Radiation Safety Bone Densitometer
Outline I. State Regulations II. Fundamentals of Radiation Safety III. IV. i. Characteristics of x-ray radiation ii. Units of radiation dose iii. Biological effects iv. Hazards of excessive radiation exposure Radiation Detection i. Use of personnel monitoring devices ii. Use of radiation monitoring instruments Users Guide and Standard Operating Procedures
I. State Regulations Michigan Department of Licensing and Regulatory Affairs, Radiation Safety Section Postings 1. Notice to Employees 2. Radiation Safety Rules located in Foust 104 and http://www.michigan.gov/lara/0,4601,7-154- 61256_11407_35791-313217--,00.html 3. Radiation Machine Registration Certificate + Tag 4. Standard Operating Procedures 5. Notice of Violation (at least 5 days) 6. Door signage (restricted area, in use sign, radiation symbol, emergency contacts)
Radiation = Energy radiated through space Ionizing Radiation = Enough energy to strip electrons from the orbitals of atoms Particulate (alpha, beta, neutron particles) Wave (gamma rays, X-rays) Nonionizing Radiation = Lower energy and frequency ultraviolet, infrared, microwaves, radio waves, electric power, etc.
Universal symbol for ionizing radiation
Ionizing Radiation -2 forms A. Electron tube generated (bone densitometer) radiation only when instrument is turned on B. Decay of an atom (uranium, plutonium) can t turn it off referred to as isotopes, radioisotopes, radionuclides sealed vs. unsealed sources
Door sign language for use of radioisotopes Door sign language for electron tube generated X- rays
II. Fundamentals of Radiation Safety i. Characteristics of x-ray radiation Exposure can be minimized through the use of time, distance and shielding (cannot become contaminated!) Time Minimize the time spent around a source of radiation Distance Maximize the distance from a source of radiation (Inverse Square Law) Shielding Use shielding wherever it is necessary to reduce or eliminate exposure
II. Fundamentals of Radiation Safety ii. Units of radiation dose A unit of dose equivalent = rem Allowed dose for the general public 100 mrem in any one year Allowed dose for a radiation worker 5000 mrem per year whole body 50,000 mrem per year extremities and skin ALARA Policy = Keep all employees exposure to radiation As Low As Reasonably Achievable
For reference, 360 mrem/year is the average annual whole body dose to U. S. population (cosmic, terrestrial, self radiation)
+ 280 mrem/year if you smoke a pack of cigarettes a day
+ 10 mrem per Dental X-ray
0.3 mr/hr at 91.4 cm from the bone densitometer unit Review p. 26-29 of Safety Information and Technical Specifications
II. Fundamentals of Radiation Safety iii. Biological effects Stochastic Effects = severity of the effect does not depend on dose (cancers, genetic effects) Non-Stochastic Effects = severity of these effects depends on the dose Short term = if fingers or hands come in contact with an X-ray diffraction beam, reddening and blistering of the skin will likely appear within a few hours
II. Fundamentals of Radiation Safety iv. Hazards of excessive radiation exposure
III. Radiation Detection i. Use of personnel monitoring devices The following two basic types of dosimeters are available: Whole body - These dosimeters are clipped on the person's clothing somewhere between the waist and neck. Extremity - These dosimeters are worn as a ring on a finger of the hand that is likely to receive the most exposure. Annual reports are sent out in Spring. A room dosimeter is located in the room 24/7. (Personnel dosimeters changed monthly; room dosimeters changed quarterly.) NOTE: Effective September 2013, personal radiation dosimeters are not required for operators of the bone densitometer.
III. Radiation Detection ii. Use of radiation monitoring instruments Occupational exposure to radiation from a bone densitometer unit results from one or both of the following two sources: 1. Scatter Radiation - required to be below 0.5 mr/hr at 5 cm from the protective cabinet 2. Leakage Radiation- required to be below 2.5 mr/hr at 5 cm from the tube housing We measure with an Ion Chamber Survey Meter.
IV. Users Guide and Standard Operating Procedures Equipment users must follow the requirements/standard operating procedures stipulated in the Manufacturer Users Guide Equipment users must know the appropriate response to warnings made in the event of a malfunction that may involve radiation exposure (know all indicator lights) Follow IRB approved procedure (pregnant patients, thyroid shields, number/length of scans, minor aged patients, etc.)
Questions? Radiation Safety Officer (989) 774-4189 Office Phone NOTE: Promptly report any condition that is unsafe, that may result in unnecessary exposure to radiation, and/or that may result in a violation of regulations!