Accurate Monte Carlo modeling and performance assessment of the X‐PET<sup>™</sup> subsystem of the FLEX Triumph<sup>™</sup> preclinical PET/CT scanner

Zeraatkar, Navid; Ay, Mohammad Reza; Kamali-Asl, Alireza; Zaidi, Habib

doi:10.1118/1.3547721

Cited by 16 publications

(9 citation statements)

References 26 publications

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“…An energy resolution of 25% for 511 keV photons was applied as blurring kernel for energies deposited within the crystals [25]. The LET was set to 250 keV whereas the higher energy threshold was set to 750 keV in all simulations.…”

Section: Methodsmentioning

confidence: 99%

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

Prasad

Zaidi

2012

Mol Imaging Biol

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PurposePositron emission tomography (PET) image quality deteriorates as the object size increases owing to increased detection of scattered and random events. The characterization of the scatter component in small animal PET imaging has received little attention owing to the small scatter fraction (SF) when imaging rodents. The purpose of this study is first to design and fabricate a cone-shaped phantom which can be used for measurement of object size-dependent SF and noise equivalent count rates (NECR), and second, to assess these parameters for two small animal PET scanners as function of radial offset, object size and lower energy threshold (LET).MethodsThe X-PET™ and LabPET-8™ scanners were modeled as realistically as possible using GATE Monte Carlo simulation platform. The simulation models were validated against experimental measurements in terms of sensitivity, SF and NECR. The dedicated phantom was fabricated in-house using high-density polyethylene. The optimized dimensions of the cone-shaped phantom are 158 mm (length), 20 mm (minimum diameter), 70 mm (maximum diameter) and taper angle of 9°.ResultsThe relative difference between simulated and experimental results for the LabPET-8™ scanner varied between 0.7% and 10% except for a few results where it was below 16%. Depending on the radial offset from the center of the central axial field-of-view (3–6 cm diameter), the SF for the cone-shaped phantom varied from 26.3% to 18.2%, 18.6 to 13.1% and 10.1 to 7.6% for the X-PET™, whereas it varied from 34.4% to 26.9%, 19.1 to 17.0% and 9.1 to 7.3% for the LabPET-8™, for LETs of 250, 350 and 425 keV, respectively. The SF increases as the radial offset decreases, LET decreases and object size increases. The SF is higher for the LabPET-8™ compared with the X-PET™ scanner. The NECR increases as the radial offset increases and object size decreases. The maximum NECR was obtained at a LET of 350 keV for the LabPET-8™ and 250 keV for the X-PET™. High correlation coefficients for SF and NECR were observed between the cone-shaped phantom and an equivalent volume cylindrical phantom for the three considered axial fields of view.ConclusionsA single cone-shaped phantom enables the assessment of the impact of three factors, namely radial offset, LET and object size on PET SF and count rate estimates. This phantom is more realistic owing to the non-uniform shape of rodents’ bodies compared to cylindrical uniform phantoms and seems to be well suited for evaluation of object size-dependent SF and NECR.

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Section: Methodsmentioning

confidence: 99%

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

Prasad

Zaidi

2012

Mol Imaging Biol

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“…It has been extensively validated and used in numerous projects to evaluate new PET scanner designs. [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] Without simulations, it is very challenging to explore new scanner designs, due to the cost and complexity of creating prototype systems intended solely for design evaluation purposes. AnnPET was modeled using the C-PET GATE scanner definition with a 6 ns coincidence timing window and 15% energy resolution; positron transport, Compton scattering, and photoelectric interactions were included in the model.…”

