An On-Board Spectral-CT/CBCT/SPECT Imaging Configuration for Small-Animal Radiation Therapy Platform: A Monte Carlo Study

This study investigated the feasibility of a highly specific multiplexed image-guided small animal radiation therapy (SART) platform based on triple imaging from on-board single-photon emission computed tomography (SPECT), spectral-CT, and cone-beam CT (CBCT) guidance in radiotherapy treatment. As a proof-of-concept, the SART system was built with the capability of triple on-board image guidance by utilizing an x-ray tube and a single cadmium zinc telluride (CZT) semiconductor photon-counting imager via a Monte Carlo simulation study. The x-ray tube can be set at a low tube current for imaging mode and a high tube current for radiation therapy mode, respectively. In the imaging mode, both x-ray and gamma-ray projection data were collected by the imager to reconstruct CBCT, SPECT and spectral CT images of small animals being treated. The modulation transfer function (MTF) of the pixelated CZT imager measured was 8.6 lp/mm. The overall performances of the CBCT and SPECT imaging of the system were evaluated with sufficient spatial resolution and imaging quality to be fitted into the SART platform. The material differentiation and decomposition capacities of spectral CT within the system were verified using K-edge imaging, image-based optimal energy weighted imaging, and image-based linear material decomposition methods. The triple imaging capability of the system was demonstrated using a PMMA phantom containing gadolinium, iodine and radioisotope 99mTc inserts. All the probes were clearly identified in the registered image. The results demonstrated that a novel SART platform with high-quality on-board CBCT, spectral-CT, SPECT image guidance is technically feasible by using a single semiconductor imager, thus affording comprehensive image guidance from anatomical, functional, and molecular levels for radiation treatment beam delivery.

[1]  Erik Tryggestad,et al.  Small animal radiotherapy research platforms , 2011, Physics in medicine and biology.

[2]  Nesrin Dogan,et al.  Optical molecular imaging‐guided radiation therapy part 2: Integrated x‐ray and fluorescence molecular tomography , 2017, Medical physics.

[3]  Nigel G Anderson,et al.  Clinical applications of spectral molecular imaging: potential and challenges. , 2014, Contrast media & molecular imaging.

[4]  F Verhaegen,et al.  SpekCalc: a program to calculate photon spectra from tungsten anode x-ray tubes , 2009, Physics in medicine and biology.

[5]  H. Iida,et al.  Optimization of the width of the photopeak energy window in the TDCS technique for scatter correction in quantitative SPECT , 2004, IEEE Transactions on Nuclear Science.

[6]  Katsuyuki Taguchi,et al.  An analytical model of the effects of pulse pileup on the energy spectrum recorded by energy resolved photon counting x-ray detectors , 2010, Medical Imaging.

[7]  Taly Gilat Schmidt,et al.  Optimal "image-based" weighting for energy-resolved CT. , 2009, Medical physics.

[8]  Marios E Myronakis,et al.  Monte Carlo investigation of charge-transport effects on energy resolution and detection efficiency of pixelated CZT detectors for SPECT/PET applications. , 2010, Medical physics.

[9]  Anthonin Reilhac,et al.  Simulation-based evaluation of OSEM iterative reconstruction methods in dynamic brain PET studies , 2008, NeuroImage.

[10]  Kunio Doi,et al.  A simple method for determining the modulation transfer function in digital radiography , 1992, IEEE Trans. Medical Imaging.

[11]  F Verhaegen,et al.  Small animal image-guided radiotherapy: status, considerations and potential for translational impact. , 2015, The British journal of radiology.

[12]  J. Wong,et al.  Flat-panel cone-beam computed tomography for image-guided radiation therapy. , 2002, International journal of radiation oncology, biology, physics.

[13]  Nesrin Dogan,et al.  Optical molecular imaging‐guided radiation therapy part 1: Integrated x‐ray and bioluminescence tomography , 2017, Medical physics.

[14]  M. Khalil,et al.  Molecular SPECT Imaging: An Overview , 2011, International journal of molecular imaging.

[15]  Jianwen Luo,et al.  Spectral selective fluorescence molecular imaging with volume holographic imaging system , 2016 .

[16]  R. Chitkara,et al.  PET and SPECT in the management of lung cancer , 2002, Current opinion in pulmonary medicine.

[17]  Jeffrey A. Fessler,et al.  Application of trained Deep BCD-Net to iterative low-count PET image reconstruction , 2018, 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC).

[18]  Matthias Strassburg,et al.  CdTe/CZT under high flux irradiation , 2011 .

