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Intensity
modulated radio-surgery (IMRS) using the Peacock tomotherapy system
Bill J
Salter, Martin Fuss, Amir Sadeghi, Terence S Herman, Charles R Thomas, James M
Hevezi
UT Health
Science Center at San Antonio, San Antonio, TX; Cancer Therapy and Research
Center, San Antonio, TX
Purpose.
To implement key and necessary modifications to the Nomos Peacock IMRT system,
enabling the delivery of highly conformal and accurate radiosurgical treatments,
and to validate the viability of the system as a Radio-Surgical tool.
Materials
and Methods. The patient positioning device originally marketed by Nomos as the
CraneTM has been replaced by a new design for which a patent has been
obtained.
The new device enables the accurate delivery of obliquely oriented tomotherapy
arcs.
Additionally, a post collimation device, which reduces the physical size of
delivered pencil beams, has been designed and tested.
The Nomos Talon II invasive fixation system has been modified to provide the
accuracy necessary to Radio-Surgical applications.
A new class of inverse-planning objective-function Target and Tissue types
referred to by Nomos as RadioSurgery Target and RadioSurgery Tissue,
respectively, have been developed with the intent of improving the rate of dose
fall off for Radio-Surgical applications.
The viability of the modified system as a Radio-Surgical tool has been evaluated
with respect to: the smallest isodose volume treatable, the spatial accuracy of
delivery via TG54 hidden target test, the accuracy of planning system
"predicted" dosimetry, the whole body dose received by the patient,
and indices of conformality and homogeneity.
Results.
The previously mentioned modifications to the system have resulted in
significant improvements to both accuracy of delivery and conformality of
delivered dose, and the evaluation of the viability of the modified system for
Radio-Surgical applications has yielded promising results.
Numerous Radio-Surgical cases have been treated with the modified Peacock
system, each enjoying high degrees of conformality.
Representative dose distributions will be presented, along with follow-up
imaging sequences.
Conclusion.
The modified Nomos Peacock system implemented here represents a new and
promising method of treating Radio-Surgical lesions.
© Copyright 2002 American
Society of Clinical Oncology
Source:
http://www.asco.org/ac/1,1003,_12-002324-00_18-002002-00_19-002085-00_29-00A-00_42-00ONeill-00_43-00-00_44-00-00_45-00
Author-00_46-00Title-00_47-00Title-00_48-00and-00_49-00and,00.asp?cat=CNS+Tumors&parent=CENTRAL+NERVOUS+SYSTEM+TUMORS
&returnpid=2323 |
