The document provides details about the acceptance testing and commissioning of a new TrueBeam linear accelerator installed at the facility. Some key details include: - The machine was installed in an existing bunker previously occupied by a Siemens Primus Plus with additional shielding added. - Acceptance testing verifies a small subset of beam data based on manufacturer guidelines to check specifications, while commissioning involves comprehensive beam measurements and treatment planning system configuration. - Beam data measurements included depth doses, profiles, output, symmetry, flatness, and other dosimetric parameters which were analyzed and entered into the treatment planning system. - Electron and photon beam energies and characteristics were evaluated to ensure they met tolerance limits. Other

1. Vineeth.C
CUAPRAD012
1

2. • Millenium 120 Leaf HDTM MLC
• PerfectPitch TM 6DoF Couch
• RGSC Gating
• aS1200 MV Imager
• Photon Energies :- 6,10,15 MV
& 6,10 MV FFF
• Electron Energies :-
6,9,12,15,18 MeV & 6,9 MeV
HDTSe
2

3. New TrueBeam machine is installed in the existing bunker of Siemens Primus Plus with a
maximum photon energy of 15 MV
according to AERB guidelines , though maximum energy remains the
same, additional shielding of 30 cm concrete was added on the
primary as well as secondary wall of area with maximum occupancy
3

4. The acceptance testing implies the verification process of the
machine based on manufacture’s guidelines for a very small subset of
beam data whereas commissioning is a process where a full set of
data is acquired that will be used for patient treatment
Manufacturers often provide guidelines and
tolerance limits for acceptance testing of a
machine through their acceptance testing
procedure
4

5. Energy
(MV)
6 10 15 6FFF 10FFF
Dmax(cm)
(±0.15)
1.60 2.4 2.9 1.50 2.34
PDD at
10cm (±1.0)
67.2 74.1 77.4 64.3 71.8
Min D.R
(MU/Min) 5 5 20 400 400
Max D.R
(MU/Min) 600 600 600 1400 2400
e- energy
MeV
6 9 12 15 18
Depth of
ionisation1
90% (cm,±0.1)
1.71 2.68 3.77 4.67 5.58
80% (cm,±0.07) 1.90 2.95 4.15 5.2 6.09
50% (cm,±0.1) 2.32 3.52 4.91 6.19 7.41
Radial &
Transverse
flatness2
±5% ±4.5% ±4.5% ±4.5% ±4.5%
1Depth of ionization applies to the 15 X15 cm2 applicator field size, using a water phantom at 100 SSD
2Flatness is defined as the maximum variation from the mean electron ionization delivered within the
central 80% FWHM region measured for 10x10 cm2 through 25 x 25 cm2 fields.
5

6. ▪ Varian procedure for isocenter verification “Isolock”
▪ MV images –
1. 63 different gantry/collimator angles
2. 13 different couch angles
▪ Central axis s-ray beam variation :-
the gantry and/or collimator positions – 0.5 mm
gantry,couch, and/or collimator positions – 0.75 mm
▪ EPID-based Winston Lutz (WL) test :- within 1 mm tolerance
6

7. ❑ Congruence between optical and radiation fields
Symmetric Fields
- 5x5 cm2 : 0.5mm
-10x10 cm2 : 1mm
-20x20 cm2 :1mm Tolerance Limits = 2mm
-30x30 cm2 :1mm
Asymmetric fields
- defined by over travel option of the collimator - 1mm
❑Overlapping between parallel opposed radiation fields
- defined by jaws for 10x10 cm2 Tolerance = 3mm
- defined by MLC for 10x10 cm2 0.5 mm
7

8. ▪ Satisfactory acceptance testing simply assures that the accelerator satisfies all
agreed-upon specifications and pertinent safety requirements
▪ Commissioning includes comprehensive measurements of dosimetric parameters
▪ also includes
- entry of beam data into a treatment planning system
- testing of its accuracy
- development of operational procedures
-training of all concerned with the operation of the accelerator
8

9. 9

10. i. PTW PinPoint® Chamber.
ii. Advanced Markus® Electron
Chamber
iii. PTW Farmer® Ionization
Chamber
iv. IBA CC13 Ionization
Chamber
v. IBA RAZOR™ Nano
Chamber
10

