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a defined volume at a sequence of time points using QI, (III) integration
of the time sequence of measured activity values, (IV) calculation of the
absorbed dose from the activity–time integral. Each link in this chain may
involve methods and procedures for which there is as yet no harmonized
approach.
Conclusions:
An agreed dosimetry protocol is needed to raise MRT treat-
ments to an acceptable level. Standardization and harmonization of nuclear
imaging procedures for QI is the first step toward the development of a
dosimetry protocol for MRT. The aim of the MetroMRT project was to provide
a standardized methodology for calculating of internal dose quantities and
associated uncertainties. In the present paper the steps taken toward the
development of an international protocol are presented, along with the major
results achieved.
http://dx.doi.org/10.1016/j.ejmp.2016.01.358C.353
DOSIMETRIC VALIDATION AND COMPARISON OF A NOVEL ELECTRONIC
DOSIMETRIC SYSTEM FOR NUCLEAR MEDICINE RADIATION PROTECTION
A. Daniele
* , a ,E. Nicolai
a ,N. Franza
b ,A. Tonnett
i b .a
IRCCS SDN, Napoli, Italy;
b
DOSIMETRICA, Nocera Inferiore (NA), Italy
Purpose:
A growing use of diagnostic medical examination using ioniz-
ing radiation is observed but the risk associated for the operators who attend
them in this procedures is not always clear and is necessary a dosimetric
instrumentation for operators who really are subject to continuous expo-
sure of nuclear medicine radiations. The purpose of this work is to evaluate
the dosimetric property of a novel electronic pocket dosimeter by com-
parison with commercial dosimetric devices and to compare it with the
TLD dosimeter in the clinical routine.
Methods and Materials:
The dosimetric device is an electronic semicon-
ductor pocket dosimeter (Aloka, Hitachi) that allows to check at any time
the accumulated amount of radiation exposure. The Energy threshold of
the device is of 40 keV with a measurement dose ranging from 1 μSv to
10 Sv. The measurement has been performed in the NM department of the
Diagnostics and Nuclear Research Institute SDN in Naples. The dosimetric
validation of the dosimeter is assessed by an intercomparison with a camera
and a spectroscope in terms of dose and dose rate and 2 months study for
the comparison of the pocket dosimeter and a commercial TLD.
Results:
A very good agreement between the electronic dosimeter, the
camera and the spectroscope was found. A linear fit for different activity
dose and the measured dose has been reported. The same linear fit with
an R2 equal to 1 is found in the comparison between the pocket dosim-
eter and the TLD dosimeter.
Discussion:
The accuracy of the electronic dosimeter has been found com-
parable with that of calibrated reference instruments, with a negligible
difference within 5%. Different measures of absorbed dose and dose rate
for different activity source have shown a good linear fit. The comparison
with the TLD dosimeter has established that the electronic pocket dosim-
eter is a good candidate to be used in the clinical routine in the Nuclear
Medicine department for the operative radiation protection.
http://dx.doi.org/10.1016/j.ejmp.2016.01.359C.354
PERFORMANCE OF MEDIPROBE COMPACT GAMMA CAMERA
F. Di Lillo
* , a , b ,V. Corvino
a ,A. Sarno
a , b ,G. Mettivier
a , b ,P. Russo
a , b .a
Dipartimento di Fisica, Università di Napoli Federico II, Napoli, Italy;
b
INFN
Sezione di Napoli, Napoli, Italy
Introduction:
The aim of this work is to assess the performance of a pro-
totype compact gamma camera (MediPROBE) based on a semiconductor
hybrid pixel detector. This probe could be adopted for various tasks as pre-
operative sentinel lymph node localization, breast imaging with 99Tc-
sestamibi and thyroid imaging with iodine radioisotopes.
Material and Methods:
The hybrid detector is an assembly of a 1-mm thick
CdTe detector (sensitive area 14.08
×
14.08mm
2
) electrically connected pixel-
by-pixel to a photon-counting CMOS ASIC of the Medipix2 series (256
×
256
square pixels, 55-μm pitch). MediPROBE is equipped with a set of three
interchangeable knife-edge pinhole collimators (hole aperture of 0.78 mm,
1 mm, and 1.9 mm) and with a coded aperture mask. Measurement of field
of view (FOV), system spatial resolution and system sensitivity were per-
formed by using a capillary (0.85 mm inner diameter) filled with 7400 kBq
99mTcO4- (140 keV) and a sealed gamma-emitting 241Am source (60 keV)
with activity of 37 MBq. The detector is operated at a single low-energy
threshold of about 5 keV.
