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ARRT Review
Radiation Safety Part 8 - Direct vs Indirect Effects
Question | Answer |
---|---|
Will direct or indirect effects occur to master molecule? | Direct (to the DNA or RNA) |
Will direct or indirect effects occur to a water molecule? | Indirect |
Will direct or indirect effects create Radiolysis? | Indirect |
Will direct or indirect effects create a free radical? | Indirect |
Will direct or indirect effects occur to routine X-ray exams? | Indirect |
Will direct or indirect effects occur with higher LET? | Direct |
Will direct or indirect effects occur with lower LET? | Indirect |
Can some direct damage be repaired? | yes, but it still be cause latent damage such as cancer, abnormal functions |
A point mutation would be caused by which type of interaction? | indirect |
A double strand mutation would be caused by which type of interaction? | Direct, high LET |
What are two types of particulate radiation? | Alpha and Beta |
What are two types of electromagnetic radiations? | X-ray photons and gamma |
There is approximately ___% of DNA in the body | 1 |
Why will indirect effects be the most likely result from an xray interaction? | water is the most abundant part of the cell. Water is the primary part of the indirect affect. |
Ionization of water cause what chemical in the water? | Hydrogen Perioxide |
Free radicals contain an unstable ____________ shell electron | outer |
Will a free radical or hydrogen peroxide be created by direct interactions? | no, direct hits are to the DNA molecule itself and therefore no water molecule was affected |
What causes sublethal indirect damage hits to be able to be repaired? | Nutrients and protein in the repair enzymes. Need oxygen for repairs. |
Typical x-ray exam response is "nothing" | true... will not see immediate or short term effects. There MAY be long term effects such as cancer or genetics but that is very unlikely with low LET radiation like xray |
Direct hits will occur mostly with which type of combination: 1) High LET/High SI or 2) Low LET/Low SI | High LET/High SI |
Indirect hits will occur mostly with which type of combination: 1) High LET/High SI or 2) Low LET/Low SI | Low LET/Low SI |
How are SI and LET related? | directly |
What is SI | specific ionization. Pairs of ions that are transferred to tissue. The more pairs, more dense the energy is transferred, but shorter the distance it travels = more damage. Higher SI= Higher LET. Like a Tornado - concentrates damage in a small/short area. |
Example of low SI | x-ray photon. Very sparse transfer of ions into tissue, travels farther - like a hurricane and distributes the damage |
High RBE, High SI, High LET is an example of what radiation? | Alpha ( quality factor of 20) |
Low RBE, Low SI, Low LET is an example of what radiation? | X-ray (quality factor of 1) - this is what is multiplied with absorbed dose from dosimeter to get your equivalent dose on your dosimetry report |
OER ratio of 3 would be what type of energy? | Low LET, X-ray photon. OER measures the sensitivity of the tissue to oxygen. 3 indicates it is sensitive so it has to do with an interaction and xrays interact indirectly to create an effect |
OER ratio of 1 would be what type of energy? | Alpha or high LET. 1 means it is NOT sensitive from oxygenated tissue. |
How are QF and damage related? | directly. Higher the QF, more damage. Alpha is 20 and creates more damage |
How are RBE and OER related? | inversely. A low RBE for xray, will equate to a higher number for OER for xray. (Xray: RBE 1, OER 3) |