palliative radiotherapy using cone beam ct
TRANSCRIPT
A One Step Model for Online A One Step Model for Online Planning and Treatment for Planning and Treatment for
Palliative Radiotherapy using Palliative Radiotherapy using Cone Beam CTCone Beam CT
David Fitzpatrick, Anita David Fitzpatrick, Anita VloetVloet, Daniel Letourneau, , Daniel Letourneau, Rebecca Wong, Mary Rebecca Wong, Mary GospodarowiczGospodarowicz, David A , David A JaffrayJaffray
5th Annual Toronto Radiation Medicine Conference
Kingbridge Sunday 27 April 2008
BackgroundBackground
• Palliative radiation should be effective yet fast • Uses simple Techniques
– Ant/Post opposed fields – A Direct field
• Conventional CT planning – a multistep process– can take a few hours to 1-2 days
• 2D planning – Quicker than CT planning– But lacks dosimetric information
Cone Beam CT (CBCT)Cone Beam CT (CBCT)
• CBCT scan images can be rapidly acquired on an RT treatment unit
• CBCT established for Image Guided RT Jaffray, Kupelian at al Expert Rev Anticancer Therapy 2007
• CBCT recently developed to permit image quality sufficient for treatment planning Letourneau, Wong et al IJROBP 2007. Sharpe, Moseley et al Med Physics 2006.
33
Conventional CT Simulation (PCT) Conventional CT Simulation (PCT) Planning and RT Planning and RT
Volumetric Imaging
Planning
QAand
IGRT
Time: Many Hours to 1-2 Days
Conventional Planning ProcessPLANNING CT
EXPORT IMAGES TO TPS
PHYSICS QA
QA ROOM
TREATMENT UNITPT SET UP + IGRT
TREATMENT DELIVERY
PLANNING +DR APPROVAL
PT WAITS FOR RT
CONTOURING
WEB PUBLISHINGEXPORT PLAN TO RT UNIT
PT HAS RT
33
A CBCT enabled Online Treatment StrategyA CBCT enabled Online Treatment Strategy
Volumetric ImagingOnline
Planning
DeliveryQAand
IGRT
Study ObjectiveTo Replace a multistep PCT process by a
1 step 30 min appointment at the treatment unit.
MethodsMethods• Phase A
– Is the image quality adequate for planning? • Spine, Mediastinum, Abdomen/Pelvis• Suitable for CT planning• n = 3x3
• Phase B– Trial on-line planning within the clinical environment – n = 45 (15 spine, 15 thoracic, 15 abdomen/pelvis)
• Phase C– Testing the efficacy of the established on-line planning
system to treat patients. – n = 60 (15 spine + 15 bone, 15 thoracic, 15 abdomen/pelvis)
MethodsMethods• Outcomes
– Agreement between CBCT and PCT defined GTV– Adequacy of coverage of PCT generated PTV by
CBCT plan 90% isodose– Time– Patient satisfaction rates
Phase APhase A
Spine or mediastinum or abdominal disease
For palliative RT
Conventional Conventional Planning CT Planning CT
(PCT)(PCT)
Cone beam capable treatment unit PCTPCT
CBCTCBCT
DRRDRR
UNDERCOVERAGE by CBCT v PCT
OVERCOVERAGE by CBCT v PCT
Overlap
Phase A GEOGRAPHIC AREA COMPARISON
CBCT/DRR PCT/DRR CBCT/PCT
Mean ±SD% Mean ±SD% Mean ±SD%
% UC 46 ±
61 42 ±
47 11
% OC 31 ±
34 29 ±
34 11
% Overlap 57 ±17 57 ±16 80
Phase BPhase BSpine
Mediastinum For Pall RT
Abdomen/Pelvis
PCT plan used to treat patient
During 1 fraction of treatment a CBCTscan acquired images and
CBCT study plan generated
CBCT Plan CBCT Plan vsvs PCT Plan PCT Plan
Spine Mediastinum/lung
Abdomen pelvis
Field Areamean (SD)
n = 16
Field Areamean (SD)
n = 15
Field Areamean (SD)
n = 13*% UC 12 (13) 18 (16) 20 (15)
% OC 15 (21) 21 (24) 10 (13)
% OL 89 (13) 82 (15) 80 (15)
Phase BPhase B
• Adequacy of CBCT plan 90% isodose coverage of PCT generated PTV- Spine - 93 + 11 %- Mediast – 89 + 15%- Abd/Pelvis – 92 + 5%
PTVPCTPCT
CBCT plan 90% isodose line
Phase B Phase B -- Timing resultsTiming results
CBCTPatient or
Institution's perspective
Planning CTPatient's Perspective
Planning CTInstitution's Perspective
Total Time 28+/- 8 min 30 +/- 12 min 149 +/- 78 min
Phase BPhase B
PCT PCT Process:Process:
GTV GTV PCTPCTFields Fields PCTPCTTime Time PCTPCT
Pt satisfaction Pt satisfaction PCTPCT
Phase CPhase C
Bone only to dateBone only to dateMediastinum
Abdomen/Pelvis
Cone beam scan acquired on treatment
unit and CBCT generated plan used to
treat patient
Conventional Planning CT
for Retrospective validation
1 Step ProcessPatient Set Up
CBCT Image Acquisition Images Exported to TPS
Define PTVPlanning
Plan PublishedExport Plan to RT unit
Dr. Approval + QA IGRT CBCT
Treatment Delivery
Task Professional Time (min)
Patient Walk in and Setup MRT(T) 8.3 ± 2.2
CBCT Acquisition and Export MRT(T) and Planner 6.3 ± 2.1
Dr Contouring RO 3.4 ± 1.3Planning / Export / WebPub Planner 9.9 ± 3.0
QA, Approval and CBCT #2 QA_Phys, RO and MRT(T) 8.7 ± 2.6
Treatment Delivery MRT(T) 2.5 ± 0.5
Patient Walk out MRT(T) 2.3 ± 1.0
Total ------ 39.3 ± 6.8
Phase C Elapsed TimePhase C Elapsed Time (10 spine patients)
MRT(T): Therapist, RO: Radiation oncologist and QA_Phys: QA physicist
Phase C Total Elapsed TimePhase C Total Elapsed Time (10 patients)
Satisfaction dataSatisfaction data 1= strongly agree, 2 = agree, 3 neither agree/disagree, 4 disagr1= strongly agree, 2 = agree, 3 neither agree/disagree, 4 disagree, 5 strongly disagreeee, 5 strongly disagree
Median (Range)
Previous XRT 4 Yes 3 no (3 NA)
Planning and treatment process uncomfortable 4 (3-5)
Inconvenient 4 (2-5)Process difficult 4 (4-5)
Difficulty lying in position 3.5 (1-5)Took a long time 3.5 (2-5)
Efficient 2 (1-5)Satisfied with care 1 (1-2)
Clinical Advantages of 1 Step Online Clinical Advantages of 1 Step Online Planning and TreatmentPlanning and Treatment
• 1 step (less handoffs)• Time efficiency from Institutional perspective• Weekend on call
– Minimize pt transfer between units when staff minimal– Do not require staff trained to operate both CT Simulator
and RT treatment unit• Same day Sim + Treatment start• Minimize delays due to sequencing between systems• Could potentially be used in developing countries
for 3D simulation and Planning
Thank You forThank You for Your AttentionYour Attention