11. Dmax (cm)
6 MV 1.59
10 M V 2.42
15 MV 2.9
6 MV FFF 1.43
10 MV FFF 2.36
PHOTONS
11

12. 100×
Dmax −Dmin
Dmax +Dmin
12

13. SYMMETRY
The ratio between measured values for each pair of symmetrical points
(with respect to beam axis) for a range of field sizes and gantry orientations
must lie between .98 and 1.02 within the central 80% flattened beam area.
Field Size
(cm2)
6 MV 10 MV 15 MV
Flatness Symmetry Flatness Symmetry Flatness Symmetry
I P C P I P C P I P C P I P C P I P C P I P C P
05x05 104.3 104.2 100.2 100.3 103.8 104.1 100.2 100.3 103.8 104.3 100.5 100.4
10X10 105.0 105.3 100.4 100.6 104.8 105.1 100.2 100.5 104.2 104.5 100.5 100.5
20x20 104.3 104.4 100.4 100.6 103.5 103.2 100.4 100.6 103.4 103.5 100.7 100.6
30x30 104.2 104.1 100.5 100.9 103.6 103.7 100.5 100.5 104.2 103.9 100.7 100.4
40x40 105.1 105.0 100.6 100.8 104.0 103.6 100.7 100.6 104.3 104.4 100.6 100.5
Flatness for field sizes 5x5 cm2 to 30x30 cm2 : ± 3% & for field size >30x30 cm2: ± 5%
Symmetry = ±2% 13

14. 14

15. ❖ In-line, cross-line and diagonal beam profiles were measured for all available beam
energies for various recommended field sizes at Dmax, 5 cm, 10 cm, 20 cm and 30 cm
depth
❖ Beam profile data were first smoothened by median filter and then corrected for the
central axis discrepancy
❖ Beam profiles ware normalize to 100% at the central axis to their corresponding field
size
PENUMBRA
Penumbra for flat beam defined as the lateral separation of (20% - 80%) isodose on either
side of beam profile normalized to 100% at the central axis
F S
10 X 10 cm2
In Plane Cross Plane
Left (mm) Right (mm) Left (mm) Right (mm)
6X 5.55 5.57 5.93 6.01
10X 7.08 7.11 7.21 7.13
15X 7.21 7.29 7.5 7.4
15

16. 16

17. FFF beam analysis done
as per AERB Task Group
Recommendations
All Profiles Above 30 X 30 Field Size are
acquired in half profiles
17

18. Measured Diagonal Profiles Calculated Diagonal Profiles
18

19. 19

20. 20

21. According to TRS-398
TPR20,10 = 1.2661 × PDD20,10 − 0.0595
TIME
TPR20,10
6 MV 6 MV FFF 10 MV 10 MV
FFF 15 MV
10AM 0.6771 0.6381 0.7485 0.7157 0.7724
2PM 0.6754 0.6386 0.7482 0.7154 0.7730
6PM 0.6762 0.6386 0.7483 0.7144 0.7727
RAV 0.6762 0.6384 0.7483 0.7152 0.7727
21

22. ENERGY (MV) DLG (CM)
6 0.0470
10 0.0540
15 0.0560
6 FFF 0.0390
10 FFF 0.0490
22

23. Energy
With Couch
[MR(nC)]
Without Couch
[MR (nC) ]
Couch Trans.
Factor
Couch
Trans.
Factor
Thin Thick Thin Thick Thin Thick Avg
6MV 14.3 14.13 14.6 14.6 0.9795 0.9678 0.9736
10MV 15.98 15.84 16.22 16.22 0.9852 0.9766 0.9809
15MV 16.97 16.82 17.16 17.16 0.9889 0.9802 0.9846
6MV
FFF
13.7 13.52 14.01 14.01 0.9779 0.9650 0.9714
10MV
FFF
15.39 15.25 15.64 15.64 0.9840 0.9751 0.9795
23

24. X-Ray
contamination
24

25. Applicator
/ Field Size
(cm2)
Energy
(MeV)
Flatness (mm) Symmetry (%)
In Plane Cross Plane
In Plane Cross Plane
Lt Rt Lt Rt
10x10
6 8.5 8.4 9.2 8.7 100.42 100.73
9 7.2 6.9 7.2 7.4 100.7 100.62
12 7.6 8.0 7.3 7.7 101.7 100.93
15 7.6 7.6 7.3 7.8 100.96 100.95
18 7.6 7.6 7.5 7.9 100.67 100.72
25x25
6 9.0 8.2 8.9 8.7 101.37 100.52
9 6.8 6.2 6.6 6.6 101.6 100.82
12 6.9 6.3 6.6 6.6 101.53 100.4
15 7.2 6.8 6.7 6.8 101.41 100.97
18 7.5 7.2 6.9 6.8 100.91 100.82
Tolerance :- should not exceed 103% of the central axis value 25

