • teratogenesis- radiation of the fetus in utero

  • mutagenesis- radiation of reproductive cells before conception

• occurrence of radiation induced malignancy

  • chance increases with an increased dose to the somatic cells

  • severity is not dose related, but the chance increases as the dose increases

objective of radiation protection

• prevent non-stochastic (tissue response/ deterministic) effects from happening by keeping dose limits below thresholds

• limit risk of stochastic (probalilistic) effects to a conservative level as comapred to the benefit of the exposure

philosophy of radiation protection

• linear, non threshold

  • chance of occurrence increases with each exposure, probability increase also

• chance of biologic damage and amount of damage are directly proportional

• smallest dose has potential to cause harm

• radiation has benefits but has potential for destruction

• must weigh the benefit of the exposure against the risk

tissue weighting factor

tissues and organs vary in sensitivity to biological effects

critical organs examples

• gonads

• blood forming organs such as red bone marrow

• lung tissue

• thyroid

medium sensitivity examples

• osteoblast

  • bone forming

• fibroblast

  • connective tissue

low sensitivity examples

• muscle cells

• nerve cells

law of Bergonie and Tribondeau

cells are more sensitive when they are immature and rapidly dividing

occupational annual limits/ equivalent dose limits

• effective dose limit:

  • annual: 50mSv whole-body

  • cumulative: 10mSv x age in years

• lens of eye: 150mSv

• localized skin area (hands, skin, feet): 500mSv

• ICRP has lowered effective dose limit to 20 mSv, but the US has not yet adopted this rate

Cumulative effect dose (CumEfD)

• to ensure that the lifetime risk for radiation workers is no greater than the public, NCRP proposes no dose based on the below

  • persons age in year x 10mSv

  • pertains to the whole body

  • also known as the cumulative dose formula

• example:

  • persin is 56 years old= 560mSv

non-occupational dose limits

• public exposed

  • 1mSv- continuous exposure

  • 5mSv- infrequent exposed

  • these limits are set for people who have accompany a patient to radiaology (spouse, parent, gaurdian)

• Hospital employees who are not radiology employees:

  • 1mSv

• there is not a specific dose limit for patients that are being imaged

limits for pregnant radiation workers

• not exceeding 0.5mSv to the embryo-fetus in any one month

• not exceeding 5mSv entire gestational period

• exclused personal medical and natural background radiation

students under the age of 18

• 1mSv

• occasional exposure for educational purposes/training is acceptable, special care must be taken to ensure annual EfD is not exceeded

NID stands for

negligible individual dose

what is negligible individual dose

• provides a low level cut off for regulatory agencies

• reduction in level is unnecessary; dismissed becuase the level is very low; 0.01 mSv per report 116