Section: Detector Geometry Definitionmentioning

confidence: 99%

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

et al. 2017

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Abstract. Positron emission tomography (PET) scanners designed for imaging of small animals have transformed translational research by reducing the necessity to invasively monitor physiology and disease progression. Virtually all of these scanners are based on the use of pixelated detector modules arranged in rings. This design, while generally successful, has some limitations. Specifically, use of discrete detector modules to construct PET scanners reduces detection sensitivity and can introduce artifacts in reconstructed images, requiring the use of correction methods. To address these challenges, and facilitate measurement of photon depth-ofinteraction in the detector, we investigated a small animal PET scanner (called AnnPET) based on a monolithic annulus of scintillator. The scanner was created by placing 12 flat facets around the outer surface of the scintillator to accommodate placement of silicon photomultiplier arrays. Its performance characteristics were explored using Monte Carlo simulations and sections of the NEMA NU4-2008 protocol. Results from this study revealed that AnnPET's reconstructed spatial resolution is predicted to be ∼1 mm full width at half maximum in the radial, tangential, and axial directions. Peak detection sensitivity is predicted to be 10.1%. Images of simulated phantoms (mini-hot rod and mouse whole body) yielded promising results, indicating the potential of this system for enhancing PET imaging of small animals.

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“…Alternative registration techniques could include extrinsic methods such as artificial external landmarks or intrinsic methods such as mutual information techniques [21], [22]. Alternatively, registration issues could be overcome by the use of dedicated small animal PET-CT-scanner where both modalities are incorporated in the same machine [23].…”

Section: Discussionmentioning

confidence: 99%

Combined Micro-PET/Micro-CT Imaging of Lung Tumours in SPC-raf and SPC-myc Transgenic Mice

et al. 2012

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IntroductionSPC-raf and SPC-myc transgenic mice develop disseminated and circumscribed lung adenocarcinoma respectively, allowing for assessment of carcinogenesis and treatment strategies. The purpose of this study was to investigate the technical feasibility, the correlation of initial findings to histology and the administered radiation dose of combined micro-PET/micro-CT in these animal models.Material and Methods14 C57BL/6 mice (4 nontransgenic, 4 SPC-raf transgenic, 6 SPC-myc transgenic) were examined using micro-CT and 18F-Fluoro-deoxyglucose micro-PET in-vivo. Micro-PET data was corrected for random events and scatter prior to reconstruction with a 3D-FORE/2D-OSEM iterative algorithm. Rigid micro-PET/micro-CT registration was performed. Tumour-to-non-tumour ratios were calculated for different lung regions and focal lesions. Diffuse tumour growth was quantified using a semiautomated micro-CT segmentation routine reported earlier. Regional histologic tumour load was assessed using a 4-point rating scale. Gamma radiation dose was determined using thermoluminescence dosimeters.ResultsMicro-CT allowed visualisation of diffuse and circumscribed tumours in SPC-raf and SPC-myc transgenic animals along with morphology, while micro-PET provided information on metabolism, but lacked morphologic detail. Mean tumour-to-non-tumour ratio was 2.47 for circumscribed lesions. No significant correlation could be shown between histological tumour load and tumour-to-nontumour ratio for diffuse tumours in SPC-raf transgenic animals. Calculation of the expected dose based on gamma dosimetry yielded approximately 140 mGy/micro-PET examination additional to approximately 200 mGy due to micro-CT.ConclusionsCombined micro-PET/micro-CT imaging allows for in-vivo assessment of lung tumours in SPC-raf and SPC-myc transgenic mice. The technique has potential for the evaluation of carcinogenesis and treatment strategies in circumscribed lung tumours.

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Accurate Monte Carlo modeling and performance assessment of the X‐PET^™ subsystem of the FLEX Triumph^™ preclinical PET/CT scanner

Cited by 16 publications

References 26 publications

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

Combined Micro-PET/Micro-CT Imaging of Lung Tumours in SPC-raf and SPC-myc Transgenic Mice

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Accurate Monte Carlo modeling and performance assessment of the X‐PET™ subsystem of the FLEX Triumph™ preclinical PET/CT scanner

Cited by 16 publications

References 26 publications

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

A Cone-Shaped Phantom for Assessment of Small Animal PET Scatter Fraction and Count Rate Performance

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

Combined Micro-PET/Micro-CT Imaging of Lung Tumours in SPC-raf and SPC-myc Transgenic Mice

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Accurate Monte Carlo modeling and performance assessment of the X‐PET^™ subsystem of the FLEX Triumph^™ preclinical PET/CT scanner