Comparison on Proton Therapy
Institutional Data
Paige Summers, MS
This project is supported by the Federal Share of program
income earned by Massachusetts General Hospital on C06
CA059267, Proton Therapy Research and Treatment
Center and by grants CA10953 and CA81647 (NCI, DHHS).
Proton Centers Reviewed: Fast Facts
• 8 US proton centers reviewed (one twice)
• Synchrotrons and cyclotrons
• Scattered & uniform scanning
• Fixed, incline and rotating gantry beam lines
• XiO, Eclipse and Odyssey planning systems
• Philips, Siemens, and GE CT scanners
• Treating pediatric and adult patients
Output Results
• Criteria: ±5%
• Dosimetry system
intercomparison performed
with Institution, RPC ion
chambers and electrometers
• Measured for reference field
• Patient field comparisons
made with ion chambers and
ion chamber arrays (cross
calibrated same day)
Institution
Output RPC/Inst.
A
0.99 - 1.02
B
1.00 - 1.02
C
0.95 - 1.02
D
0.96 - 1.02
E
0.97 - 1.00
F
0.95 - 1.01
G
0.98 - 1.01
H
0.97 - 1.02
I
0.96 - 1.00
CT Scanner Recommendations
Institution
RLSP RPC/Inst.
A
0.88 - 1.01
B
0.99 - 1.04
C
0.79 - 1.02
D
1.00 - 1.04
E
0.96 - 1.08
F
0.97 - 1.23
G
0.97 - 1.13
H
0.96 - 1.17
I
0.79 - 1.02
Phantom Results
Institution
Phantom:
RPC/Inst
DTA [mm]
A
0.95 – 0.96
1–3
B
0.96 – 0.97
1–4
C
0.95 – 0.97
0–2
D
0.96 – 0.97
1–4
E
0.94
0–4
F
0.95 – 0.96
0–3
G
0.94 – 0.96
1–3
H
In progress
-
I
In progress
-
• RPC/Inst ratio measured
using TLD (± 7%)
• DTA measured using
Gafchromic film (±4 mm)
Phantom Results
RPC Proton Site Visits
• After visits, RPC generates comprehensive site visit
report – sent to institution with recommendations
RPC Recommendations
Treatment On Board
CTN-RSP CT Scaling
Planning Imaging
8
1
2
3
QA
Total
(9 visits)
39
53
• QA recs: range uniformity, output, lateral penumbra,
distal penumbra, QA procedures, equipment
Proton TLD Results
1.2
1.15
RPC/Inst
1.1
1.05
1
0.95
0.9
12/31/2001
1/1/2006
12/31/2002
1/1/2007
12/31/2003
1/1/2008
12/30/2004
1/1/2009
12/31/2005
1/1/2010
Date
12/31/2006
1/1/2011
12/31/2007
1/1/2012
12/30/2008
1/1/2013
Questions?
??
Other RPC Proton Activities
• NIST/proton ion chamber
intercomparison
Cylindrical
chambers
• 9 institutions & NIST participated
• Calorimetry experiment planned
6/2012
• 56% of calcs <1% diff
Parallel plate
chambers
TRS-398
• 94% of calcs <2% diff
• Two meetings with AAPM proton
advisory group
• Focused scope of measurements,
rewrote proton guidelines for clinical
trials
Pelvis Phantom Results
1
2
TLD (left)
0.97
0.97
TLD (right)
0.96
DTA (bladder)
Institution
3
4
5
0.97
0.95
0.96
0.96
0.95
0.95
0.95
1 mm
1 mm
1 mm
1 mm
NA
DTA (rectum)
3 mm
3 mm
0 mm
2 mm
NA
DTA (left/right)
2/4 mm
2/4 mm
2/1 mm
7/3 mm
NA
Lung Phantom Results
Institution
1
2
TLD (sup)
0.99
0.98
TLD (inf)
1.00
1.00
Gamma (axial)
91%
82%
Gamma (coronal)
84%
86%
Gamma (sagital)
84%
87%
Ave. Gamma
86%
85%