Results:
At an FOV of 50
×
50 mm
2
: the background-subtracted sensitivi-
ty is 0.086 cps/kBq at 140 keV (w/1.9 mm pinhole) and the system spatial
resolution is 7.8 mm FWHM; at 60 keV, the sensitivity is 0.0025 cps/kBq
and the system spatial resolution is 4.2 mm FWHM (w/0.78 mm pinhole).
Larger sensitivity and spatial resolution were estimated with the use of the
coded aperture mask.
Conclusion:
The laboratory performance suggests the possibility to start
a clinical trial to evaluate the performance of MediPROBE for gamma-ray
nuclear imaging.
http://dx.doi.org/10.1016/j.ejmp.2016.01.360C.355
ABSOLUTE MEASUREMENT IN SITU OF THE 90Y ACTIVITY IN LIQUID
SOLUTION BY TDCR METHOD AND CALIBRATION OF AN IONIZATION
CHAMBER
S. Donatiello
* , a ,M. Capogni
b ,P. De Felic
e b ,V. Cannatà
a ,M. D’Arienzo
b ,L. Strigari
c ,M. Tapner
d .a
Enterprise Risk Management/Medical Physics,
Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy;
b
ENEA National Institute
of Ionizing Radiation Metrology (INMRI) Casaccia, Rome, Italy;
c
National Cancer
Institute Regina Elena, Rome, Italy;
d
Sirtex, Sydney, NSW, Australia
Aim:
One of the main problems in molecular radiation therapy is the ac-
curate determination of the activity of a radiopharmaceutical to be
administered to a patient for the cancer treatment. Usually commercially-
available radionuclide calibrators, based on a re-entrant 4pi ionization
chamber (IC), are used for this scope. These devices require in many cases
a calibration directly on site due to the short half-life of the radionu-
clides, typically used in nuclear medicine (NM), measured in them. In this
work the activity measurements directly in situ of a pure-beta short-
lived emitter of interest of NM, as the 90Y, are presented.
Materials and Methods:
A portable detector based on the ENEA-INMRI
Triple-to-Double Coincidence Ratio (TDCR) counter, equipped with the CAEN
Desktop DT5720B digitizer, was used at the Laboratory of Medical Physics
and Expert Systems IFO in Rome. The counter, made by three square Ha-
mamatsu photomultipliers arranged in a 120 degree planar geometry, was
used for direct activity measurements of a 90Y liquid solution, sent by Sirtex
to IFO, and to calibrate the IFO IC to 90Y. From the master solution two low-
activity samples were prepared in 20 mL glass vials containing radioactive
material in solution with 10 mL of Ultima Gold liquid scintillator; a high-
activity sample was also prepared ready-to-measure in the IFO IC.
Results:
The experimental data showed a good agreement between the ac-
tivity of the two samples directly measured on site by the TDCR; this allowed
the calibration of the IFO IC for 90Y in liquid solution with an uncertainty
by far within the limit of
±
10% established by the European Pharmacopoeia.
Conclusions:
A new method based on a portable TDCR device was tested
for direct activity measurements on site of a short-lived pure-beta emitter
used in NM. The IC at an NM site, as well as IFO, was then calibrated with
low uncertainty by using the previous standardized solution. This work was
carried out in the frame of the EMRP MetroMRT project.
http://dx.doi.org/10.1016/j.ejmp.2016.01.361C.356
A NOVEL RADIOGUIDED SURGERY TECHNIQUE EXPLOITING BETA –
DECAY
R. Donnarumma
* , a , b ,V. Bocci
a , b , c ,E. Capparella
a ,F. Collamati
a , b ,M. Cremonesi
d ,M.E. Ferrari
d ,F. Fioron
i e ,C.M. Gran
a d ,G. Ioannidi
s a ,M. Ior
i e ,G. Limiti
a , f ,C. Mancini Terracciano
a , b ,M. Marafini
b ,S. Morganti
a , b ,A. Russomand
o a , b , c ,E. Solfaroli Camilloc
i a , b ,M. Topp
i g ,G. Train
i a ,A. Versar
i e ,R. Faccini
a , b .a
Sapienza Universita di Roma, Roma, Italy;
b
INFN Sezione di Roma,
Roma, Italy;
c
Istituto Italiano di Tecnologia, Roma, Italy;
d
Istituto Europeo di
Oncologia, Milano, Italy;
e
IRCCS – ASMN, Reggio Emilia, Italy;
f
Istituto Superiore
di Sanità, Roma, Italy;
g
Laboratori Nazionali di Frascati dell’INFN, Frascati, Italy
e104
Abstracts/Physica Medica 32 (2016) e97–e115