ESTRO 36 Abstract Book

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S950 ESTRO 36 2017
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for cancer patients worldwide. This program is
administered through five RT and DI core support services:
site qualification, trial design support/assistance,
credentialing, pre- and post-case review data
management, and case review. IROC also provides
educational efforts to improve the understanding of the
protocols by participating institutions. IROC monitors over
2000 participating institutions that include nearly 100
participating institutions outside of North America.
Results
IROC currently provides core support for 172 NCTN trials
with RT, DI and RT/DI components. Many of these trials
were legacy trial from the previous cooperative group
program. IROC monitors nearly 1800 RT photon and 20
proton institutions. Over 28,000 beams outputs were
monitored with 8% of the sites requiring repeat audits due
to beam out of criteria. As part of credentialing, 950 QA
phantoms have been irradiated, 515 imaging modalities
evaluated and almost 4000 credentialing letters have been
issued. In just year 2, 5290 RT and 4934 DI patient datasets
were received (many using TRIAD) by IROC QA Centers to
be prepared for review. During the past 2 years, a total of
6300 RT cases and 19,000 DI image sets were reviewed by
IROC technical staff. To date, IROC has published 36
manuscripts.
Conclusion
The QA services provided by IROC are numerous and are
continually being evaluated for effectiveness, harmonized
across all NCTN Groups and administered in an efficient
and timely manner to enhance accurate and per protocol
trial data submission. These efforts increase each NCTN
Group’s ability to derive meaningful outcomes from their
clinical trials.
EP-1750 Enhanced radiotherapy by novel class of
radiosensitizers based Bismuth and Gadolinium
nanoparticles
S. Farahani1, N. Riyahi alam1, E. Gorji 2, R. Rahnamafar3,
S. Fazli4 , H. Khosravi5 , M. Pakravan1, V. Shahabian6, S.
Haghgoo2
1 Tehran University of Medical Sciences Radiation On,
Department of Medical Physics, Tehran, Iran Islamic
Republic of
2 Food & Drug Organization, Pharmaceutical Department-
Food & Drug Laboratory Research Center, Tehran, Iran
Islamic Republic of
3 Kashan University, Chemistry Department- Faculty of
Sciences, Kashan, Iran Islamic Republic of
4 Science and Research Branch- Islamic Azad University,
Nuclear Engineering Department, Tehran, Iran Islamic
Republic of
5 Tarbiat Modares University, Department of Medical
Physics, Tehran, Iran Islamic Republic of
6 Tehran University of Medical Sciences Radiation On,
Sina Specialized and subspecialty Hospital, Tehran, Iran
Islamic Republic of
Purpose or Objective
Recently, the use of nanoparticles with a high atomic
number as a new class of radiation sensitizers, to increase
the tumor dose and sparing normal tissues has become a
hot topic in radiotherapy treatments. Meanwhile, Bismuth
and Gadolinium based nanoparticles, can not only be used
in CT and MRI as contrast agents, but also can be feasible
radiosensitizers in radiotherapy. Hence they are attractive
candidates for multimodal dose enhancement studies. In
this study, the ability of dose enhancement of these
nanoparticles using MAGIC-f polymer gel under the
internal Iridium-192 and the external Cobalt-60
radiotherapy practices were investigated.
Material and Methods
The Bi2O3-NPs less than 40 nm in diameter and 0.1 mM
concentration were synthesized. To increase the precision
of the gel dosimetry a Plexiglas phantom was designed and
made, all of the gel filled vials (with and without the
nanoparticles) were irradiated to an Ir-192 radioactive
source simultaneously. Also, Irradiation was carried out
with a Co-60 teletherapy unit.
Results
The maximum dose enhancement factors under the
internal Iridium-192 radiotherapy were 31% and 22% in the
presence of Bi2O3-NPs and Gd2O3-NPs, respectively,
whereas these amounts were reduced to 1% in external
radiotherapy by Co-60 photons.
Conclusion
The results of our research approves the use of Bismuth
and Gadolinium based nanoparticles in brachytherapy.
Additionally, the polymer gel dosimetry can be a feasible
material for verification and estimation of dose
enhancements in the presence of nanoparticles.
EP-1751 A comparison of tools for Delivery Quality
Assurance in TomoTherapy
T. Santos1, T. Ventura2, J. Mateus2, M. Capela2, M.D.C.
Lopes2
1Faculty of Sciences and Technology, Physics
Department, Coimbra, Portugal
2IPOCFG- E.P.E., Medical Physics Department, Coimbra,
Portugal
Purpose or Objective
A TomoTherapy HD unit has recently been installed in our
hospital. The purpose of the present work is to establish
an accurate and efficient method of patient specific
delivery quality assurance (DQA). Four available tools
(EBT3 Grafchromic film, Dosimetry Check –DC –,
ArcCHECKTM and RadCalc®) have been tested and
compared.
Material and Methods
Standard patient plan verification in TomoTherapy is done
through film dosimetry in the Cheese Virtual WaterTM
phantom. Also point dose measurements can be performed
inserting ionization chambers in this phantom. A well-
established film absolute dosimetry methodology using
EBT3 Gafchromic film and applying a multichannel
correction method was developed in-house, adapting the
standard approach in the DQA Tomo station. The
treatment plans of the first 21 patients were
retrospectively verified using also Dosimetry Check
software (Math Resolutions, LLC) and ArcCHECKTM (Sun
Nuclear). A beta version of RadCalc®6.3 (LifeLine
Software Inc.) for TomoTherapy has been used for
independent treatment time calculation.
DC uses the MVCT detector sinogram to reconstruct the 3D
dose distribution. In this work it was used in pre-treatment
mode with the couch out of the bore. The transit dose
mode where the patient delivered dose reconstruction is
obtained was not assessed in this work. ArcCHECKTM
records the signal of 1386 diodes embedded as a helical
grid on a cylindrical phantom, enabling 4D volumetric
measurements.
The Gamma passing rate acceptance limit was 95% using a
3%/3 mm criterion in all cases.
Results
All the used QA tools showed a good agreement between
measured and planned doses. Film and DC achieved similar
results with mean Gamma passing rates of 98.8±1.6% (1SD)
for EBT3 film and 97.9±1.6% (1SD) for DC. Moreover, a
correlation was found between those results: when
passing rates using film were poorer (<97%), the same
happened with DC, while passing rates over 97% for DC
corresponded to the same range using film. This
correspondence was not verified with ArcCHECKTM where
Gamma passing rates were always close to 100%
(99.6±0.7% (1SD)).
Concerning the independent treatment time verification
with Radcalc®, the percentage difference to the Tomo
TPS calculation was 0.2±2.5% (1SD), on average.
Conclusion