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12 Cards in this Set
- Front
- Back
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Radiation Oncology
Five possible modes of interaction of photons with matter: |
1. coherent scattering
2. photoelectric absorption 3. compton scattering 4. pair production 5. photo-nuclear disintegration |
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Radiation Oncology - Pharm
What two rays are predominately used int electromagnetic radiation? |
X-rays and gamma rays
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Radiation Oncology - Pharm
What are three long term effects of radiation? |
1. carcinogenicity
2. hereditary effects 3. teratogenic effects (dose to embryo) |
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Radiation Oncology - Pharm
How are gamma and x-rays produced? |
Gamma: decay of radioactive materials
X-ray: produced by electrical machines |
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Radiation Oncology - Pharm
What is the range of x-ray for diagnosis and therapy? |
Diagnosis: 10-200KV
Therapy: >200KV |
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Radiation Oncology - Pharm
What is the advantage of megavoltage radiation? |
Megavoltage radiation
1. skin sparing 2. increased depth dose 3. less side scatter and sharper beam edge 4. predominance of comptom interactions |
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Radiation Oncology - Pharm
What are three advantages of electron beam RT? |
Electron beam RT:
1. useful in skin and superficial lesions 2. uniform dose from surface to depth 3. dose falls off rapidly |
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Radiation Oncology - Pharm
What is the target of radiation? |
DNA
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Radiation Oncology - Pharm
What is the process of interaction of radiation with the body? |
Incident photon --> fast electron --> free radical --> chemical change --> biological effect
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Radiation Oncology - Pharm
What is the oxygen effect? |
Oxygen effect
The level of cell killing by photons is dependant on the cellular oxygen tension at the time of radiation Oxygen enhances the cell killing effect of radiation. |
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Radiation Oncology
What are the differences between the two radiation techniques: Brachytherapy & Teletherapy |
Brachytherapy: radiation device is placed very close to or within target tissue
Teletherapy: device is located at a distance from the patinet |
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Radiation Oncology
What is one benefit of have two strand breaks in DNA being far apart? |
Between those two breaks there is a bunch of base damage.
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