مجال
التميز
|
تميز دراسي وبحثي
|
|
|
البحوث المنشورة
|
|
البحث (1):
|
|
عنوان البحث:
|
Evaluation
of XRI-UNO CdTe detector for nuclear medical imaging
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
22 June
2015
|
موجز عن البحث:
|
Over
the last two decades advances in semiconductor detector technology have
reached the point where they are sufficiently sensitive to become an
alternative to scintillators for high energy gamma ray detection for
application in fields such as medical imaging. This paper assessed the Cadmium-Telluride
(CdTe) XRI-UNO semiconductor detector produced by X-RAY Imatek for photon
energies of interest in nuclear imaging. The XRI-UNO detector was found to
have an intrinsic spatial resolution of <0.5mm and a high incident count
rate capability up to at least 1680cps. The system spatial resolution,
uniformity and sensitivity characteristics are also reported.
|
|
|
البحث (2):
|
|
عنوان البحث:
|
Lymphoscintigraphic
imaging study for quantitative evaluation of a small field of view (SFOV)
gamma camera
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
21 July
2015
|
موجز عن البحث:
|
The
Hybrid Compact Gamma Camera (HCGC) is a portable optical-gamma hybrid imager
designed for intraoperative medical imaging, particularly for sentinel lymph
node biopsy procedures. To investigate the capability of the HCGC in
lymphatic system imaging, two lymphoscintigraphic phantoms have been designed
and constructed. These phantoms allowed quantitative assessment and
evaluation of the HCGC for lymphatic vessel (LV) and sentinel lymph node
(SLN) detection. Fused optical and gamma images showed good alignment of the
two modalities allowing localisation of activity within the LV and the SLN.
At an imaging distance of 10 cm, the spatial resolution of the HCGC during
the detection process of the simulated LV was not degraded at a separation of
more than 1.5 cm (variation <5%) from the injection site (IS). Even in the
presence of the IS the targeted LV was detectable with an acquisition time of
less than 2 minutes. The HCGC could detect SLNs containing different
radioactivity concentrations (ranging between 1:20 to 1:100 SLN to IS
activity ratios) and under various scattering thicknesses (ranging between 5
mm to 30 mm) with high contrast-to-noise ratio (CNR) values (ranging between
11.6 and 110.8). The HCGC can detect the simulated SLNs at various IS to SLN
distances, different IS to SLN activity ratios and through varied scattering
medium thicknesses. The HCGC provided an accurate physical localisation of
radiopharmaceutical uptake in the simulated SLN. These characteristics of the
HCGC reflect its suitability for utilisation in lymphatic vessel drainage
imaging and SLN imaging in patients in different critical clinical situations
such as interventional and surgical procedures.
|
|
|
البحث (3):
|
|
عنوان البحث:
|
Investigation
of an SFOV hybrid gamma camera for thyroid imaging
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
06 January
2016
|
موجز عن البحث:
|
The Hybrid Compact Gamma Camera (HCGC) is a small
field of view (SFOV) portable hybrid gamma-optical camera intended for small
organ imaging at the patient bedside. In this study, a thyroid phantom was
used to determine the suitability of the HCGC for clinical thyroid imaging
through comparison with large field of view (LFOV) system performance. A
direct comparison with LFOV contrast performance showed that the lower
sensitivity of the HCGC had a detrimental effect on image quality. Despite
this, the contrast of HCGC images exceeded those of the LFOV cameras for some
image features particularly when a high-resolution pinhole collimator was
used. A clinical simulation showed that thyroid morphology was visible in a
5 min integrated image acquisition with an expected dependency on the
activity within the thyroid. The first clinical use of the HCGC for imaging
thyroid uptake of (123)I is also presented. Measurements indicate that the
HCGC has promising utility in thyroid imaging, particularly as its small size
allows it to be brought into closer proximity with a patient. Future
development of the energy response of the HCGC is expected to further improve
image detectability.
|
|
|
البحث (4):
|
|
عنوان البحث:
|
A novel
compact hybrid optical-gamma-camera: First clinical results
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
01 May 2016
|
موجز عن البحث:
|
Objectives: Hybrid imaging has proven to be a major
innovation in medical diagnosis. In nuclear medicine hybrid imaging allows
the fusion of functional information with anatomical detail, however clinical
studies have mainly been been carried out with large whole body scanning
instruments. We have developed and characterised a compact small field of
view hybrid camera of weight approximately 1kg. The camera consists of a
CsI(Tl) columnar scintillator coupled to an electron multiplying CCD. A
pinhole collimator coupled with a mirror and optical camera assembly provides
alignment of optical images within the same FOV as the gamma camera.
