Basic Radiation ProtectionMae Minguillo

Radiation Protection

is a term applied to concept, requirements, technologies and operation related to a protection of the people against harmful effects of ionizing radiation.

Radiation

Energy emitted and transfer through space.

Types of Radiation

Primary Radiation most intense therefore most hazardous and most difficult to

shield.

Scattered Radiation inevitable in diagnostic radiology and is a direct result of the Compton effect.

Leakage Radiationradiation emitted from the x-ray tube housing assembly in all direction other that of the useful beam.

Cardinal Principles of Radiation Protection

Time Distance Shielding

System of Radiation Protection

Justification of Practicesany exposure procedures sufficient benefit to offset the radiation harm that it might cause.

BENEFIT

RISK

As Low As Reasonably Achievable

refers to the continual application of the optimization principle in the day-to-day practice, i.e., while assuring adequate diagnostic image quality.

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Optimization of Protection

Optimization includes the criterion: doses should be “as low as reasonably achievable” assuming image quality is adequate for diagnostic purposes.

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Limitation of Doses

The normal exposure of individuals shall be restricted so that neither the total effective dose nor the total equivalent dose to relevant organs or tissues.

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Biologic Effects of Radiation EffectsStochastic Effects / Probablistic Have no threshold level of radiation dose. The probability of the effects is proportional to dose.

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Non Stochastic Effect / Deterministic Have definite threshold levels of radiation dose. The probability of the effects is proportional to dose.

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Types of Exposure

Medical ExposureExposure incurred by patients:

by persons, other than those occupationally exposed, knowingly while voluntarily helping in the support and comfort of patients.

Gray(Gy) unit for RAD (Radiation Absorbed Dose) - most often used when one is describing the quantity or radiation received by patient.

0.5mSv(50mrem)

Occupational Exposureall exposures of worker incurred:

exposures from practices or sources exempted by the standards.

Rem(Sv) unit for occupational radiation exposure - used to express the quantity of radiation received by radiation workers and populations.

50msv(5mrem) *whole body effective dose equivalent

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Exposure of the Members of the Publicexposed incurred by public:

members of public in radiation source.

General Public 1mSv(100mrem) *frequent exposure

50mSv(500mrem) *infrequent exposure

Radiation Measurements and Monitoring

Radiation Monitoring Personnel Monitoring for individual radiation workers.in form of radiation badges.worn on the person of all workers.allow estimation of individual doses.

Personal Monitoring Devices

Film Badge Optically Stimulated Luminescence (OSL) Pocket Ionization Chamber Self reading Non-self reading Thermoluminescence Dosimeter (TLD)

Workplace Monitoringfor entire workplace and radiation room.usually require some forms of radiation detectors.integrated for workspace.allow estimation of exposure levels in the environment.

Design in Radiation Facilities

Controlled Areaspreventing or limiting the extent of potential exposures.should be label appropriately and should have restricted area.

Supervised Area usually located at periphery of the hospital complex. whenever possible the area around the therapy machine should be design as a controlled (including roofs in the machine)mazes should be design whenever possible as they reduce need for a heavy shielded door.

the controlled console should be provided w/ a watch on the patient at all times.

Ducts for electrical material should always run through a secondary barrier at an angle through it.

warning sign, lights and audible alarm should be provided.

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