Design, Development and Implementation of µSPC Phantom for
Quality Control in Micro-SPECT / CT and Micro-PET / CT Systems
Qualitative Study
Hatem Besbes
1
, Nejla Majoul
1
, Fatma Ben Hamida
1
and Philippe Choquet
2
1
Laboratory of Biophysics and Medical Technology, El Manar University, Tunis, Tunisia
2
Biophysics and Nuclear Medicine Service, Hautepierre Hospital, Strasbourg, France
Keywords: µSPC Phantom, Quality Control, Micro-SPECT/CT.
Abstract: The μSPC phantom is designed for the quality control of micro-SPECT/CT and micro-PET/CT systems.
However, it is an assembly of six patterns stored in a cylindrical box and enabling to control both micro-
SPECT unit in terms of uniformity, linearity and spatial resolution than micro-CT unit in terms of
uniformity , linearity, spatial resolution, diffusion rate, low contrast detectability, linearity of Hounsfield
coefficients and slice thickness. The construction material is plexiglass. As for the implementation, it was
made on a micro-SPECT/CT machine of the type "speCZT eXplore CT 120".
1 INTRODUCTION
Preclinical imaging has recently evolved
considerably, but it has only been concerned with
small animals (mice, rats...). The results obtained in
preclinical tests are extremely useful in the fields of
clinical imaging (Glover, 2010; Dillenseger, 2013;
Lina, 2009; Peremans, 2011) and pharmacology
((Matthews, 2013; Slavine, 2008). However, given
the size of these animals, the instruments used have
better imaging performance than those used for
humans.
The expected results of the images obtained are
so important that we must be quite demanding in
considering their qualities. The continuous
production of better qualities of these images is
ensured by the development of adequate quality
control protocols (Glover, 2010; Moran, 2011; Jan,
2006). These protocols are developed with
reference to quality control protocols already
adopted in clinical imaging.
The preclinical imaging techniques targeted by
this work are micro-SPECT / CT and micro-PET /
CT.
2 METHODS AND MATERIALS
For the design of our phantom we chose to work
with solid works software (Fig.1) because it’s easy
to use and to adapt.
When designing the μSPC phantom (Fig. 1), we
have tried to make sure that it allows checking the
majority of quality parameters acquisition micro-
SPECT / CT and micro-PET / CT systems while
respecting the dimensions of acquisition areas
offered by each machine. For this, we have referred
to the NEMA accreditation for micro-SPECT and
micro-PET (Seret, 2011) and ACR accreditation for
micro-CT (Panetta, 2012) and we have fixed seven
quality control parameters that are uniformity
(micro-SPECT, micro-PET, micro-CT), linearity
(micro-SPECT, micro-PET, micro-CT), spatial
resolution (micro-SPECT, micro-PET, micro-CT),
diffusion profile (micro-CT), linearity coefficients
Hunsfield (micro-CT), low contrast detectability
(micro-CT) and thicknesses of slices (micro-CT).
As for the uniformity that can be measured
following an acquisition done on the homogeneous
solution, for each of the selected parameters we
designed a pattern enabling to evaluate it (Tab.1).
The patterns will be stored in a cylinder (part 1)
with sealing cover (parts 8, 9, 10, 11 and 12), which
are the body of the phantom (Fig. 1).
For the implementation of the μSPC phantom,
we made acquisitions on micro-SPECT/CT machine
of the type "speCZT eXplore CT 120" (GE
Healthcare) of the in vivo preclinical imaging
283
Besbes H., Majoul N., Ben Hamida F. and Choquet P..
Design, Development and Implementation of µSPC Phantom for Quality Control in Micro-SPECT / CT and Micro-PET / CT Systems - Qualitative Study.
DOI: 10.5220/0004915702830288
In Proceedings of the International Conference on Biomedical Electronics and Devices (BIODEVICES-2014), pages 283-288
ISBN: 978-989-758-013-0
Copyright
c
2014 SCITEPRESS (Science and Technology Publications, Lda.)
Figure 1: Conception of the μSPC phantom with SOLIDWORKS.
service in the Hospital Hautepierre of Strasbourg.
This camera is constituted by a micro-SPECT unit
and micro-CT unit. The detection head of the
micro-SPECT unit "eXplore speCZT" consists of
ten sensors plan CZT semiconductor having a
surface of 64 cm2 and 5 mm thick. The detectors
are stationary and located in form of decagon
around a rotating and interchangeable cylindrical
collimator (Fig. 4) ((Glover, 2010; Dillenseger,
2013; Hohui, 2010). As for the CT unit "Explore
CT 120", it is constituted by an X-ray high
efficiency tube of 5 kW whose voltage can vary
between 70 and 120 kV and is attached to a planar
array of CCD detectors 3500x2300. The X-ray
beam used for the micro-CT unit is conical
(Dillenseger, 2013).