Methods: Eligible patients attending the nuclear
medicine clinic at Queen’s Medical Centre, Nottingham University Hospitals
NHS Trust, Nottingham were invited to take part according to ethical approval
by the UK National Research Ethics Committee (REC Ref No. 12/EM/0201). In
addition to routine imaging following the standard injection of the
radiopharmaceutical, hybrid planar images of the patient were acquired and
presented in a fused optical-gamma display.
Results: Patients undergoing routine imaging
procedures: with Tc-99m and I-123 were investigated. These included DatSCAN,
bone, thyroid, lachrimal drainage and lymphatic imaging. Initial
investigations of high resolution imaging using a 0.6mm crystal and 0.5mm pin
hole resulted in long acquisition times of over 5 minutes. Increasing the
thickness of the scintillator to 1.5mm and the diameter of the pin hole to
1mm improved the sensitivity, allowing images to be recorded within 5
minutes. Localisation of DatSCAN uptake in the striatum of patients was not
visualised using the thinner crystal and 0.5mm pin hole configuration,
however the small field of view system was well suited to small organ
imaging. Especially good results were achieved for lymphatic, thyroid and
lacrimal drainage studies, where the uptake could be clearly seen in relation
to the patient surface anatomy.
Conclusions: This clinical pilot study has
demonstrated the first results of clinical hybrid optical-gamma imaging in a
range of patients. Use of the system has raised new possibilities for small
organ imaging, where the localisation of radiopharmaceutical uptake can be
presented in an anatomical context using optical imaging. The compact nature
of the hybrid system offers the potential for bedside investigations and
further evaluation of the hybrid camera for intraoperative imaging in a
surgical theatre setting is underway.
|
|
|
البحث (5):
|
|
عنوان البحث:
|
Quantitative
investigation of a novel small field of view hybrid gamma camera (HGC)
capability for sentinel lymph node detection
|
رابط إلى البحث:
|
Click Here
|
تاريخ النشر:
|
09
September 2016
|
موجز عن البحث:
|
OBJECTIVE:
The hybrid gamma camera (HGC) has been developed to
enhance the localization of radiopharmaceutical uptake in targeted tissues
during surgical procedures such as sentinel lymph node (SLN) biopsy. To
assess the capability of the HGC, a lymph node contrast (LNC) phantom was
constructed to simulate medical scenarios of varying radioactivity
concentrations and SLN size.
METHODS:
The phantom was constructed using two clear acrylic
glass plates. The SLNs were simulated by circular wells of diameters ranging
from 10 to 2.5 mm (16 wells in total) in 1 plate. The second plate contains
four larger rectangular wells to simulate tissue background activity
surrounding the SLNs. The activity used to simulate each SLN ranged between 4
and 0.025 MBq. The activity concentration ratio between the background and
the activity injected in the SLNs was 1 : 10. The LNC phantom was placed at
different depths of scattering material ranging between 5 and 40 mm. The
collimator-to-source distance was 120 mm. Image acquisition times ranged from
60 to 240 s.
RESULTS:
Contrast-to-noise ratio analysis and
full-width-at-half-maximum (FWHM) measurements of the simulated SLNs were
carried out for the images obtained. Over the range of activities used, the
HGC detected between 87.5 and 100% of the SLNs through 20 mm of scattering
material and 75-93.75% of the SLNs through 40 mm of scattering material. The
FWHM of the detected SLNs ranged between 11.93 and 14.70 mm.
