Upload
uncehs
View
2.268
Download
0
Embed Size (px)
Citation preview
In this course, you will learn about:
Radioactivity and Radiation
Radiation Units and Terms
Background Radiation
Radioactive Materials
Signs and Labels
Radiation Risk Assessment
Radiation Protection at UNC
Radiation Safety Practices – ALARA
Basic Radiation Safety Procedures
Dose Limits and Monitoring Requirements
Guidelines for Working Safely Around Radiation Sources
Important Contact Information
DID YOU KNOW?
Wilhelm Conrad Roentgen
Discovered X-Rays in 1895
What is radiation?
Radiation is the transfer of energy
This course deals with ionizing radiation Radiation that creates ions X-rays, gamma rays, beta particles, neutrons
Comes from different sources: Unstable atoms Electrically or machine produced
Radioactivity and Radiation
Radiation is beneficial in medicine and research
Allows for the imaging, diagnosis, and treatment of internal structures and diseases
Uses at UNC-- X-ray machines
Radiopharmaceuticals
Linear accelerators and sealed sources
Research Labs
Radioactivity and Radiation
Radiation can not be seen, felt, smelled or tasted!
It can however be measured!
Terms used to describe radiation and radioactive materials:
Exposure (R – Roentgen)
Electrical charge per unit mass of air produced by x or gamma rays
Absorbed Dose (RAD – Radiation Absorbed Dose)
Amount of energy per unit mass absorbed by an irradiated object
Radiation Units and Terms
Dose Equivalent (REM – Roentgen Equivalent Man)
Modified absorbed dose
Regulatory dose reporting unit
Takes into account the biological impact of
the radiation (i.e. beta particle, x-ray, neutron)
Note: 1,000 (millirem) = 1 rem
Activity (Ci – Curie)
Nuclear transformations per unit of time
Amount of radioactivity of a nuclide
DID YOU KNOW?
Marie and Pierre Curie
Discovered Radium in 1898
Radiation Units and Terms
We are all exposed to radiation everyday!
Naturally-occurring in our soil, air, and water
Even our bodies contain natural radioactivity!
Background Radiation
Average US resident receives about 600 millirem per year from naturally-
occurring and man-made sources of radiation
Equivalent to ~20 chest x-ray procedures
Half comes from naturally-occurring sources of radiation:
Largest contributor is Radon
Half is from man-made sources such as:
Computed Tomography (CT)
Nuclear Medicine
Background Radiation
Diagnostic Radiopharmaceuticals (Tc-99m, F-18, Tl-201, I-131, and I-125)
Used in Nuclear Medicine and at the Biomedical Research Imaging Center
Emit penetrating gamma rays
Remain in the subject after the study
Have short half-lives (so subject and others are not exposed for long periods)
Negligible radiation hazard from these individuals
No “special” precautions in caring for these individuals
Practice universal precautions
No restrictions on subject activities or contact with other people
Radioactive Materials
Radioactive Materials
Radionuclides used in clinical labs emit beta particles and gamma rays
Beta particles are not as penetrating as gamma rays or x-rays
Weak/moderate energy betas will not penetrate the skin
Keep radioactive materials from contaminating the skin and work areas
Contaminated skin may lead to ingestion/absorption and spread of material
Because radiation cannot be seen or felt, the radiation symbol (“tri-foil”) is used to alert you to its presence
Posting for containers of radioactive
material and rooms where radioactive
materials are stored or used
Posting for rooms or areas where
radiation-producing equipment is used
Signs and Labels
Although radiation can be of benefit, too much can be dangerous
Two types of ionizing radiation effects
Effects occurring given enough dose
Threshold effects such as cataracts and erythema
Effects with a higher chance of occurring as dose increases
“Chance” effects such as cancer, genetic mutations, and effects on the embryo/fetus
Radiation dose effects
Large-dose effects are well-documented and understood
Low-dose radiation effects are not so well understood
Radiation Risk Assessment
The important thing to remember is the perception of risk vs. the reality
Many think of radiation based upon what they have seen in the movies
This FICTION is their PERCEPTION
The reality is the risks from radiation are quite low
For example, the risk of getting cancer from 10 millirem of radiation is roughly equivalent to the chance of winning the lottery by buying only one ticket
Radiation Risk Assessment
It is also important to realize that standards and regulations for your job keep the chance of undesirable effects quite low
Workers of UNC are in general exposed to low doses of radiation
Risks from radiation exposure are comparable to risks from other “safe” professions
You may also be exposed to x-rays as a patient (not occupational)
Calculate your own dose and risk from medical exposure to x-rays at http://xrayrisk.com/.
