18/04/23 radiation safety - level 5 1

Radiation safetyRadiation safetylevel 5level 5

Frits Pleiter

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ContentsContents

atomic and nuclear physics (1) interaction with matter (3)

o sources and x-ray equipment (2)o shielding (3)o detection (4)o radiobiology (6)

• objective risk of radiation (6)• subjective risk acceptation (6)

quantities and units (5) regulations (7)

o practical health physics (8 - 10)o waste (11)

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Sources and x-ray equipmentSources and x-ray equipmentdiscovery of radioactivitydiscovery of radioactivity

Henri Becquerel

In 1896 Henri Becquerel was experimenting with a uranium salt. At the end of the day, he used to put the uranium salt in a cupboard, next to some photographic material wrapped in brown paper.

On a day he noticed that the photographic material had been exposed at a spot close to the uranium salt.

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Sources and x-ray equipmentSources and x-ray equipmentdefinition of a sealed sourcedefinition of a sealed source

radioactive substances that are•either embedded in or affixed to solid carrier material•or enclosed by surrounding material

in such a way that the carrier material or the enclosure offerssufficient resistance to prevent, under normal conditions of use,any dispersion of the radioactive substances

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Sources and x-ray equipmentSources and x-ray equipmentapplications of sealed sourcesapplications of sealed sources

measurements or investigationswelds in pipelines 192Ir, 60Co 1 - 100 TBqthickness of steel 137Cs, 241Am 10 GBqthickness of cigarettes 90Sr / 90Y 40 MBq - 40

GBqfilling heights 137Cs, 60Co 1 - 10 GBq

chemical analysisx-ray fluorescence 241Am, 57Co 40 MBq - 40 GBqgas chromatography 63Ni 400 MBq

medical applicationsbrachytherapy 90Sr / 90Y, 125I 2 MBqbrachytherapy 137Cs, 192Ir 50 - 500 MBq

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Sources and x-ray equipmentSources and x-ray equipmentISO 2919ISO 2919

sealed sources may be tested for the following 5 properties1.temperature and thermic shock2.pressure3.mechanical shock4.vibration5.puncture

classification runs from 1 (not tested) till 6 (most stringent test)gas chromatography 63Ni C32211industrial radiography 192Ir C43313

source with code C11111 has not been tested, but may be used

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Sources and x-ray equipmentSources and x-ray equipmentapplications of open sourcesapplications of open sources

(bio)chemical analysislabelling 3H, 14C, 32P, 125I 1 MBq - 10 GBq

medical diagnosticsbone, heart 99mTc 500 MBqlungs 83Kr 600 MBqthyroid 123I 20 MBqtumor 111In 100 - 200 MBqPET 11C, 13N, 15O 500 MBq

medical therapyhyperactive thyroid 131I 100 MBq - 1

GBqthyroid tumor 131I 2 - 6 GBq

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Sources and x-ray equipmentSources and x-ray equipmentapplications of open sourcesapplications of open sources

angioscan using 99mTccross-sections through the heartleft: septumright: wall of left atrium and ventriclebottom: apexdark spot at the bottom points to a bad blood circulation in the

apex

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Sources and x-ray equipmentSources and x-ray equipmentdiscovery of X-raysdiscovery of X-rays

Wilhelm Conrad Röntgen

In 1895 Wilhelm Conrad Röntgen discoverd a magic radiationthat could penetrate solid objects. He called them x-rays, sincethey were a real mystery to him.

If the emerging x-rays hit photographicmaterial, a picture could be made ofthe inside such as the bones of a handor the contents of a suitcase.

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Sources and x-ray equipmentSources and x-ray equipmentx-ray x-ray tubetube

negative cathodepositive anode

electron accelerationelectron deceleration (a lot of) heat

bremsstrahlungcharacteristic x-ray radiation

dose rate > 10 Gy/s possible !scattered radiation intensity is about a factor of 1000 smaller

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Sources and x-ray equipmentSources and x-ray equipmentx-ray x-ray spectrumspectrum

a) bremsstrahlungb) characteristic x-ray radiationc) radiation emerging from the tubed) radiation after extra filtering

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Sources and x-ray equipmentSources and x-ray equipmentx-ray x-ray spectrumspectrum

intensity of bremsstrahlung increases with:increasing anode voltageincreasing anode currentincreasing Z-value of anode materialdecreasing filter thickness

intensity of characteristic x-ray radiation increases with:increasing anode voltageincreasing anode currentdecreasing filter thickness

energy of bremsstrahlung increases with:increasing anode voltage

energy of characteristic x-ray radiation increases with:increasing Z-value of anode material

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Sources and x-ray equipmentSources and x-ray equipmentapplications of X-raysapplications of X-rays

bitewing

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Sources and x-ray equipmentSources and x-ray equipmentapplications of x-raysapplications of x-rays

CT-scan

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Sources and x-ray equipmentSources and x-ray equipmentexamples of x-ray equipmentexamples of x-ray equipment

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Sources and x-ray equipmentSources and x-ray equipmentneutronsneutrons

neutron = neutral particleinteraction with atomic nucleimaximum energy transfer in collision of particles with equal masses

good shielding material:paraffin H2-Cwater H2-Oconcrete chemically bound crystal water

bad shielding material:lead

leave safety measures to a real expert

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Sources and x-ray equipmentSources and x-ray equipmentNORMNORM

NORM = naturally occuring radioactive materials

examples:uranium + daughtersthorium + daughterspotassium

sometimes everywhere (radon in dwellings)sometimes very large amounts with very low concentrationsometimes subject to Decree Radiation Protection

oil and gass industry produce 210Pb containing waste