CONCLUSION:
The HGC is capable of detecting low accumulation of
activity in small SLNs, indicating its usefulness as an intraoperative
imaging system during surgical SLN procedures.
ADVANCES IN KNOWLEDGE:
This study investigates the capability of a novel
small-field-of-view (SFOV) HGC to detect low activity uptake in small SLNs.
The phantom and procedure described are inexpensive and could be easily
replicated and applied to any SFOV camera, to provide a comparison between
systems with clinically relevant results.
|
|
|
البحث (6):
|
|
عنوان البحث:
|
A
Multimodality Hybrid Gamma-Optical Camera for Intraoperative Imaging
|
رابط إلى البحث:
|
Click Here
|
تاريخ النشر:
|
09 March
2017
|
موجز عن البحث:
|
The development of low profile gamma-ray detectors
has encouraged the production of small field of view (SFOV) hand-held imaging
devices for use at the patient bedside and in operating theatres. Early
development of these SFOV cameras was focussed on a single modality—gamma ray
imaging. Recently, a hybrid system—gamma plus optical imaging—has been
developed. This combination of optical and gamma cameras enables high spatial
resolution multi-modal imaging, giving a superimposed scintigraphic and
optical image. Hybrid imaging offers new possibilities for assisting
clinicians and surgeons in localising the site of uptake in procedures such
as sentinel node detection. The hybrid camera concept can be extended to a
multimodal detector design which can offer stereoscopic images, depth
estimation of gamma-emitting sources, and simultaneous gamma and fluorescence
imaging. Recent improvements to the hybrid camera have been used to produce
dual-modality images in both laboratory simulations and in the clinic. Hybrid
imaging of a patient who underwent thyroid scintigraphy is reported. In
addition, we present data which shows that the hybrid camera concept can be
extended to estimate the position and depth of radionuclide distribution
within an object and also report the first combined gamma and Near-Infrared
(NIR) fluorescence images.
|
|
|
البحث (7):
|
|
عنوان البحث:
|
Capability
of a novel small field of view hybrid gamma camera (HGC) for sentinel lymph
node and small organ imaging
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
01 May 2017
|
موجز عن البحث:
|
Objectives: Small field of view gamma detection and
imaging technologies for monitoring in vivo tracer uptake are rapidly
expanding and being introduced for bed-side imaging and image guided surgical
procedures. The Hybrid Gamma Camera (HGC) has been developed to enhance the
localization of targeted radiopharmaceuticals during surgical procedures; for
example in sentinel lymph node (SLN) biopsies and for bed-side imaging in
procedures such as lacrimal drainage imaging and thyroid scanning. In this
study, a prototype anthropomorphic head and neck phantom has been designed,
constructed, and evaluated using representative modelled medical scenarios to
study the capability of the HGC to detect SLNs and image small organs.
Methods: An anthropomorphic head and neck phantom
has been designed to mimic the adult head and neck including some internal
organs and tissues of interest, such as the thyroid gland and sentinel lymph
nodes. The design of the head and neck phantom included an adjustable inner
jig holding the simulated SLNs and thyroid gland. The simulated thyroid gland
was designed and 3D printed taking into consideration the size and the shape
of a healthy adult thyroid gland. The inner sealed space of the thyroid was
filled with 15MBq of 99mTc through two upper filling valves. Sealed
micro-tubes (0.2ml) have been employed to simulate SLNs containing various
99mTc activity concentrations ranging between 0.1MBq and 1MBq, and can be
positioned at any desired place in the head and neck region. An active
background was simulated through mixing 10MBq of 99mTc solution with the
water used to fill the outer shell of the head and neck phantom.