Radiation Risk Assessment
UNC-Chapel Hill Department of Environment, Health & Safety Radiation Safety
Section
Acts as an “agent” for the Radiation Safety Committee
Manages the University’s radiation protection program
Obtain radiation safety information from the Radiation Safety Officer (RSO) at
919-962-5507
Click here for Radiation Safety’s website: UNC Radiation Safety
Radiation Protection at UNC
Radioactive materials used under a “broad medical license”
Issued by the Department of Health and Human Services
North Carolina Radiation Protection Section (NCRPS)Visit their website at: NC Radiation Protection
X-ray machines are licensed or registered with the NCRPS
Radiation Safety Committee
Oversees and approves ALL use of radioactive materials and radiation-producing
equipment
NCRPS "Notice to Employees" form
Contains important information
Posted where radiation sources are used
Radiation Protection at UNC
NC Regulations require we have an ALARA program
Ensures radiation exposures are maintained As Low As Reasonably Achievable
ALARA assumes any radiation dose, no matter how small, can have some adverse
effect
-Shoe store fluoroscopes such as this one
from the early 1900s were outlawed-
They are not ALARA!
Radiation Safety Practices - ALARA
Minimize radiation exposure by utilizing three basic principles:
Time, Distance and Shielding
Radiation Safety Practices - ALARA
Radioactive Spills:
Do not clean up unless trained in radiological response
Remember, small droplets may splash away from the spill
Contain running liquids with a paper towel or other absorbent material
Isolate the area and notify the Radiation Safety Officer
Monitor all persons involved in a spill for contamination
Basic Radiation Safety Procedures
NC Regulations For Protection Against Radiation
Dictate the amount of radiation a person may occupationally receive
15A NCAC 11 Annual Dose Limits for Monitored Radiation Workers:
Whole Body: 5,000 millirem
Skin/Extremities: 50,000 millirem
Lens of Eye: 15,000 milliremA worker is required to be monitored if likely to exceed 10% of the above limits
General public (non-radiation worker, this is you)
Allowed 100 millirem per year
-DID YOU KNOW?-
The first US dose limit set in 1957
was 300 millirem/week!
Dose Limits and Monitoring Requirements
RADIATION-PRODUCTING EQUIPMENT
External Exposure Only
Hazard present ONLY when equipment “ON”
Authorized operator present whenever equipment “ON”
Enter only those areas you are authorized and trained to enter
Rooms adequately shielded for protection
Avoid immediate work/use area if possible
ASK personnel in area and stay alert
Guidelines for Working Safely Around
Radiation Sources
RADIOACTIVE MATERIALS
External exposure and contamination hazards (both external and internal)
Hazard present when materials not shielded or contained
Research subjects may also be radioactive
Radioactive materials should be secured at all times
Look for warning labels (including radioactive waste)
ASK personnel in area and stay alert
Know procedures for contamination incidents & spills
Food & drink only in designated areas
Guidelines for Working Safely Around
Radiation Sources
Report unusual or unsafe conditions
involving sources of radiation to the
Radiation Safety Office immediately
Radiation Safety is available during normal
working hours at 919-962-5507
Radiation Safety can be reached after
normal working hours through Campus
Police at 919-962-6565 or 911 (from
campus/hospital phone)
Radioactive Materials licenses, x-ray registrations, regulations, inspection reports and exposure reports are available for review in the UNC Department of Environment,
Health and Safety, Radiation Safety Section
1120 Estes Drive Extension, CB# 1650
Important Contact Information