IGRT; Implications for Quality Assurance - UTHSCSA ...radiology.uthscsa.edu/grad/Presentations/IGRT QA LFS.pdf · IGRT; Implications for Quality Assurance Luis Fong, ... • Define

SWSW--AAPMAAPM--FMOFM Joint Meeting FMOFM Joint Meeting QuerQueréétaro 2007 taro 2007

IGRT;IGRT;Implications for Implications for

Quality AssuranceQuality AssuranceLuis Fong, Ph.D.

SWSW--AAPMAAPM--FMOFM Meeting 2007FMOFM Meeting 2007IGRT; Implications for QAIGRT; Implications for QA

* Sandra Vieira, “Dosimetric Verification of Intensity Modulated Radiotherapy with an Electronic Portal Imaging Device”. Thesis, 2005. (drawn by Andy Bahnert)

Image-Guided Radiation Therapy (IGRT) concept


RT ProcessPrescription

Setup & Immobilization

Image Acquisition

Treatment Planning& Evaluation

Information Transfer& Management

Evaluation & Verification

TreatmentDelivery

PlanValidation

Corrective Intervention

MonitoringTreatment

IGRT FB loop

Target Localization

Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

+ IGRT

Advantages:


Target Localization Technologies (TLT)

Cyberknife

kV RadiographicUltrasound Portal Imaging

Varian OBI™Elekta Synergy™TomoTherapyHi-Art™

Siemens PRIMATOM™

kV and MV Cone-beam CTMV CTkV CT

Markers(Active & Passive)

Courtesy of Michael Sharpe, Ph.D. Princess Margaret Hospital, Toronto, CANADA


IGRT implementation process

• Decided that is time for IGRT

• Shop around• Purchase the

technology• Acceptance testing• Clinical

Commissioning

• Develop QA periodic tests:– Daily– Weekly– Monthly– Annual

• Provide proper training

• Ready to Go...


IGRT Feedback LoopPrescription

Setup & Immobilization

Imaging Acquisition

Treatment Planning& Evaluation

Information Transfer& Management


Evaluation & Verification

MonitoringTreatment

TreatmentDelivery

PlanValidation

IGRT FB loop


Clinical Implementation of ANYNew Technology

• Define clinical Questions BEFORE You Start!• Do your homework:

– Understand the IGRT solution: the clinical and technological limitations, the implementation process and the clinical advantages of the particular technology (papers, research, meetings, conferences, workshops, etc.)

• Understand how well the IGRT solution answers the clinical question you want to address.

• Understand how well the IGRT solution fits into the processes and infrastructure of your clinic.

• Get What you Need and also better fits your Processes!


Other Implications of new IGRT solutions

• Computing, networks, data storage

• Workload & workflow– Planning, Imaging, Treatment

time

• Risk/Benefit: – Imaging dose to untreated

anatomy– Geometric miss

• Backup system in case of IGRT solution failure

• Inter-discipline collaboration– shifting from traditional roles

• Decision making– Professional autonomy,

scope of practice

• Training & Education– Adoption– Practice guidelines,

communication and adaptation

– Organizational learning


IGRT implementation process

• Decided that is time for IGRT

• Shop around• Purchase the

technology• Acceptance testing• Clinical

Commissioning

• Develop QA periodic tests:– Daily– Weekly– Monthly– Annually

• Provide proper training

• Ready to Go...

There are no specific QA guidelines for

all the new technologies


Example of Clinical Implementation of IGRT Solutions


Definition of the Clinical Application

• The primary applications of EPID include:– Verification of patient setup– Assessment of target and organ motion. – Daily localization for prostate cancer patients

• Current research includes use of EPIDs:– for compensator design and verification, – treatment machine QA– patient dosimetry


Understanding the technology behind the solution

ConverterDetector

Data AcquisitionData ConversionImager Controller

Software Tools:• Image Acquisition Control• Image Enhancement • Image Analysis• Image Review• Matching

Beam

ImageStorage

Connectivity with other systems


Understand the Clinical Application of the IGRT solution

EPID for Treatment of Prostate Cancer

Bony Anatomy Vs. Fiducial Markers


0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15mm

Perc

ent

3DI VM 3DI B.A. 3DF VM 3DF B.A.

