This document summarizes the expectations and key learnings from a linear accelerator acceptance, commissioning, and annual QA training that occurred from September to November 2008. The training covered: 1. Fundamental concepts of linear accelerators, beam production, safety features, and the acceptance testing process. 2. Techniques for collecting beam data needed for commissioning, including measurements and data definitions. 3. Procedures for linear accelerator QA and other treatment machine QA on an annual basis. Key topics included the beamline components that produce photon and electron beams, characteristics of linear accelerator beams, the importance of acceptance testing and commissioning the machine properly, and techniques for annual QA tests.

1. Linear Accelerator Acceptance,
Commissioning and Annual QA
09/17/2008 – 11/14/2008
MENTORS: TIM WALDRON AND DR. JOE MODRICK
BY
VIBHA CHASWAL

2. Expectations
I Linear Accelerator Acceptance/Testing
a. Fundamental concepts of linear accelerators, beam
production and control
b. Medical Linear Accelerator Safety features
c. The acceptance testing process
II Radiotherapy Beam data Collection for Commissioning
a. Data Definitions
b. Measurement techniques and underlying principles
III Medical Radiotherapy Equipment QA
a. Linac QA
b. Other treatment machine QA (?)

3. Interpretation
Understand:
 Working of Linac, especially beam-line and beam
characteristics
 Importance or Acceptance Testing Procedure:
“that signature means you are stuck with the machine for next
10-15 years”
 Importance of Commissioning
“Quality of your treatment beams for life-time of the machine”
 Difference between both – effort
 Measurements for Commissioning
 Annual Constancy check of Linac - Procedures

4. 
 Lectures
 Data measurements
 Annual QA
 Reading
 Reading

5. Linac Beam Line
 Beam line: Electron gun>Wave-Guide>Bending Magnet> Target
> Flattening filter/Scattering foils > Monitoring chamber >
Collimation
Photon
Beam
Produc2on
mode
Electron
Beam
Produc2on
mode
Waveguid
e
Diode gun injector
IG
Waveguide
IIN
Diode gun injector
Bending Magnet
assembly
IB
IG = Gun current
I = Intrinsic current
IB = Beam Current
High Z
target
IG
IIN
Bending Magnet
assembly
IB
Primary foil
Flattening filter
Secondary foil
Patient treated at
CEIGRT at UIHC
RadOnc
Patient treated at
CEIGRT at UIHC
RadOnc

7. Beam Characteristics
 Energy: RF, BMI, Gun current
 Fluence: Gun Current, RF
 Flatness: Flattening filter
 Symmetry: Flattening filter

8. Acceptance: Verifying Specifications
 AAPM TG – 45
 Procedure starts at Installation, or even before while
making purchase agreement
 Importance
 Order in which tests should be performed
 Relative importance of some tests
 Procedures of preliminary calibration, isocenter
verification, end effect measurement
 Seemingly un-important tasks/tests that are absolutely
essential – (Oh! The electron mold kit doesn’t have the
frame for 25x25 cone)

9. Commissioning
 Much more effort!
 How much effort? – what is the minimum amount of
data you would require to commission a beam for
your CLINIC REQUIREMENTS.
 Beam characteristics important for treatment types
performed most commonly.
 Data measured.

10. AND ………..ANNUAL QA
 Oncor D with Sarah
 AAPM TG-40
 Techniques for Acceptance Procedures and
Commissioning data measurements
- 3D water tank and Linear array for profiles and
PDDs
- Gantry, Collimator and Table star-shots
- Mechanicals

11. 
 End effect
 Virtual Source for 12 meV and 15 MeV electrons on
Oncor B

12. 
Thank
you !!