For the realization of the phantom we used
essentially the Plexiglas which is cheaper than and
as efficient as plastic acrylate. When for machining
the various parts, we carefully performed on
conventional lathe and milling despite their small
size.
3 RESULTS
3.1 Realization of the µSPC Phantom
Figure 2: µSPC phantom.
According to the design, we realized the body of
the phantom that is a cylindrical enclosure with
sealed cover and with two holes for the introduction
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Table 1: Conception of patterns contained in the μSPC
phantom with SOLIDWORKS.
Parameter N° (fig.1) Pattern
Linearity (µPET,
µSPECT, µCT)
2
Spatial resolution
(µPET, µSPECT)
3
Spatial resolution and
diffusion profil (µCT)
4
Linearity of Hounsfield
coefficients (µCT).
5
Low contrast
detectability (µCT)
6
Slice thickness (µCT) 7
Figure 3: µSPC phantom body.
of solutions with contrast agents (Fig.3) and all the
patterns for control of various performances like
linearity, spatial resolution, diffusion profile,
Hounsfield coefficients linearity, low contrast
detectability and slice thickness measurements
(Fig.2, Tab.2).
Table 2: Patterns contained in the µSPC phantom.
Quality parameter Pattern
Linearity (µPET, µSPECT,
µCT)
Spatial resolution (µPET,
µSPECT)
Spatial resolution and
diffusion profil (µCT)
Linearity of Hounsfield
coefficients (µCT).
Low contrast detectability
(µCT)
Slice thickness (µCT)
3.2 Acquisitions
For the realization of the acquisitions on µSPC
phantom, we first filled it with a radioactive
solution (V = 11.5 cm
3
) made of demineralized and
degasified water (for 48 hours) + 1 drop of aqueous
eosin 2% + 0.1 ml of pertechnetate-99m solution
(activity = 4.10 mCi) + 1 drop of Iomeron 400.
After filling the phantom, we placed it in the tunnel
of the machine.
The micro-CT acquisitions concerned the
linearity, the diffusion profile, the linearity of
Hounsfield coefficients, the slice thickness, the low
contrast detectability and the uniformity (Tab.3).
Design,DevelopmentandImplementationofµSPCPhantomforQualityControlinMicro-SPECT/CTandMicro-PET/
CTSystems-QualitativeStudy
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Table 3: Micro-CT Acquisitions.
Quality parameter Acquisition
Linearity
Linearity of Hounsfield
coefficients
Low contraste detectability
Diffusion profile
Slice thickness
Uniformity
The micro-SPECT and micro-SPECT/CT
acquisitions concerned linearity, uniformity and
spatial resolution (Tab.4).
Micro-SPECT/CT acquisitions are made
following the micro-CT acquisitions. Indeed, it
comes to be positioned on the micro-CT
acquisitions for achieving the micro-SPECT
acquisitions, and then we proceed with image
fusions. Thus, we were able to test micro-
SPECT/CT images for uniformity, linearity and
spatial resolution (Tab.5).
Table 4: Micro-SPECT Acquisitions.
Quality parameter Acquisition
Linearity
Spatial resolution
Uniformity
Table 5: Micro-SPECT/CT Acquisitions.
Quality parameter Acquisition
Linearity
Spatial resolution
Uniformity
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4 DISCUSSION
Knowing that we have worked on a new machine,
we found that it presents qualitatively very good
quality in terms of acquisition micro-SPECT.
Our μSPC phantom allowed, simultaneously,
the quality control of the micro-SPECT unit and the
micro-CT unit and consequently the whole of
micro-SPECT/CT system. Indeed, for the micro-
SPECT unit, we found that the spatial resolution is
close to 1mm as we distinguished a boundary
separation between the images of the two holes of
1mm diameter and separated by a distance also
1mm (Tab.4). In addition we have seen qualitatively
the presence of geometric distortions (Tab.4). As
for uniformity, we observed an artifact caused by
the presence of air bubbles (Tab.4).
At the micro-CT acquisitions, we have tested the
linearity of this unit (Tab.3), where the diffusion
profile, it is very easy to measure on the image of
Table 3 and in terms of the uniformity it is still easy
to calculate on the image of the same table. While
the study of the linearity coefficients of Hounsfield
(Tab.3) is clearly measurable for air, Teflon and
polyethylene, it is not the same for water because of
the presence of contrast agent (Iomeron 400). The
same thing for the low contrast detectability
(Tab.3), the Iomeron 400 increased shift of X-ray
attenuation rate between the Plexiglas and the
solution what makes the condition of low water-
Plexiglas contrast (Fig.4) is no longer there where it
is convenient to work without contrast agent. On the
other hand, to measure the slice thickness, low
contrast with water gives results with more
uncertainty (Fig.4) so that the results of this side are
better with the contrast agents (Tab.3).
