Robert S' Kwon, M'D', Muthana S' A' L' AlGhazi, Ph'D', Jeffrey V' Kuo, M'D', Nilam S' Ramsinghani, M

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DYNAMIC IMRT WITH PEACOCK
THE UNIVERSITY OF CALIFORNIA, IRVINE EXPERIENCE
Robert S. Kwon, M.D., Muthana S. A. L. Al-Ghazi,
Ph.D., Jeffrey V. Kuo, M.D., Nilam S.
Ramsinghani, M.D., Richard H. Yakoob, M.S.
Department of Radiation Oncology
University of California, Irvine
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Multileaf Intensity Modulating Collimator (MIMiC)
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CraneTM attachment for precision treatment table
indexing
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Treatment Planning Computer
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CT Imaging
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Dosimetric Measurements Required Prior to
Clinical Use

• 1. Two-dimensional scans of the beam profile for
  the beam produced by opening a single central
  leaf at 10cm depth in water and 100cm SSD
  (OARi(r) for leaf i)
• 2. Beam profiles at a number of depths for a
  field produced by fully opening the MIMiC ( 2x20
  cm2 ) Enable PDD and TMR determination.
• 3. ROFs at central axis for different field
  sizes.
• (1x1 - 2x20 cm2 )
• 4. Dose / MU to determine a calibration factor.

Instruments used Diode (p type Si 0.09mm3),
Markus Chamber (0.045cm3), Film
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Dose Calculation Algorithm
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Patient Characteristics
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INDICATIONS FOR PEACOCK
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Site Distribution
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CNS Histology
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Head and Neck Treatment Sites
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Patient Immobilization
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Immobilization Devises Cranial and HeadNeck
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Immobilization Devices Body Mask
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TREATMENT PLANNING PARAMETERS
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Craniopharyngioma 15 Gy/1f post 32P treatment, 2
targets.
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Recurrent Glioma 60Gy/30f Post 55.8Gy/31f
EBRTResection
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Lung tumor 2 targets, 1 abutting the heart, 20
Gy/10 f boost after 40 Gy EBRT.
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Chordoma of the Buttock 30Gy/15f (Post-op.
50.4Gy EBRT 62Gy Ir-192)
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Ca. Prostate 32Gy/16f Boost (Post 40Gy/20f EBRT)
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Field Placement Verification Cranial Case
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Field Placement Verification Cranial Case
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Dosimetric Verification in Phantom Prostate
(a) Calculated
(b) Film
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Dose Distribution Verification Prostate
(a) Calculated
(b) Measured (Film)

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CONCLUSIONS

• 1. Relevant dosimetric data were acquired to
  enable clinical use of the system.
• 2. Patient immobilization is achieved using the
  Talon system for selected cranial cases or an
  acquaplast mask for the remainder of sites
  treated.
• 3. Accuracy of positioning and delivery is
  within 1mm for Talon cases and 2mm for mask
  cases. This is verified by weekly port films.
• 4. The dose/fractionation schemes employed are in
  the range 15Gy/1f - 80Gy/40f.
• 5. Multiple target (up to 3) can be treated in
  one set-up.

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CONCLUSIONS (contd.)

• 6. The range of target volumes treated is 2-500
  cm3
• 7. To date 100 patients have been treated.
• 8. Dosimetric accuracy of treatment delivery was
  verified by film, TLD and ion chamber
  measurements in phantom to be within /- 5.
• 9. This approach provides an opportunity for dose
  escalation studies.
• 10.The system is fitted to a standard linac
  without major modifications

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Acknowledgements

• Robert Sanford, PhD, Heeteak Chung and Rina Lim
  B.S. for assistance with dosimetric verification
  and preparation of the manuscript.