engelsman proton therapy workflow - aapm

[email protected] PSI Winterschool, January 2012

Proton Therapy Workflow Martijn Engelsman

HollandPTC and TU Delft

Disclaimer: I have no financial interest in any vendor of radiotherapy hardware,

software, or otherwise

[email protected] www.hollandptc.nl 2

Then •  Four field box •  Historical margins •  Lasers + X-ray •  Paperwork •  1 plan •  Long-term follow-up

Now •  IMRT, VMAT, RapidArc •  Error analysis -> margins •  CBCT •  Treatment chain

integration •  Adaptive therapy •  In-vivo dosimetry + long-

term follow-up

Closed loop

A brief history of photon therapy


Closed Loop: Check and Correct

Check Anatomy

Treatment plan

Check Delivery


300 2 4 6 8 10 12 14 16 18 20 22 24 26 28

160

0

20

40

60

80

100

120

140

Depth (cm)

Dos

e (%

)

Protons: Spread-out Bragg Peak

Protons: Pristine Bragg Peak

Beam Direction

Photons 10MV

Increaseddensity

The Promises and the Peril The Peril: Finite Range ! ! !

The Promises: Lower upstream dose No downstream dose


Dose degradation in proton therapy

Aafke Kraan et al. IJROBP 2013

Proton therapy needs to: -  Detect potential severe dose degradation -  Allow effective treatment plan adaptation


General patient complexity

(a.u

.)

Palliative Curative

Photons

Need for IGART

(a.u

.) Photons

Technology Status

(a.u

.)

Photons

The workflow challenge


(a.u

.)

Palliative Curative

Photons Protons

Need for IGART

(a.u

.) Photons Protons

Technology Status

(a.u

.)

PhotonsProtons


Patient intake


Patient referral

•  Standard indications –  Children –  Intra-ocular –  Base of skull

•  Other indications –  Head and neck –  Prostate –  Breast –  Lung –  Sarcoma –  Pancreas –  Liver –  Etc

We want to / will treat everything …using adaptive

(Intensity modulated) Proton Therapy !

Indication CMS Regence/group Premera/blue/cross Blue/Shield/California Aetna Anthem/blue/cr/blue/sh Humana UnitedHealthCare

Abdominal Investigational Investigational Investigational Investigational Investigational no

Acoustic/neuromas Investigational Investigational Investigational Investigational Investigational no

AVM Investigational Investigational Investigational Investigational Investigational yes yes

Bone/metastasis Investigational Investigational Investigational Investigational no

Breast Investigational Investigational Investigational Investigational Investigational Investigational no

Central/Nervous/System yes children children children yes yes yes yes

Cervix Investigational Investigational Investigational Investigational no

Chordoma///Chondrosarcoma yes yes yes yes yes yes yes yes

Head/and/Neck yes Investigational Investigational Investigational Investigational Investigational no

Hodgking Investigational Investigational Investigational Investigational no

Liver Investigational Investigational Investigational Investigational Investigational Investigational no

Lung Investigational Investigational Investigational Investigational no

Lymphoma Investigational Investigational Investigational Investigational no

Meningioma Investigational Investigational Investigational Investigational Investigational yes no

NonFHodgkin Investigational Investigational Investigational Investigational no

Ocular yes yes yes yes yes Investigational some yes

Paranasal/sinus yes Investigational Investigational Investigational Investigational no

Pediatric yes Investigational Investigational yes yes no

Pituitary yes Investigational Investigational yes yes yes no

Prostate very2few no no no no some some no

Rectum Investigational Investigational Investigational Investigational Investigational no

Retroperitoneal/sarcoma yes Investigational Investigational yes yes no

Sinus/tumors yes Investigational Investigational Investigational Investigational no

Skin/cancer Investigational Investigational Investigational Investigational Investigational no


Clinical reality Data part of a workflow survey of 12 US-based proton therapy

centers


Hospital-based or not?

Separate building

Stand-alone Embedded


Facility layout

1

8 9 13 1 4 5 7 10 12 2 3 11

Gantries 4 4 3 3 3 3 1 1 1 2 2 1

Fixed beam 1 1 2 1 1 1 3 3 3 1 0 0

Interplay? Some Some Some None Some Some Some Some Some Some None None

Only one center with more than two rooms claims no interplay effect.

Typically Pediatric patients, and sometimes SBRT patients, will get priority for beam usage as these are challenging cases.

Although some systems allow prioritization of beam requests, in other cases the rooms will coordinate by means of intercom.

Or one can simply wait, beam delivery time is typically acceptable, room switching is improving. (Only) large PBS fields in a slow scanning solution provide a real challenge.

No advanced scheduling system yet in clinical use, though (some) vendors are actively working on it and promising it to new customers.