Results: The head and neck phantom was employed to
simulate a situation where there are four SLNs distributed at two different
vertical levels and at two depths within the neck. Contrast to noise ratio
(CNR) calculations were performed for the detected SLNs at an 80mm distance
between both pinhole collimators (i.e. 0.5mm and 1.0mm diameters) and the
surface of the head and neck phantom with a 100s acquisition time. The
recorded CNR values for the simulated SLNs are higher when the HGC was fitted
with the 1.0mm diameter pinhole collimator. For instance, the recorded CNR
values for the superficially simulated SLN containing 0.1MBq of 99mTc using
0.5mm and 1.0mm diameter pinhole collimators are 6.48 and 16.42, respectively
(~87% difference). The anatomical context provided by the hybrid imaging
aided the localization process of radioactivity accumulation in simulated
SLNs. Gamma and hybrid optical images were acquired using the HGC with both
available pinhole collimators for the simulated thyroid gland. The thyroid
images produced varied in terms of spatial resolution and detectability. The
count profiles through the middle of the simulated thyroid gland images
provided by both pinhole collimators were obtained. The HGC could clearly
differentiate the individual peaks of both thyroid lobes in the gamma image
produced by the 0.5mm pinhole collimator. In contrast, the recorded count
profile for the acquired image using the 1.0mm diameter pinhole collimator
showed broader peaks for both lobes, reflecting the degradation of the spatial
resolution with increasing the diameter of the pinhole collimator.
Conclusion: The capability of the HGC has been
evaluated utilizing a prototype anthropomorphic head and neck phantom, and
the gamma and hybrid images obtained demonstrate that it is ideally suited
for intraoperative SLNs detection and small organ imaging. The
standardization of test phantoms and protocols for SFOV portable gamma
systems will provide an opportunity to collect data across various medical
centers and research groups. Moreover, it will provide a technical baseline
for researchers and clinical practitioners to consider when assessing their
SFOV gamma imaging systems. The anthropomorphic head and neck phantom
described is cost effective, reproducible, flexible and anatomically
representative.
|
|
|
البحث (8):
|
|
عنوان البحث:
|
A
hand-held hybrid gamma-near-infrared fluorescence imaging camera
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
01 May 2017
|
موجز عن البحث:
|
Objectives: Recently, there have been important
advances in the clinical application of targeted hybrid near-infrared (NIR)
fluorescent-radioactive tracers. ICG-99mTc-nanocolloid, for example, is
already being used by some centres for sentinel lymph node biopsy in head and
neck cancer. The radioactive component allows imaging at depths which would
not be possible with NIR alone and, once exposed, the NIR fluorescence
reporter can be imaged at very high resolution. Gamma detection is currently
carried out with a separate hand-held gamma camera or with a non-imaging
probe. Visualisation of NIR fluorescence during surgery requires a dedicated
NIR camera, several of which are available commercially. We describe a novel
hand-held hybrid NIR-gamma small field of view camera, capable of displaying
co-aligned images from both modalities, which can be fused into one image or
viewed separately. This study is a preliminary investigation of the
performance of the fluorescence component of this camera, including phantom
studies and first images from a preclinical pilot study.
Methods: The hybrid camera consists of a 1500 µm
thick thallium doped caesium iodide columnar (CsI:Tl) scintillator coupled to
an electron multiplying charged coupled device (EMCCD). A 1.0mm diameter
tungsten pinhole collimator gives a 40mm x 40mm nominal field of view for an
8mm x 8mm CCD detection area. A fluorescence camera was aligned to provide
the same field of view as the gamma camera with an LED ring as the excitation
source. The performance of the fluorescence imaging was quantified in this
study for the fluorophores ICG and IRDye800CW (CW800) using a range of
bespoke phantom experiments. In vivo images were also obtained from a
preclinical study of a targeted hybrid tracer (cRGD-CW800-TCO +
TCO-DOTA-111In) in mice with HT29 colorectal cancer xenografts. RESULTS AND
CONCLUSION: The portable hybrid camera prototype has been shown to
successfully image dual NIR-gamma tracers using both in vitro and in vivo
experimental models. With further development, this camera could be used
intraoperatively, offering the benefits of gamma imaging at depth in tissues
and high resolution surface NIR fluorescence imaging in a single imaging
system.
|
|
|
البحث (9):
|
|
عنوان البحث:
|
Design
and implementation of a prototype head and neck phantom for the performance
evaluation of gamma imaging systems
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
06 July
2017
|
موجز عن البحث:
|
Background
A prototype anthropomorphic head and neck phantom
has been designed to simulate the adult head and neck anatomy including some
internal organs and tissues of interest, such as thyroid gland and sentinel
lymph nodes (SLNs). The design of the head and neck phantom includes an inner
jig holding the simulated SLNs and thyroid gland. The thyroid gland structure
was manufactured using three-dimensional (3D) printing taking into
consideration the morphology and shape of a healthy adult thyroid gland.
