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Energy that comes from a source and travels through some material or through space.
- High energy radiation capable of producing ionization in substances through which it passes.
- Ionization radiation can be harmful to humans.
- X-ray (AKA): phantom, EM energy quantum, & balance of energy.
- The radiographer must protect all persons who come in contact with radiation.
- Are form of electromagnetic radiation.
- Travel at the speed of light.
- No mass.
- No charge.
- Purpose is to reduce exposure to staff, patients, & public as much as possible while maintaining image quality.
- ALARA: As Low As Reasonably Achievable
- Cardinal Priniciples of Radation Protection: Time, Distance, and Shielding.
As Low As Reasonably Achievable
Cardinal Principles of Radiation Protection
- Time: minimize time equals less dose.
- Distance: Maximize distance to prevent scatter from patient.
- Shielding: Always shield.
- Refers to length of time an individual is exposed to ionizing radiation.
- Minimize time. Less time equals less dose.
- Time has a direct relationship to dose.
- Increase distance reduces dose according to Inverse Square Law.
- Maximize distance.
- Primary source of occupational exposure is scatter from patient increases your distance from patient.
- Use when it it will not obscure diagnostic information.
- Shielding devices: Lead aprons, thyroid shield, lead glasses, shielding helps to decrease patient dose.
Specific Area Shielding
- Ex. Gonadal Shielding.
- Use on patients of reproductive age.
- Use when gonads are in or near the useful beam (withing 5cm).
- Use when it's use will not comprise required diagnostic information.
Personnel Monitoring Devices
- Must be worn at all times!
- Dose measuring devices that measure or detect radiation exposure from X-rays.
- Measure dose & energy of radiation.
- Must be worn on collar, outside of apron.
- Additional personnel monitoring device is worn by pregnant women.
Protecting the Radiographer
- Cardinal Rules of Radiation Protection
- Radiation monitoring device is Optically Stimulated Luminescence (OSL)
- Consists of a strip of Al Oxide, a Cu Filter, a tin filter, & an imaging filter.
How the OSL works
Al oxide is exposed to a laser light which is stimulated after use, causing it to become luminescent in proportion of the amount of radiation exposure which determines the occupational worke's exposure.
Protecting the patient
- Cardinal Rules of Radiation
- Beam restricting devices (focus on the area with the calumniator.
- Technical factor selection.
- Filtration aluminum absorbs low energy photon (xrays) to improve patient dose. Low atamic number absorbs low photons to allow only high photons to go through patient.
kVp and mAs
- High kVp and low mAs equals to low PT dose.
- Also known as technique.
Ten commandments of Radiation Protection
- 1. Understand & Apply Cardinal Principles of radiation control.
- 2. Do not allow familiarity to result in false security.
- 3. Never stand in primary beam.
- 4. Always wear protective apparel when not behind a protective banner.
- 5. Always wear radiation monitor & position it outside lead and collar.
- 6. Never hold a PT. Have parents or friends hold patients.
- 7. Persons holding patients must always wear protective apron & gloves if possible.
- 8. Use gonadal shielding on all people of child bearing age when such use will not interfere with exam.
- 9. Avoid X-raying pregnant patients.
- 10. Always collimate to smallest field size appropriate for exam.
- Exposure: Roentgen (R)
- Absorbed dose: Rad/ Gray (Gy)
- Dose equivalent: Rem/ Sievert (Sv)
- Kerma: Joule/kg Gray (Gy)
- Exposure in air:
- Roentgen (R): is exposure in air.
- Columb/Kilogram (C/kg): New term replacing Roentgen.
- Old term: Rad - Radiation Absorbed Dose
- New term: Gray (Gy)
- Occupational exposure
- Old term: Rem - Radiation Equivalent Man
- New term: Sievert (Sv)
Optically Stimulated Luminescence
- Kinetic Energy Released in Matter
- Joule/kg Gray (Gy) - absorbed dose.
- For diagnostic x-rays, air Kerma is same as abosorbed dose delivered to air that is measured in Grays (Gy).
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