Effect of Correction: 3D - Target vs. Bones

Target p < 0.001Bones p = 0.46

Bones No change

Target Better


0%

20%

40%

60%

80%

100%

0 2 4 6 8 10 12 14

mm

Perc

ent

Pre VM C-C Pre B.A. C-C Thru VM C-C Thru B.A. C-C

Effect of Correction: Sup-Inf Component

Target better p<0.001

Fiducial MarkersVs.

Bony anatomy

Bones worse p<0.001


Using formulation proposed by Van Herk IJROBP 2002

Impact on Margins


Understanding and Testing the IGRT ToolDetected Field Edge Reference Field Edge

Anatomy MatchingDifference


Shift Calculation Spreadsheet


Shift Calculation and AssessmentPre-port Ant Field

Pre-port Right Lat Field


Patient data base


Implementation of IGRT solution in the Clinic Process Flow

Gold seeds implanted in the patient Simulation

R & V System(Multi-AccessTM)

Tx Planning:Localization fields are part of Tx

Contour seeds and bonny anatomy


Information transfer from TPS to:

Matching Software(Portal-VisionTM)

Images Acquired(Localization Fields)

Patient TxMonitoring Tx

Patient Setup

IGRT FB loop


IGRT Feedback Loop

Yes

Excel spreadsheetData entree and Calc

ANT & RT LATPre-Tx

Images during Tx(Two Fields)Patient Tx

Physician reviews &Approves

Matching(Portal-VisionTM)

Patient Setup


If SystematicShift

Physicist reviews shifts (After 5 Tx’s)

RecommendsSystematic shift

Apply shift

No

If 3D > 4mm

Yes


IGRT Feedback Loop

YesYes

Excel spreadsheetData entree and Calc

ANT & RT LATPre-Tx

Images during Tx(Two Fields)Patient Tx

Physician reviews &Approves


Patient Setup


If SystematicShift

Physicist reviews shifts (After 5 Tx’s)

RecommendsSystematic shift

Apply shift

NoNo

If 3D > 4mm

YesYes

Successful IGRT QA program

Gold seeds implanted in the patient Simulation

R & V System(Multi-AccessTM)

Tx Planning:Localization fields are part of Tx

Contour seeds and bonny anatomy


Information transfer from TPS to:

Matching Software(Portal-VisionTM)

Images Acquired(Localization Fields)

Patient TxMonitoring Tx

Patient Setup

IGRT FB loop


General QA points for EPID imager• Safety

– Arm and Imager collision interlock (Monthly)

• Mechanical Functionality– Arm and imager position

(Monthly)• Image quality

– Calibration (Monthly)– Noise (Daily & Monthly)– Contrast (Daily & Monthly)

• Data Transfer


New Technologiesor

Technology Upgrades


1.15 mm 0.75 mm 0.35 mm18S-3/218S-5/218S-4/235-5/3

0.46 mm0.89 mm

0.75 mm0.75 mm

MV

MV Image6 MV6 MU

400 MU/min

kV

kV Image75 kV80 mA40 ms

COOKTM Coils (Platinum) VisiCoilsTM (Gold)


New Hardware 4DITCTM

OBITM

Investigate how the new

technology fits into our processes and

infrastructure


Guideline for QA MV, kV & CB-CT


Preparing for 4D IGRT


0 %

4D CT & Phase Sorting

10 %

20 %

30 %

40 %

50 %

60 %

70 %80 %

90 %

• Use time-stamps to correlate:

Surrogate Phase

Image Phase

• GE LightspeedTM

scanner• Varian RPMTM

respiration management system

Courtesy of Yildirim Mutaf Ph.D.


