Radiation protection dosimetry Anne Laure Lebacq, Olivier Van Hoey - - PowerPoint PPT Presentation

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Aug 24, 2022 248 likes •388 views

Radiation protection dosimetry Anne Laure Lebacq, Olivier Van Hoey Belgian Nuclear Research Centre SCKCEN Photo by SCKCEN Why do we need dosimetry? Radiation induces health effects Photo by Wikipedia / CC BY SA Photo by

SLIDE 1

Photo by SCK•CEN

Radiation protection dosimetry

Anne Laure Lebacq, Olivier Van Hoey Belgian Nuclear Research Centre SCK•CEN

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Why do we need dosimetry?

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Radiation induces health effects

Skin burns Cataract Cancer

Photo by www.oramed-fp7.eu Photo by Wikipedia / CC BY SA

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2 types of health effects

Deterministic effects Stochastic effects E.g. burns, cataract, hair loss, organ failure E.g. cancer, inheritable effects Only above threshold dose No threshold dose Severity increases with dose above threshold Probability increases with dose Appear typically immediately Appear typically after several decades

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3 pillars of radiation protection

Justification
ALARA = As Low As Reasonably Achievable
Dose limits

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How can we express and measure the dose?

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How much energy is deposited in the body?

Organ absorbed dose DT Energy deposited per unit of mass for tissue T Expressed in Gy (gray) = J/kg

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How harmful is the radiation?

Radiation weighting factor wR Expresses how much more damaging radiation type R is with respect to photons for the same organ absorbed dose Dimensionless

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How harmful is the radiation?

Radiation type R Radiation weighting factor wR Photons, electrons, muons 1 Protons, charged pions 2 Alpha’s, heavier nuclei 20 Neutrons wR(E)

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How sensitive are the affected tissues?

Tissue weighting factor wT Expresses which fraction of stochastic effects occurs in tissue T for a uniform whole body radiation exposure Dimensionless

Tissue T Tissue weighting factor wT Red bone marrow, colon, lung, stomach, breast, remaining 0.12 Gonads 0.08 Bladder, oesophagus, liver, thyroid 0.04 Bone surface, brain, salivary glands, skin 0.01

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Quantification of deterministic effects

Organ equivalent dose HT 𝐼" = $ 𝑥&𝐸",&

Expressed in Sv (sievert) = J/kg

Photo by SCK•CEN Photo by www.oramed-fp7.eu

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Quantification of stochastic effects

Effective dose E 𝐹 = $ 𝑥"𝐼"

Expressed in Sv (sievert) = J/kg ~ 5% extra cancer risk per Sv

Photo by SCK•CEN Photo by SCK•CEN Photo by SCK•CEN

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