Radiology 4. Biological Effects of Ionising Radiation & Risk Assessment Flashcards

1
Q

what are the types of radiation (4 types)?

A

Alpha particle (2 protons/2 neutrons)

Beta particle (electron)

Gamma ray (electromagnetic radiation)

X-Rays

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2
Q

what happens to atoms when radiation passes through matter?

A

they are ionised along its path

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3
Q

how can radiation directly effect DNA?

A

radiation interacts with the atoms of a DNA molecule or another important part of the cell

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4
Q

how can radiation INDIRECTLY affect DNA?

A

Radiation interacts with water in the cell, producing free radicals which can cause damage

free radicals are unstable, highly reactive molecules

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5
Q

what happens to a single strand break in DNA when radiation affects it?

A

Single stranded breaks can usually be repaired

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6
Q

What happens to double stranded dna breaks when hit with radiation?

A

they are more difficult to repair than single stranded breaks. If the repair is faulty then this can lead to mutations which can affect cell function

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7
Q

what factors is the radiosensitivity of tissues dependent on? (2 factors)

A

the function of cells that make up the tissues

if the cells are actively dividing

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8
Q

what are the highest radiosensitive tissues?

A

bone barrow, lymphoid tissues, GI, gonads, embryonics

(the higher the cell division rate, the greater the sensitivity)

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9
Q

what is the least radiosensitive tissues?

A

CNS, Bone and Cartilage, connective tissue

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10
Q

what is the absorbed dose and its units?

A

Measures the energy deposited by radiation

Units - Grays (Gy)

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11
Q

what are the effects of radiation during pregnancy?

A

Radiation exposure could damage/kill enough of the cells for embryo to undergo resorption (kills itself)

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12
Q

Do precautions need to be taken for pregnant patients?

A

Pregnancy does not need to be taken into account for dental x-rays because the dose to the foetus is so low

the x-ray beam should not be directed towards the patient’s abdomen however.

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