26. Energy (MeV)
Penumbra (mm)
In Plane Cross Plane
Lt Rt Lt Rt
6 9.8 10.0 9.6 10.0
9 9.6 9.7 9.6 9.8
12 9.6 9.7 9.6 9.8
15 9.8 10.0 9.9 10.0
18 10.1 10.0 10.1 10.2
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27. 27

28. 28

29. Measured PDD data
is calculated and
fitted using EMC in
Eclipse Treatment
planning systrem
Open Field Depth Dose - 6 Mev
29

30. 30

31. Leakage Radiation Measurement
31

32. 32

33. Energy Avg. % Transmission Max. %
Transmission
X Jaw Y Jaw X Jaw Y Jaw
6 MV 0.41 0.45 0.60 0.70
10 MV 0.48 0.53 0.66 0.76
15 MV 0.5 0.57 0.7 0.83
6MV FFF 0.24 0.26 0.39 0.47
10MV
FFF 0.22 0.24 0.34 0.39
33

34. (a) Each beam limiting jaw (excluding MLC jaws) shall attenuate x-radiation such
that kerma rate due to transmitted radiation does not exceed 2% of the maximum
kerma rate measured along the central axis of the beam at NTD (normal treatment
distance) in a 10 x 10 cm radiation beam.
(b) For radiation fields of any size, the average kerma rate due to transmission
through the beam limiting jaws, including MLC jaws, shall not exceed 0.75% of the
maximum kerma rate on the central axis at NTD in a 10 x 10 cm radiation field.
34

35. Measurement:-
• SCD 100 cm at a depth of 5 cm in water phantom (RFA)
-Interleaf leakage measurements were performed separately for both banks
• CC13 ion chamber exactly placed between the two leaves.
• Projection of the leaf is properly verified and Meter readings are taken 10 cm
off-axis with fully closed MLC
• Increment of 1 cm taken in order to place the chamber exactly between the
two leaves and chamber moved to next consecutive position with the help of
myQA software.
- The same procedure is followed for intra leaf transmission except the
chamber is placed in center of leaf.
• Normalization - 10 × 10 cm2 open fields
• 600 MU/Min for FF beam & 1200 & 2400 MU/Min for 6 & 10 MV FFF beams
respectively
• 100 MU
ENERGY % TRANSMISSION
Avg. Max
6 MV 1.15 1.42
10 MV 1.42 1.71
15 MV 1.48 1.86
6 MV FFF 0.6 0.86
10 MV FFF 0.58 0.85
35

36. ▪ plane circular surface of radius 2 m
centered on and normal to the
radiation beam axis at NTD and
outside the area of the maximum
radiation beam area
▪ Tolerance :- a maximum of 0.2% and
an average of 0.1%
Energy % Transmission
Max Min
6 MV 0.0158 0.0107
10 MV 0.0163 0.0061
15 MV 0.0206 0.0069
6 MV FFF 0.0074 0.0044
10 MV FFF 0.0094 0.0025
Neutron :-max = 0.0131 % tol= 0.05 %
avg = 0.0126 % 0.02 % 36

37. at 1 m from the path
of the electrons
between electron
gun to target &
reference axis other
than patient plane
Energy % Transmission
Max Avg
6 MV 0.0219 0.0129
10 MV 0.017 0.0050
15 MV 0.0172 0.0074
6 MV FFF 0.0080 0.0043
10 MV FFF 0.0034 0.0020
37

38. 38

39. 39

40. 40

41. COV = (1/ X )*[(  (Xi- X)2 ) /(n-1)] ½
Set kV Output (mGy)
Avg X Σ(Xi-X)2 [Σ(Xi-X)2]/n-1 [[Σ(Xi-X)2]/n-1]1/2 COV
1 2 3
50 0.0615 0.0618 0.0613 0.0615 0.00000013 0.00000006 0.000251 0.00408
70 0.131 0.1313 0.1317 0.1313 0.00000024 0.00000012 0.000343 0.002613
80 0.173 0.1724 0.1722 0.1725 0.00000036 0.00000018 0.000422 0.002446
100 0.2618 0.2617 0.2613 0.2616 0.00000012 0.00000006 0.000247 0.000946
120 0.3599 0.3602 0.3584 0.3595 0.00000197 0.00000099 0.000994 0.002764
130 0.4106 0.4107 0.4116 0.411 0.0000006 0.0000003 0.000545 0.001327
140 0.4648 0.4654 0.4645 0.4649 0.00000021 0.00000021 0.000459 0.000987
41

42. Diameter of smallest hole clearly resolved
on monitor screen - 0.6mm or 0.023 inch
Recommended Performance standard that
must be resolved – 3 mm or 0.117 inch
Bar strip resolved on the monitor screen -
2.8 lp/mm
Recommended performance standard –
1.5 lp/mm must be resolved
42

