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39 Cards in this Set
- Front
- Back
What is the TD5/5 for 1/3 of the small bowel? |
5000 |
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What is the 5 steps involved in installing a new linear accelerator? |
1. Acceptance testing 2. Preliminary Rad Survey 3. Commissioning 4. Staff Education 5. Ongoing QA checks |
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What are random and systematic errors? |
Random: results from variations in daily set-ups Systematic: variations in the translation of the treatment from the planning stage to the treatment unit. Remains constant |
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What are the goals of a QA program? |
Objectively and systematically monitor quality and appropriateness of patient care |
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What are the 3 main categories of an effective QA program? |
1. Structure: staffing, equipment, facility 2. Process 3. Outcome |
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What are some mechanical and dosimetric requirements when commissioning a treatment machine? |
Mechanical: jaw symmetry, treatment couch, gantry rotation, ODI, digital readouts Dosimetric: exposure rate, light beam with x-ray beam, field flatness, monitor chambers |
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Give examples of human errors. |
-Using wrong tattoo -Bolus omitted -Incorrect template used -Wrong patient |
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What are interfractional and intrafractional variation? |
Interfractional: variation in position of target volume between one treatment and the next. Intrafractional: variation in position of target volume during treatment. |
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What is the purpose of a QA committee? List 5 aspects of a technical variance that is assessed and documented. |
To review error that occur in the department, determine the circumstances that contributed to each error and make recommendations to policy to minimize further errors. 1. All stakeholders should be represented 2. Monthly meetings 3. Findings should be communicated to staff 4. Annual meetings should be held to assess overall trends and create report based on findings 5. Findings should be communicated to staff... |
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List the 5 aspects of a Safety Occurrence Report |
1. Nature of variance: the problem 2. Location of variance: where did it occur 3. Treatment site: what anatomy 4. Causative factors 5. Level of variance: level 1- not affected, level 2 - affected but can correct, level 3 - affected but can't correct
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What are the malignancies commonly treated using matching fields? |
-4 field breast -CSI -lymphoma -nasopharyngeal |
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What the the different techniques used to match adjacent and orthogonal fields? |
Tech. A: angle the gantry using TOA, eliminates over and under lap Tech. B: match fields at a depth, leave skin gap, cold on skin, hot beyond the depth Tech. C: half beam block both fields Tech D. use beam spoiler at edges to increase penumbra, feather the junction |
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What are reasons for TBI? |
Prepare for BMT Malginancies -Leukemia Genetic Disorders -Fanconi's Anemia -Thalassemia |
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What is the difference between allogeneic and autologous bone marrow transplants? |
Allogeneic BMT stem cells come from donor and autologous BMT stem cells come from patients own blood or BM |
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What are patient care issues related to TBI patients? |
-patients are immunosuppressed, sterile techniques -pre meds for nausea and vomiting -patient might need to rest between fields -have water and maybe a fan available for the patient |
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What are various techniques used for TBI? |
-Positioning: sitting, standing, lying down -Energy: 6-10 MV -Extended distance -POP |
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What are the standard dose fractionation schemes used for TBI? |
Single -1000cGy/1 fx Multiple -1000cGy- 1200cGy/ 6 fxs/ 3 days |
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What are 2 things that you should not match fields over? |
1. Known disease 2. Sensitive tissue |
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What happens to PDD, uniformity, penumbra and depth of Dmax when the SSD is increased? |
-PDD increases -Uniformity increases - Penumbra increases -Depth of Dmax decreases, shallower |
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What is GVHD? |
Graft vs Host Disease: immune response of donor T-lymphocytes against host's normal tissue. Acute: under 100 days post op Chronic: over 100 days post op |
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What are max and min dose objection? |
Max: penalty if any point in OAR receives greater than given value. Min: penalty if any point in target receives less than given value. |
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What are the trade offs of increasing the number of beams for an IMRT plan? |
-Irradiate large volume of tissue -Conform high dose to target |
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What are the trade offs of decreasing the modulation for an IMRT plan? |
-Fewer mus -Decrease conformance |
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What are the trade-offs of small area segments for an IMRT plan? |
-Increased resolution -Increase max dose gradient -Uncertain dosimetry -Intra-fraction motion more critical |
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What are the trade-offs of a large number of segments for an IMRT plan? |
-Increase treatment time -Increase max dose gradient -Increase confomity |
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Does step-and-shoot give more mus to the patient than sliding window? |
No. Step-and-shoot: 700 mu Sliding window: 1200 mu |
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Out of Monte Carlo, correction based and model based which one is most complex? Uses look up tables? Uses fundamental laws of physics? |
Most complex: Monte Carlo Look up tables: Correction based Laws of physics: Monte Carlo |
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What does AAA stand for? |
Analytical Anisotropic Algorithm |
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What cancers are treated with interstitial HDR? Intracavitary HDR? Surface mold HDR? |
Interstitial: prostate, some gynea, breast, H&N Intracavitary: bronchus, esophagus, bile duct Surface molds: superficial lesions |
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What are the 3 types of loading for HDR? |
1. Manual Hot Loading 2. Manual Afterloading 3. Remote Afterloading (least dose to staff) |
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What are characteristics of 192-Ir that make it a good source for HDR? |
-High specificity: small source size with high activity -3 month half life -Average energy ~ 360 KeV |
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When would someone receive HBI? |
When they have dispersed bone mets |
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When someone is receiving TBI what toxicity is both acute and late? |
Interstitial pneumonitis |
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What is the TD5/5 for 3/3, 2/3 and 1/3 of the heart? |
3/3: 4000 2/3: 4500 1/3: 6000 |
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What is the TD5/5 for 3/3, 2/3 and 1/3 of the esophagus? |
3/3: 5500 2/3: 5800 1/3: 6000 |
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What is the TD5/5 for 3/3, 2/3 and 1/3 of the kidney? |
3/3: 2300 2/3: 3000 1/3: 5000 |
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What organs have no volume effect for tolerance doses? |
-Rectum -Cauda equina |
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What is the TD5/5 for 3/3, 2/3 and 1/3 of the liver? |
3/3: 3000 2/3: 3500 1/3: 5000 |
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What is the TD5/5 for the bladder? |
6500 |