Figure 4: Image test for slice thickness in micro CT
without Iomeron 400.
For micro-SPECT/CT acquisitions, we have noticed
that uniformity parameter is rather imposed by
micro-SPECT unit (Tab.4) which present
morphologically weaker qualities compared to
micro-CT. The same applies to geometric
distortions, they are more pronounced in the figure
in Table 5. Regarding the spatial resolution of the
whole system, it is better than 1mm because the
fusion with micro-CT can improve this quality.
If you do not see the test results of the spatial
resolution micro-CT, it is because the needle of the
test was broken when filling the phantom at
Hautepierre hospital.
5 CONCLUSIONS
This work has allowed us to offer to the practitioner
a new tool to better validate their results. Indeed,
μSPC the phantom we realized present very
interesting qualities because it allows to measure
the fundamental parameters of quality whatever for
micro-SPECT / CT or micro-PET / CT as the spatial
resolution and linearity.
The dimensions of the field of view that differ
from one device to another may or may not allow us
to add a test pattern contrast especially for devices
with a micro-PET unit. Moreover, we can achieve
as an accessory that can mount or dismount
depending on types of machines.
REFERENCES
Dillenseger, J. P., Guillaud, B., Goetz, C., Sayeh, A.,
Schimpf, R., Constantinesco, A., Choquet, P., 2013.
Coregistration of data sets from a micro-SPECT/CT
and a preclinical 1.5T MRI, Nuclear Instruments and
Methods in Physics Research A 702(2013)144–147.
Glover, D. K., Kundu, B., Schelbert, H. R., 2010.
Chapter11: State-of-the-Art Instrumentation for PET
and SPECT Imaging in Small Animals; Clinical
nuclear cardiology, state of the art and future
directions, MOSBY, ELSEVIER.
Hohui, H., Ingtsung, H., 2010. Image Reconstructions
from Limit Views and Angle Coverage Data for a
Stationary Multi-Pinhole SPECT System,
TSINGHUA SCIENCE AND TECHNOLOGY ISSNl
l1007-0214l l07/20l lpp44-49 Volume 15, Number 1.
Jan, M., Ni, Y., Chen, K., Liang, H. Chuang, K., Fu, Y.,
2006. A combined micro-PET/CT scanner for small
animal imaging, Nuclear Instruments and Methods in
Physics Research A 569, 314–318.
Lina, K., Liu, H., Hsu, P., Chung, Y., Huang, W., Chen,
J., Wey, S., Yen, T., Hsiao, I., 2009. Quantitative
micro-SPECT/CT for detecting focused ultrasound-
Design,DevelopmentandImplementationofµSPCPhantomforQualityControlinMicro-SPECT/CTandMicro-PET/
CTSystems-QualitativeStudy
287
induced blood–brain barrier opening in the rat,
Nuclear Medicine and Biology 36, 853–861.
Matthews, P. M., Coatney, R., Alsaid, H., Jucker, B.,
Ashworth, S., Parker, C., Changani, K., 2013.
Technologies: preclinical imaging for drug
development, Drug Discovery Today: Technologies |
Translational Pharmacology: From Animal to Man
and Back Vol. 10, No. 3, 343-350.
Moran, C. M., Pye, S. D., Ellis, W., Janeczko, A., Morris,
K. D., Mcneilly, A. S., Fraser, H. M., 2011. A
comparison of the imaging performance of high
resolution ultrasound scanners for preclinical
imaging, Ultrasound in Med. & Biol., Vol. 37, No. 3,
pp. 493–501.
Panetta, D., Belcari, N., Del Guerra, A., Bartolomei, A.,
Salvadori, P. A., 2012. Analysis of image sharpness
reproducibility on a novel engineered micro-CT
scanner with variable geometry and embedded
recalibration software, Physica Medica 28, 166-173.
Peremans, K., Vermeire, S., Dobbeleir, A., Gielen, I.,
Samoy, Y., Piron, K., Vandermeulen, E., Slegers, G.,
van Bree, H., De Spiegeleer , B., Dik, K., 2011.
Recognition of anatomical predilection sites in canine
elbow pathology on bone scans using micro-single
photon emission tomography, The Veterinary Journal
188 64–72.
Seret, A., 2011. NEMA NU1-2001 performance tests of
four Philips Brightview cameras, Nuclear Instruments
and Methods in Physics Research A 648, 589–592.
Slavine, N. V., Antich, P. P., 2008. Practical method for
radioactivity distribution analysis in small-animal
PET cancer studies, Applied Radiation and Isotopes
66, 1861– 1869.
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