[19]  G Gang,et al.  Cascaded systems analysis of photon counting detectors. , 2014, Medical physics.

[20]  Baiyu Chen,et al.  Evaluation of conventional imaging performance in a research whole-body CT system with a photon-counting detector array , 2016, Physics in medicine and biology.

[21]  Nicola Tartoni,et al.  Study of charge-sharing in MEDIPIX3 using a micro-focused synchrotron beam , 2011 .

[22]  Donald W. Wilson,et al.  SemiSPECT: a small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays. , 2006, Medical physics.

[23]  B. Tsui,et al.  Evaluation of a Multi-pinhole Collimator for Imaging Small Animals with Different Sizes , 2012, Molecular Imaging and Biology.

[24]  Martin P Tornai,et al.  Implementation and CT sampling characterization of a third-generation SPECT–CT system for dedicated breast imaging , 2017, Journal of medical imaging.

[25]  M J Paulus,et al.  High resolution X-ray computed tomography: an emerging tool for small animal cancer research. , 2000, Neoplasia.

[26]  K. Taguchi,et al.  Vision 20/20: Single photon counting x-ray detectors in medical imaging. , 2013, Medical physics.

[27]  R. Baskar,et al.  Cancer and Radiation Therapy: Current Advances and Future Directions , 2012, International journal of medical sciences.

[28]  S Stute,et al.  GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy , 2011, Physics in medicine and biology.

[29]  E. Roessl,et al.  K-edge imaging in x-ray computed tomography using multi-bin photon counting detectors , 2007, Physics in medicine and biology.

[30]  Matthew D. Wilson,et al.  Investigating the small pixel effect in CdZnTe Hard X-ray detectors — The PIXIE ASIC , 2010, IEEE Nuclear Science Symposuim & Medical Imaging Conference.

[31]  Paul J Keall,et al.  Development of a micro-computed tomography-based image-guided conformal radiotherapy system for small animals. , 2010, International journal of radiation oncology, biology, physics.

[32]  Emily K. E. McCracken,et al.  Initial In Vivo Quantification of Tc-99m Sestamibi Uptake as a Function of Tissue Type in Healthy Breasts Using Dedicated Breast SPECT-CT , 2012, Journal of Oncology.

[33]  M. O’Connor,et al.  CZT detectors: How important is energy resolution for nuclear breast imaging? , 2006, Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics.

[34]  Nesrin Dogan,et al.  Bioluminescence Tomography Guided Small-Animal Radiation Therapy and Tumor Response Assessment. , 2018, International journal of radiation oncology, biology, physics.

[35]  Martin P. Tornai,et al.  Initial Evaluation of a Newly Developed High Resolution CT Imager for Dedicated Breast CT , 2012, Digital Mammography / IWDM.

[36]  Martin P Tornai,et al.  Characterization of simulated incident scatter and the impact on quantification in dedicated breast single-photon emission computed tomography , 2015, Journal of medical imaging.

[37]  Kevin J. Harrington,et al.  The tumour microenvironment after radiotherapy: mechanisms of resistance and recurrence , 2015, Nature Reviews Cancer.

[38]  K. Koral,et al.  Recovery of total I-131 activity within focal volumes using SPECT and 3D OSEM , 2007, Physics in medicine and biology.

[39]  I. Iordachita,et al.  Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation , 2015, Physics in medicine and biology.

[40]  Jan Sijbers,et al.  Reduction of ring artefacts in high resolution micro-CT reconstructions. , 2004, Physics in medicine and biology.

[41]  Karl Stierstorfer,et al.  Multi-energy performance of a research prototype CT scanner with small-pixel counting detector , 2013, Medical Imaging.

[42]  Ezio Caroli,et al.  Progress in the Development of CdTe and CdZnTe Semiconductor Radiation Detectors for Astrophysical and Medical Applications , 2009, Sensors.

[43]  P. Pretorius,et al.  SPECT/CT: an update on technological developments and clinical applications. , 2018, The British journal of radiology.

[44]  H. Hanaoka,et al.  Appropriate collimators in a small animal SPECT scanner with CZT detector , 2013, Annals of Nuclear Medicine.

[45]  J. Boone,et al.  Evaluation of the spatial resolution characteristics of a cone-beam breast CT scanner. , 2006, Medical physics.

[46]  P. Shikhaliev,et al.  Photon counting spectral CT versus conventional CT: comparative evaluation for breast imaging application , 2011, Physics in medicine and biology.

[47]  Yongmin Chang,et al.  Gadolinium oxide nanoparticles as potential multimodal imaging and therapeutic agents. , 2013, Current topics in medicinal chemistry.