43. Picket Fence Test
43

44. The picket fence test
consists of eight consecutive
leaf movements of 5 cm
wide rectangular fields
spaced at 5 cm intervals.
The field information is
contained in three test files,
which are run in sequence.
This test is used to verify the
leaf positioning accuracy
and also calibrates the
carriage positioning
accuracy
44

45. ▪ Commissioning of Varian TrueBeamTM Linear Accelerator was successfully carried
out. Removal flattening filter alters various commissioning associated parameter as
Field flatness, Field penumbra, Beam quality, Surface dose,Transmission factor, off
axis energy variation and Homogeneity need to be redefined for FFF beam other
than FF beam.
45

46. ▪ [1] Das, I.J., Cheng, C.W.,Watts, R.J., Ahnesjö, A.,
Gibbons, J., Li, X.A., Lowenstein, J., Mitra, R.K.,
Simon,W.E. and Zhu,T.C. (2008) Accelerator
Beam Data Commissioning Equipment and
Procedures: Report of the TG-106 of the Therapy
Physics Committee of the AAPM. Medical Physics,
35, 4186-4215.
http://dx.doi.org/10.1118/1.2969070
▪ [2] Nath, R., Biggs, P.J., Bova, F.J., Ling, C.C., Purdy,
J.A., van de Geijn, J. and Weinhous, M.S. (1994)
AAPM Code of Practice for Radiotherapy
accelerators: Report of AAPM Radiation Therapy
Task Group No. 45. Medical Physics, 21, 1093-
1121. (AAPM Report No. 47)
▪ [3] Sahani, G., Sharma, S.D., Sharma, P.K.,
Deshpande, D.D., Negi, P.S., Sathianarayanan,V.K.
and Rath, G.K. (2014) Acceptance Criteria for
Flattening Filter-Free Photon Beam from Standard
Medical Electron Linear Accelerator: AERB Task
Group Recommendations. Journal of Medical
Physics, 39, 206-211.
http://dx.doi.org/10.4103/0971-6203.144482
▪ [4] Khan, F.M. (2003) Physics of Radiation Therapy.
3rd Edition, Lippincott Williams & Wilkins.
▪ 5] Musolino, S.V. (2000) Absorbed Dose
Determination in External Beam Radiotherapy: An
International Code of Practice for Dosimetry
Based on Standards of Absorbed Dose to Water.
Health Physics, 81, 592-593. (IAEA TRS-398)
▪ [6] Boyer, A., Biggs, P., Galvin, J., Klein, E., LoSasso,
T., Low, D., Mah, K. and Yu, C. (2001) Basic
Applications of Multileaf Collimator: Report of
Task Group No. 50 Radiation Therapy Committee.
American Association of Physicists in Medicine
(AAPM TG-50, 10) (AAPM Report No. 72).
46

47. [7]Dosimetric Leaf Gap Measurement, Procedure
Recommended by Varian Medical System.
Eclipse 10 Inverse Planning Administration and
Physics rev. 6.1.1.
[8] Szpala, S., Cao, F. and Kohli, K. (2014) On Using
the Dosimetric Leaf Gap to Model the Rounded
Leaf Ends in VMAT/RapidArc Plans. Journal of
Applied Clinical Medical Physics, 15, 4484.
[9] Acceptance/quality assurance tests for
Medical linear accelerator, RPAD/ACC/QA/04
[10]Absorbed dose determination In external
Beam radiotherapy An International Code of
Practice for Dosimetry Based on Standards of
Absorbed Dose to Water -TRS 398
[11]IEC 60601-2-1 Particular requirements for the
basic safety and essential performance of
electron accelerators in range 1 MeV to 50 MeV
[12] IAEA TRS-381 The use of plane-parallel
ionization chambers in high-energy electron and
photon beams. An international code of practice
for dosimetry
[13] K. R.Winston and W. Lutz,“Linear accelerator
as a neurosurgical tool for
stereotactic radiosurgery,” Neurosurgery 22, 454–
464 (1988).
[14] Commissioning and Acceptance Testing of
the existing linear accelerator upgraded to
volumetric modulated arc therapy - Ekambaram
Varadharajana and Velayudham
Ramasubramanian
[15] Shende, R., et al. (2016) Commissioning of
TrueBeamTM Medical Linear Accelerator:
Quantitative and Qualitative Dosimetric Analysis
and Comparison of Flattening Filter (FF) and
Flattening Filter Free (FFF) Beam. International
Journal of Medical Physics, Clinical Engineering
and Radiation Oncology, 5, 51-69.
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