Num

ber o

f tre

atm

ent

room

s

0

1

2

3

4

5

(a.u.)

Gantries Fixed beam


Treatment planning


Treatment planning workflow

1 2 3 4 5 6 7 8 9 10 11 12 Week:

Referral

CT/MRI Info

PTV1

PTV2

Plan 1

Plan 2

27th Tx 1st Tx

Info

1 2 3 4 5 6 7 8 9 10 11 12 Week:

Referral

PTV1 PTV2

CT/MRI

Plan 1 Plan 2 Plan 2‘

CT / Info

Info

Info 1st Tx 27th Tx

Plan 3

34th Tx

PTV3 Plan 1 ‘


0

2

4

6

8

10

12

14

16

cranial

#"Fields"

2"

4"

6"

8"

10"

12"

14"

16"

0"

Fields per treatment course


Treatment planning effort

Photons 200 – 300 Protons 60 – 110

Patients planned per FTE dosimetrist

Do I need photon back up planning?


Treatment Planning

•  Commercially available TPS –  CMS XiO –  Varian Eclipse –  Raysearch Raystation –  Philips Pinnacle –  ( Astroid )

Model your specific

machine?

•  Auto-patching and auto-matching •  Dose accumulation and deformation •  Scripting / auto-planning •  Multi-criteria optimization (MCO) •  Re-painting strategies

Tools to look for to make life easier


Signatures

1

Treatment(plan Calibra.on Setup(image FieldPhysician 100 83 75 25Physicist 92 100 25 17

Dosimetrist 67 25 25 0

Therapist 17 0 67 92

Perc

ent

0

25

50

75

100

Physician Physicist Dosimetrist Therapist

Treatment plan Calibration Setup image Field


Integration / connectivity

Very few users for each package / combination

TPS OIS TDS Patient

In-House (3)

Hitachi (1)

IBA (7)

Mevion (1)

Varian (1)

In-House (2)

Elekta XiO (4)

Raystation (2)

Varian Eclipse (7) Aria (4)

Mosaiq (8)

Velocity (3)

Mimvista (4)

In-House (1)

Next to using the TPS itself

DIPS (3)

Medcom Verisuite (5)

By proton vendor

In-House (1)

Delineation Treatment planning Record and Verify Proton therapy equipment

Setup verification

Delineation Treatment Planning OIS TDS

Setup verification


OIS and connectivity


Integration status

For a not yet too difficult treatment / workflow:

•  “The integration between TPS and OIS is acceptable. The challenge is mainly in the communication between OIS and TDS.”

•  “We do a lot of in-house manipulations to make our OIS work with protons.”

•  “There is no integration whatsoever.”

•  “No way this system can be integrated.”

“Are you happy about the electronic integration between TPS, OIS and TDS?”


Image-guidance


IGRT and ART, until now

•  State of the art –  Daily Orthogonal X-rays (plus some off-line imaging)

•  Auxiliary positioning systems –  Ultrasound –  VisionRT –  Fiducial markers –  Electromagnetic Transponder Tracking

•  Treatment adaptation –  Off-line CT –  Slow adaptation -> TPS vendors picking up the pace

•  Remote positioning •  E.g. Fava et al. Radiother Oncol.103, p.18, “In-gantry or remote patient

positioning? Monte Carlo simulations for proton therapy centers of different sizes.”


Orthogonal X-ray alignment

Pro •  On-line setup protocol •  6-DOF setup correction

Con •  Time-consuming •  Intra-operator variability •  Rotations are difficult •  No treatment adaptation

•  Dose degradation remains unknown !

Aligning the tumor is not even half the solution !


Cone-beam CT at isocenter (photons, 2009)

Slide courtesy of J-J. Sonke, NKI

Room entrance to first

“beam-on”: 6 minutes

+

VMAT / RapidArc 4 minutes

=

10 minute fraction

[email protected] www.hollandptc.nl 25 1

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Setup times 0 10 35 16 10 2 3 3 0 4 1 0 2 0 0 1 0

Cou

nt (#

)

0

10

20

30

40

Patient setup time (minutes)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Fraction times in proton therapy (2014)

1

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Setup times 0 10 35 16 10 2 3 3 0 4 1 0 2 0 0 1 0

Cou

nt (#

)

0

10

20

30

40

Patient setup time (minutes)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

1

0 10 20 30 40 50 60 70 80 90 100 110 120

Fraction times 0 6 24 34 12 2 6 0 0 2 0 0 1

Cou

nt (#

)

0

10

20

30

40

Total in-room time (minutes)

0 10 20 30 40 50 60 70 80 90 100 110 120

Setup time (minutes) Fraction time (minutes)

Anesthesia or SBRT Anesthesia or SBRT


Frequency of setup verification

1

Peadiatric Intra+cranial Gastro Prostate H&N Thoracic SBRT

Every field 67% 58% 58% 67% 58% 58% 88%

Every fraction 33% 42% 42% 33% 42% 42% 13%

Perc

ent

0%

20%

40%

60%

80%

100%

Peadiat

ric

Intra-

crania

l

Gastro

Prostat

eH&N

Thorac

icSBRT

Every field Every fraction


3D in-room imaging

CBCT

•  Volumetric matching •  Visualize anatomy changes

•  Dose recalculation

In-room CT

Having on-line 3D imaging is not even half the solution !