Improving Temporal Accuracy • Quality of 4D imaging relies on accurate association of

the surrogate motion with the target– Accurate respiration determination / surrogate information– Temporal Accuracy → Spatial Accuracy

• In order to test the validity of the calculations performed by the commercial system, an in-house phase-calculation software was developed– Uses the raw data for the amplitude of the surrogate

displacement



PhaseCalc-ulation Software• User-friendly interface• Receives the raw data for the

displacement record of the surrogate marker

• Performs an independent calculation for the phase of the motion

• Compares the independent result to vendor calculation

• Lists the deviations as a list of slice locations for easier interpretation



Example Case• A valid respiration peak was missed with the commercial software

causing sub-optimal phase assignments to be used during image sorting…

• Deviations are observed for about 45 % of the clinical 4DCT cases– As large as 4-5 missing peaks are also observed…

• Similar observations are reported by other investigatorsE. R. Reitzel, G. T. Chen, Med. Phys. 33, 377 (2006)

A real patient study



Modified Phase Assignments

Pixel Difference Image=-Original Phase

Assignments

Cor

onal

Vie

w 1

Cor

onal

Vie

w 2



Comparing new IGRT solutions with what you already know

EPID+

Fiducial Markers

New Immobilization

Devices

2D kV Imaging

Gating

Ultrasound



The residual motion considered in the planning process was around 5 mm


Conclusion• Define the clinical application.• Create a team representing the different areas of the

department, that will use and manage the IGRT solution.• Take some time to understand the IGRT solution.• Look for the IGRT solution that addresses your clinical

need. • Understand how well the IGRT solution fits into the

processes and infrastructure of your clinic.• Get What you Need.• Test, Test, Test…• Develop a comprehensive QA program

that fits your processes.


Contributions• Michael Herman, Ph.D., Mayo Clinic, Rochester, MN• Jon Kruse, Ph.D. , Mayo Clinic, Rochester, MN• Yildirim Mutaf, Ph.D. , Mayo Clinic, Rochester, MN• Michael Sharpe, Ph.D. Princess Margaret Hospital, Toronto, CA


Some Useful References• Herman, M. G., J. M. Balter, et al. (2001). "Clinical use of electronic portal imaging: report of

AAPM Radiation Therapy Committee Task Group 58." Medical Physics 28(5): 712-37.• Yoo, S., G. Y. Kim, et al. (2006). "A quality assurance program for the on-board imagers." Medical

Physics 33(11): 4431-47.• Van den Heuvel, F., T. Powell, et al. (2003). "Independent verification of ultrasound based image-

guided radiation treatment, using electronic portal imaging and implanted gold markers." Medical Physics 30(11): 2878-87.

• Serago, C. F., S. J. Buskirk, et al. (2006). "Comparison of daily megavoltage electronic portal imaging or kilovoltage imaging with marker seeds to ultrasound imaging or skin marks for prostate localization and treatment positioning in patients with prostate cancer." International Journal of Radiation Oncology, Biology, Physics 65(5): 1585-92.

• Berbeco, R. I., T. Neicu, et al. (2005). "A technique for respiratory-gated radiotherapy treatment verification with an EPID in cine mode." Physics in Medicine & Biology 50(16): 3669-79.

• Schallenkamp, J. M., M. G. Herman, et al. (2005). "Prostate position relative to pelvic bony anatomy based on intraprostatic gold markers and electronic portal imaging." International Journal of Radiation Oncology, Biology, Physics 63(3): 800-11.

• Keall PJ, Mageras GS, Balter JM, et al., “The management of respiratory motion in radiation oncology; AAPM Report No. 91, Task Group 76”, Med Phys (2006);33: pp. 3874–3900.


Thanks!

Ready for some

questions

?


Documents

IGRT; Implications for Quality Assurance - UTHSCSA ...radiology.uthscsa.edu/grad/Presentations/IGRT QA LFS.pdf · IGRT; Implications for Quality Assurance Luis Fong, ... • Define