Result
The head and neck phantom was employed to simulate a
situation where there are four SLNs distributed at two different vertical
levels and at two depths within the neck. Contrast to noise ratio (CNR)
calculations were performed for the detected SLNs at an 80 mm distance
between both pinhole collimators (0.5 and 1.0 mm diameters) and the surface
of the head and neck phantom with a 100 s acquisition time. The recorded CNR
values for the simulated SLNs are higher when the hybrid gamma camera (HGC)
was fitted with the 1.0 mm diameter pinhole collimator. For instance, the
recorded CNR values for the superficially simulated SLN (15 mm depth)
containing 0.1 MBq of 99mTc using 0.5 and 1.0 mm diameter pinhole collimators
are 6.48 and 16.42, respectively (~87% difference).
Gamma and hybrid optical images were acquired using
the HGC for the simulated thyroid gland. The count profiles through the
middle of the simulated thyroid gland images provided by both pinhole
collimators were obtained. The HGC could clearly differentiate the individual
peaks of both thyroid lobes in the gamma image produced by the 0.5-mm pinhole
collimator. In contrast, the recorded count profile for the acquired image
using the 1.0-mm-diameter pinhole collimator showed broader peaks for both
lobes, reflecting the degradation of the spatial resolution with increasing
the diameter of the pinhole collimator.
Conclusions
This anthropomorphic head and neck phantom provides
a valuable tool for assessing the imaging ability of gamma cameras used for
imaging the head and neck region. The standardisation of test phantoms for
SFOV gamma systems will provide an opportunity to collect data across various
medical centres. The phantom described is cost effective, reproducible,
flexible and anatomically representative.
|
|
|
البحث (10):
|
|
عنوان البحث:
|
A novel
compact small field of view hybrid gamma camera: first clinical results
|
رابط إلى البحث:
|
Click
Here
|
تاريخ النشر:
|
12 July
2017
|
موجز عن البحث:
|
Introduction
Hybrid imaging has proven to be a major innovation
in nuclear medicine, allowing the fusion of functional information with
anatomical detail. In the past, the use of hybrid imaging such as PET-CT,
PET-MRI and SPECT-CT has been of great clinical benefit; however, these
scanners are relatively large and bulky. We have developed and investigated
the clinical application of a compact small field of view hybrid gamma camera
(HGC) that is suitable for small-organ imaging at the patient bedside.
Patients and methods
The HGC – consisting of a CsI(Tl) scintillation
crystal coupled to an electron-multiplying charge-coupled device and an
optical camera – was used in this study. Eligible patients attending the
nuclear medicine clinic at Queen’s Medical Centre, Nottingham University
Hospitals NHS Trust, Nottingham, UK, were invited to take part in this study.
Following the standard injection of either a 99mTc-labelled or 123I-labelled
radiopharmaceutical, images of the patient were acquired using the HGC and presented
in a fused optical-gamma display.
Results
There were 24 patients enrolled in the study (age
range between 30 and 83 years, mean: 58.6 years), images of 18 of whom were
successfully acquired. These included patients who were undergoing bone,
thyroid, lacrimal drainage, DaTscan and lymphatic imaging. In general, the
small field of view system was well suited to small-organ imaging. The uptake
could be clearly seen in relation to the patient surface anatomy and showed
particular promise for lymphatic, thyroid and lacrimal drainage studies.
Conclusion
This pilot study has demonstrated the first clinical
results of hybrid optical-gamma imaging in patients. The use of this system
has raised new possibilities for small-organ imaging, in which the localization
of radiopharmaceutical uptake can be presented in an anatomical context using
optical imaging. The compact nature of the hybrid system offers the potential
for bedside investigations and intraoperative use.
|