Need for decision protocols and software to (semi-)automate these


Treatment adaptation


Repeat CT: Examples of clinical application

Chang et al. IJROBP2014, p.809

- Adaptive IMPT at MD Anderson - Weekly repeat CT and recalculation - 9/34 patients had to be replanned - In two cases to ensure OAR sparing - 3 days to start of new plan

most of these patients, IMPT was the only option fortreatment because of the need for normal tissue sparing.Typically, IMPT was chosen because of a significant dosi-metric advantage over other modalities (Fig. 2B) or becauseit was the only option for definitive treatment to sparespinal cord, esophagus, and lung (Fig. 2C), or because ofrecurrent disease that had been treated previously with ra-diation therapy (Fig. 2D).

Analyses of tumor motion, WET, beam angleselection, and plan robustness

Beam angle‒specific tumor motion and WET analyseswere performed for each patient as described in Methods.The absolute WETs of the pixels within the ITV forevery tested beam angle were calculated on T0 and T50phases. The WETs of the pixels on the distal surface of

the ITV orthogonal to the beam (beam angle Z 0) wereprojected to a plane and shown as a 2D map (Fig. 3).Figure 3A shows the WET change between T0 and T50as a function of incident proton beam angle, andFigure 3B shows an example of the same patient at abeam angle of 160!. The S5mm for this beam angle was95.1%. Optimal beam angles that minimized the effect ofrespiratory motion were then selected based on theseanalyses. Findings from patient-specific tumor motionand WET analyses are summarized in Table 2. The datashowed a median 86.2% of the voxels in the IGTV thattraveled in perpendicular to the beam axis by "5 mm.The data also met our acceptability limit of #80% of thevoxels in the ITV in which the WET differences are notmore than 5 mm (S5mm).

The results of a robustness analysis of an MFO IMPTplan for a representative patient are shown in Figure 4.The maximum deviation from the nominal dose-volume

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Lung V5 (%)

Lung V20 (%)

MLD (Gy)

Heart V40 (%)

Esophagus V60 (%)

CTV D5 (Gy)

CTV D95 (Gy)

GTV D5 (Gy)

GTV D95 (Gy)

IMRT

PSPT

IMPT

Esoph 60Gy

PSPT IMPT

IMRT IMPT

IMPT:solid PSPT:dotted IMRT:dashed

CTV

A

B CTV

Esophagus

Lung

IMPT vs IMRTMLD reduction: 4.4 Gy

IMPT vs PSPTMLD reduction: 4.3 GyEsophagus V65: 3% vs 10%

10020.0

Mean Lung Dose

PSPT IMRT IMPT IMPT IMPT SFO MFO Robust

15.0

10.0

Dose (cGy)

Norm

aliz

ed V

olum

e (%

)

Norm

aliz

ed V

olum

e (%

)

Dose (cGy)

80

60

40

20

0

0

2000 4000 6000 8000 10000 0 2000 4000 6000 8000 10000

100

80

60

40

20

0

Fig. 2. (A) Comparison of dosimetric variables for intensity modulated proton therapy (IMPT), passive scattering protontherapy (PSPT), and intensity modulated radiation therapy (IMRT). Values shown are means of all patients. (B) Comparisonsof dose-volume histogram (DVH), isodose distributions, and total mean lung dose for a representative patient who receivedchemotherapy with IMPT to 74 Gy(relative biological equivalence [RBE]) for stage III NSCLC.

Volume 90 $ Number 4 $ 2014 IMPT in thoracic malignancies 813


Clinical reality: Adaptive proton therapy

1

Peadiatric Intra-cranial Gastro Prostate H&N Thoracic SBRT

never 33.3% 66.7% 50.0% 75.0% 25.0% 33.3% 62.5%

1x 50.0% 33.3% 25.0% 25.0% 41.7% 16.7% 0.0%

2x 8.3% 0.0% 8.3% 0.0% 16.7% 16.7% 0.0%

3x 0.0% 0.0% 0.0% 0.0% 8.3% 8.3% 25.0%

4x 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 12.5%

5x 8.3% 0.0% 16.7% 0.0% 8.3% 16.7% 0.0%

6x 0.0% 0.0% 0.0% 0.0% 0.0% 8.3% 0.0%

0%

25%

50%

75%

100%

Peadiatric

Intra-cranial

Gastro

Prostate

H&N

Thoracic

SBRT

never 1x 2x 3x 4x 5x 6x

a) # of re-calculations per patient

0.0%

25.0%

50.0%

75.0%

100.0%

Peadiatric

Intra-cranial

Gastro

Prostate

H&N

Thoracic

SBRT

never 1x 2x 3x 4x 5x 6x

b) # of re-plannings per patient

On average: 75% never or once On average: 85% never or once


Adaptive Therapy Vision (2013 PTCOG)

