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39 Cards in this Set

  • Front
  • Back

What is the TD5/5 for 1/3 of the small bowel?

5000

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

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

What are the goals of a QA program?

Objectively and systematically monitor quality and appropriateness of patient care

What are the 3 main categories of an effective QA program?

1. Structure: staffing, equipment, facility


2. Process


3. Outcome

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

Give examples of human errors.

-Using wrong tattoo


-Bolus omitted


-Incorrect template used


-Wrong patient

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.



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...

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


What are the malignancies commonly treated using matching fields?

-4 field breast


-CSI


-lymphoma


-nasopharyngeal

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

What are reasons for TBI?

Prepare for BMT


Malginancies


-Leukemia


Genetic Disorders


-Fanconi's Anemia


-Thalassemia

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

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

What are various techniques used for TBI?

-Positioning: sitting, standing, lying down


-Energy: 6-10 MV


-Extended distance


-POP

What are the standard dose fractionation schemes used for TBI?

Single


-1000cGy/1 fx




Multiple


-1000cGy- 1200cGy/ 6 fxs/ 3 days

What are 2 things that you should not match fields over?

1. Known disease


2. Sensitive tissue

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



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

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.

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

What are the trade offs of decreasing the modulation for an IMRT plan?

-Fewer mus


-Decrease conformance

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

What are the trade-offs of a large number of segments for an IMRT plan?

-Increase treatment time


-Increase max dose gradient


-Increase confomity

Does step-and-shoot give more mus to the patient than sliding window?

No.


Step-and-shoot: 700 mu


Sliding window: 1200 mu

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

What does AAA stand for?

Analytical Anisotropic Algorithm

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

What are the 3 types of loading for HDR?

1. Manual Hot Loading


2. Manual Afterloading


3. Remote Afterloading (least dose to staff)

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

When would someone receive HBI?

When they have dispersed bone mets

When someone is receiving TBI what toxicity is both acute and late?

Interstitial pneumonitis

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

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

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

What organs have no volume effect for tolerance doses?

-Rectum


-Cauda equina

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

What is the TD5/5 for the bladder?

6500