This document describes a one-step model for online planning and treatment of palliative radiotherapy using cone beam CT (CBCT). In phase A, CBCT image quality was found to be adequate for treatment planning. Phase B involved online planning with CBCT for 45 patients, showing good agreement with conventional planning CT. Treatment plans were delivered in an average of 28 minutes from patient arrival. Phase C is ongoing to further test the efficacy of this one-step CBCT planning approach in reducing planning time and improving patient satisfaction compared to conventional multi-step planning CT.

1. A One Step Model for Online
Planning and Treatment for
Palliative Radiotherapy using
Cone Beam CT
David Fitzpatrick, Anita Vloet, Daniel Letourneau,
Rebecca Wong, Mary Gospodarowicz, David A Jaffray
5th Annual Toronto
Radiation Medicine Conference
Kingbridge
Sunday 27 April 2008

2. Background
• 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

3. 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.

4. Conventional CT Simulation (PCT)
Planning and RT
Time: Many Hours to 1-2 Days
Volumetric Imaging
Planning
QA
and
IGRT
3

5. Conventional Planning Process
PLANNING CT PT WAITS FOR RT
EXPORT IMAGES TO TPS
CONTOURING
PLANNING +
DR APPROVAL
PHYSICS QA
QA ROOM
WEB PUBLISHING
EXPORT PLAN TO RT UNIT
TREATMENT UNIT
PT SET UP + IGRT
PT HAS RT
TREATMENT DELIVERY

6. Study Objective
To Replace a multistep PCT process by a
1 step 30 min appointment at the treatment unit.
A CBCT enabled Online Treatment Strategy
Volumetric Imaging
Online
Planning
QA
Delivery and
IGRT
3

7. Methods
• 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)

8. Methods
• Outcomes
– Agreement between CBCT and PCT defined GTV
– Adequacy of coverage of PCT generated PTV by
CBCT plan 90% isodose
– Time
– Patient satisfaction rates

9. Phase A
OVERCOVERAGE by CBCT v PCT
Spine or mediastinum or
abdominal disease CBCT
For palliative RT
Overlap
Conventional
Planning CT
(PCT)
Cone beam capable
treatment unit PCT DRR
UNDERCOVERAGE by CBCT v PCT

10. Phase A GEOGRAPHIC AREA COMPARISON
CBCT/PCT
CBCT/DRR PCT/DRR
Mean ±SD% Mean ±SD% Mean ±SD%
46 ± 61 42 ± 47 11
% UC
31 ± 34 29 ± 34 11
% OC
57 ±17 57 ±16 80
% Overlap

11. Phase B
Spine
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

12. CBCT Plan vs PCT Plan
Spine Mediastinum/ Abdomen pelvis
lung
Field Area
Field Area
Field Area
mean (SD)
mean (SD)
mean (SD)
n = 13*
n = 15
n = 16
% UC 12 (13) 18 (16) 20 (15)
% OC 15 (21) 21 (24) 10 (13)
% OL 89 (13) 82 (15) 80 (15)

13. Phase B
• Adequacy of CBCT plan CBCT plan 90% isodose line
90% isodose coverage of
PCT generated PTV
- Spine - 93 + 11 % PTVPCT
- Mediast – 89 + 15%
- Abd/Pelvis – 92 + 5%

14. Phase B - Timing results
CBCT
Planning CT
Patient or
Planning CT
Institution's Institution's
perspective Patient's Perspective Perspective
Total Time 28+/- 8 min 30 +/- 12 min 149 +/- 78 min

15. Phase B C
Phase
Bone only to date
1 Step Process
Mediastinum
Patient Set Up
Abdomen/Pelvis
PCT
CBCT Image Acquisition
Process: Exported to TPS
Images
Define PTV
Cone beam scan GTV PCT
Fields PCT Planning
acquired on treatment
unit and CBCT Time PCT Plan Published
generated plan used to Pt satisfaction PCTPlan to RT unit
Export
treat patient
Dr. Approval + QA
IGRT CBCT
Conventional Planning CT
Treatment Delivery
for Retrospective validation

16. Phase C Elapsed Time (10 spine patients)
Task Time (min)
Professional
Patient Walk in and Setup 8.3 ± 2.2
MRT(T)
CBCT Acquisition and Export 6.3 ± 2.1
MRT(T) and Planner
Dr Contouring 3.4 ± 1.3
RO
Planning / Export / WebPub 9.9 ± 3.0
Planner
QA_Phys, RO and
QA, Approval and CBCT #2 8.7 ± 2.6
MRT(T)
Treatment Delivery 2.5 ± 0.5
MRT(T)
Patient Walk out 2.3 ± 1.0
MRT(T)
Total ------ 39.3 ± 6.8
MRT(T): Therapist, RO: Radiation oncologist and QA_Phys: QA physicist

17. Phase C Total Elapsed Time (10 patients)

18. Satisfaction data
1= strongly agree, 2 = agree, 3 neither agree/disagree, 4 disagree, 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)

19. Clinical Advantages of 1 Step Online
Planning 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

20. Thank You for
Your Attention