•  0 years –  Off-line, next 2-3 days

•  5 years – On-line evaluation of plan adequacy and choice of plan

of the day

•  10 years –  10 second automated on-line plan re-optimization


Example: online adaptive PT

2. Daily plan selection on the basis of in-room CT scanning plus dose-recalculation

1.  Create treatment plan library using individualized motion model and/or variable plan robustness

Fast on-line dose recalculation is at the moment proton therapy’s best bet for validating continued plan adequacy!


Clinical reality: Moving tumors

1

Margins Breath-hold Gating Repainting

100% 50% 8.3% 8.3%

Perc

enta

ge o

f ins

titut

es

0%

25%

50%

75%

100%

Margins Breath-hold Gating Repainting


The other workflow

Not patient-specific but

indication specific


Margins

IGART


Margins •  Range error •  Setup error •  Number and direction of

beams •  Use of ITV •  Dual-Energy CT •  …

IGART •  Frequency of imaging •  Kind of imaging (X-ray,

CBCT, in-room CT •  Plan of the day •  Prompt-gamma imaging •  …

4D error simulation platform for do-it-yourself analysis.

What we need

The balance in proton therapy


Rescanning variables

•  Spot size •  Lateral spot overlap •  Distal spot overlap •  Volumetric or layer repainting •  Number of rescans •  Number of treatment fractions •  Number of beams in the plan •  Simultaneous gating or breath-hold •  Iso-layer or scaled-rescanning •  Spot-, line- or contour-scanning •  Uniform, phase-controlled, random, time-delay, … •  Layer changing time (vendor dependent) •  Re-image and re-plan approach •  …

Different answer for: -  Each indication? -  Each patient?


Quality Assurance


Dosimetric quality assurance

•  Extent depends on: –  Facility layout (e.g. # rooms) –  Your beamline(s) (e.g. PSPT, universal nozzle, PBS) –  Patient mix (gating, tracking, …) –  Experience –  Patient specific?

•  No standard approaches (yet) –  QA tools and QA program –  Technically demanding (who can do it)

•  Night-time and morning work

Imaging QA to 1st order similar to photon therapy


QA time needed:

QA Time Daily 10 – 30 minutes per room Weekly 5 hours per week Monthly 5 – 25 hours per month Modality switch Followed by daily QA Fields: Hardware (PSPT) 0.5 – 1.0 FTE Fields: Dosimetric 5 – 15 hours per week

Overall QA time in % of yearly clinical operational hours:

Photons: Protons:

10% 20%

60% of PSPT 100% of PBS


Facility start-up


Indications treated

Pedia

tric

Sarco

mas

Gastro

-intes

tinal

Pros

tate

Head a

nd ne

ck

Lung

Pe

lvis

Breast

1

Prostate Pediatric H&N Sarcoma's Gastro-intestinal Lung Pelvis Breast

1st year 100 100 50 50 40 50 50

2nd year 50 25 40 50 50

3rd year 25 50

4th year 20 50

Perc

ent

0

25

50

75

100

Prostat

e

Pediat

ricH&N

Sarcom

a's

Gastro-

intest

inalLun

gPelv

isBrea

st

1st year 2nd year 3rd year 4th year


Staffing (for 500 patients per year)

Phys

ician

s

Phys

icists

Ther

apist

s

Dosim

etrist

s

Full-

time

Empl

oym

ent (

FTE)

5

10

15

20


Closed Loop: Check and Correct

Check Anatomy

Treatment plan Check Dose

Check Delivery

Improved treatment plan design

Best possible imaging

Dose recalculation

In-vivo dosimetry


The workflow challenge


(a.u

.)

Palliative Curative

Photons Protons

Need for IGART

(a.u

.) Photons Protons

Technology Status

(a.u

.)

PhotonsProtons

Technology Status

(a.u

.)

PhotonsProtons


Conclusions

We are here

Quality, integration and efficiency of proton therapy

•  More and better tools •  More and better use •  More patient benefit


Thank you

M. Engelsman www.hollandptc.nl

[email protected]

engelsman proton therapy workflow - aapm

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