Transcript CNAO - Indico

Update on FLUKA use at CNAO
Giuseppe Magro (PhD Student) and Andrea Mairani (HIT and CNAO)
Pavia, Dec 16, 2014
www.cnao.it
Outline
Daily support to the clinical activity
 (Recalculation of TP and/or TP-Verifications)
 Plan robustness
 Completion of partial treatments
RBE comparison: NIRS vs. CNAO in carbon ion
therapy
Eye treatments with active scanning
Towards “new” ion species
Page 2
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Plan robustness in scanned p-RT
 FLUKA used to investigate the impact of different sources of uncertainty
on proton beam ranges and dose distributions for typical scanned
proton patient treatment plans
 ±3% error in the CT grey levels (range uncertainty)
 maximum translation of 1 mm and maximum rotations of 1°(setup uncertainty)
 SFUD vs IMPT ( most critical!)
Page 3
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Completion of partial treatments (I)
 Treatment plans of carbon-ion radiotherapy are usually made on the
assumption that the beams are delivered instantaneously irrespective
to the dose delivery time as well as the interruption time
 The advanced therapeutic techniques such as a hypofractionation and a
respiratory gating usually require more time to deliver a fractioned dose than
conventional techniques
 “…If the fraction time prolongs to 30 min or longer, the biological
effectiveness is significantly influenced in carbon-ion radiotherapy,
especially with high-prescribed doses…” (Inaniwa et al, 2013)
 The purpose of this study is to investigate the effects of dosedelivery time structure on biological effectiveness in carbon-ion
radiotherapy on a macroscopic time-scale (i.e., days)
 Possible scenarios: machine failures, patient pain, …
Page 4
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Completion of partial treatments (II)
Possible choices
+ = linear sum of bio-doses
x = bio-sum of phys.-doses = “instantaneous” delivery
Page 5
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Completion of partial treatments (III)
 What’s on going?
 Dependence on the number and/or the orientation of the treatment fields,
exploring different solutions for the same patient
 More complex cases (highly disomogenous distributions, SFUD or IMPT
optimization dependence, ...)
 MCTP to optimize voxel by voxel the rest of the dose to be delivered
 N.B. :
 Dose prescription ultimately represents a clinical task under the
responsibility of the radiation oncologist, the presented analysis
intends to be a quantitative and objective way to assist present
and future clinical decisions
Page 6
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
RBE comparison: NIRS vs. CNAO (I)
 In carbon ion RT there is an urgent clinical need to develop objective tools
for the conversion of RBE-weighted doses based on different models
 Simple concept: less dose where LET is higher
 NIRS: uniform RBE weighted dose (plateau/proximal/middle/distal)
 CNAO: LEM I model  FLUKA interfaced with LEM I (Mairani et al, 2010)
 Clinically oriented method to compare NIRS-based and LEM-based GyE
systems, minimizing differences in physical dose distributions
between treatment plans
Phase I
“Reference” target volumes of cubic
and spherical shapes
NOW  Phase II
Confirm findings on LEM-based
prescription doses currently
adopted in clinical practice at
CNAO on real patients cases
Page 7
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
RBE comparison: NIRS vs. CNAO (II)
 Possible solution with FLUKA
 Modeling of the NIRS beamlines
 MC simulation of NIRS physical doses (clinical data)
 NIRS RBE-weighted dose according to LEM I  FLUKA interfaced with LEM I
Ridge filter 7 cm
300A,0380
Sub
monitor
WEPL 0.089
cm
Patient-specific
AIR
vacuum
Range shifter
(300A,0360)
WEPL 0.8543
cm
Main
monitor
WEPL 0.022
cm
Page 8
Pavia, Dec 16,
2014
Vacuum
window
Collimator Al
Update on FLUKA use at CNAO
Scatter
(300A,0370
WEPL 300A,033C)
www.cnao.it
RBE comparison: NIRS vs. CNAO (III)
 Patient-specific components
Page 9
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
RBE comparison: NIRS vs. CNAO (IV)
NIRS
FLUKA
Phys. Dose
Page 10
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
Eff. Dose
www.cnao.it
Eye-treatments with active scanning (I)
 CNAO is currently moving to activate a clinical trial for
ocular cancer treatments with scanned beams
 Fully active 3D – Dose Delivery System
Page 11
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (II)
 Eyeplan® (Goitein and Miller 1983, Sheen 1994)
 Geometrical approximation of the eye (no CT/MR info)
 Average eye density
 Beam lateral widening in tissues is neglected (no PB algorithm)
 Our aim: to use the existing image-based approach
(CT/MR/PET)  full TPS characterization
1H
Page 12
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (III)
 Siemens Syngo® TPS
 dosimetric accuracy demonstrated for volumes ranging from 20 cc
to 3000 cc (Molinelli et al 2013)
 general-purpose  not dedicated to ocular treatments and
cannot handle a patient-specific collimator
 most critical validated case is a 3x3x3 cc volume in a water
phantom at 25 cm in depth  far from a typical condition of an
ocular treatment
 Monte Carlo benchmarking (FLUKA)
 Homogeneous water cubes
 Real patients CT scans
Page 13
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (IV)
Page 14
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (V)
MC
Original TPS
TPS Corrected
-1.4 %
-13.6 %
-3.2 %
Page 15
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (VI)
The accuracy of MC simulations in reproducing experimental
results has been confirmed by relative deviations from measured
data lower than 3% for ALL cases analyzed
Page 16
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (VII)
Monte Carlo
Treatment
Planning
(Mairani et al 2013)
V
MCopt  VMCres 
Page 17
Pavia, Dec 16,
2014
VMCres
|D
100
 1.5%
Update on FLUKA use at CNAO
 The use of MC simulations to
verify and validate TPS results
proved to be useful for
clinical applications of
scanned proton therapy to eye
treatments
www.cnao.it
Eye-treatments with active scanning (VIII)
New DDDs now used
to characterize the first
CNAO “Eye-line”
configuration …
Page 18
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Eye-treatments with active scanning (X)
In the very next days, results
on lateral penumbra … 
Page 19
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Towards «new» ion species (I)
 CNAO phase I enlargment of the facility: experimental room
+ 3rd source for other particles
Already implemented and validated
CNAO beamline MC modelisation
to have a “premilinary look” to the
physical properties of new ion
species …
Page 20
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Towards «new» ion species (II)
 Beam size at the Isocenter
 MC simulation of the CNAO beamline
Page 21
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
www.cnao.it
Towards «new» ion species (III)
 Lateral spread in water of MC-calculated pencil beams with the similar
FWHM at the entrance (Bragg-Peaks around 14 cm in depth)
p - 142.7 MeV/u
12C
- 272.2 MeV/u (+ 2 RiFi)
4He
- 143.2 MeV/u (+ 2 RiFi)
16O
- 324.2 MeV/u (+ 2 RiFi)
… waiting for real experiments!
Page 22
Pavia, Dec 16,
2014
Update on FLUKA use at CNAO
Thank you
“Real progress happens only when advantages of a new technology become available to everybody”
H. Ford