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Han H, Geng C, Deng X, Li J, Shu D, Tang X. A preliminary study of multispectral Cherenkov imaging and a Fricke-xylenol orange gel film (MCIFF) for online, absolute dose measurement. Med Phys 2024; 51:3734-3745. [PMID: 38224326 DOI: 10.1002/mp.16942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/17/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Cherenkov luminescence imaging has shown potential for relative dose distribution and field verification in radiation therapy. However, to date, limited research utilizing Cherenkov luminescence for absolute dose calibration has been conducted owing to uncertainties arising from camera positioning and tissue surface optical properties. PURPOSE This paper introduces a novel approach to multispectral Cherenkov luminescence imaging combined with Fricke-xylenol orange gel (FXG) film, termed MCIFF, which can enable online full-field absolute dose measurement. By integrating these two approaches, MCIFF allows for calibration of the ratio between two spectral intensities with absorbed dose, thereby enabling absolute dose measurement. METHODS All experiments are conducted on a Varian Clinac 23EX, utilizing an electron multiplying charge-coupled device (EMCCD) camera and a two-way image splitter for simultaneous capture of two-spectral Cherenkov imaging. In the first part of this study, the absorbance curves of the prepared FXG film, which receives different doses, are measured using a fluorescence spectrophotometer to verify the correlation between absorbance and dose. In the second part, the FXG film is positioned directly under the radiation beam to corroborate the dose measurement capacity of MCIFF across various beams. In the third part, the feasibility of MCIFF is tested in actual radiotherapy settings via a humanoid model, demonstrating its versatility with various radiotherapy materials. RESULTS The results of this study indicate that the logarithmic ratios of spectral intensities at wavelengths of 550 ± 50 and 700 ± 100 nm accurately reflect variations in radiation dose (R2 > 0.96) across different radiation beams, particle energies, and dose rates. The slopes of the fitting lines remain consistent under varying beam conditions, with discrepancies of less than 8%. The optical profiles obtained using the MCIFF exhibit a satisfactory level of agreement with the measured results derived from the treatment planning system (TPS) and EBT3 films. Specifically, for photon beams, the lateral distances between the 80% and 20% isodose lines, referred to as the penumbra (P80-20) values, obtained through TPS, EBT3 films, and MCIFF, are determined as 0.537, 0.664, and 0.848 cm, respectively. Similarly, for electron beams, the P80-20 values obtained through TPS, EBT3 films, and MCIFF are found to be 0.432, 0.561, and 0.634 cm, respectively. Furthermore, imaging of the anthropomorphic phantom demonstrates the practical application of MCIFF in real radiotherapy environments. CONCLUSION By combining an FXG film with Cherenkov luminescence imaging, MCIFF can calibrate Cherenkov luminescence to absorbed dose, filling the gap in online 2D absolute dose measurement methods in clinical practice, and providing a new direction for the clinical application of optical imaging to radiation therapy.
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Affiliation(s)
- Haonan Han
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Changran Geng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xinping Deng
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Jun Li
- Radiotherapy Center, Subei People's Hospital of Jiangsu Province, Yangzhou, People's Republic of China
| | - Diyun Shu
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
| | - Xiaobin Tang
- Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
- Key Laboratory of Nuclear Technology Application and Radiation Protection in Astronautic, Nanjing University of Aeronautics and Astronautics, Ministry of Industry and Information Technology, Nanjing, People's Republic of China
- Joint International Research Laboratory on Advanced Particle Therapy, Nanjing University of Aeronautics and Astronautics, Nanjing, People's Republic of China
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Petusseau AF, Streeter SS, Ulku A, Feng Y, Samkoe KS, Bruschini C, Charbon E, Pogue BW, Bruza P. Subsurface fluorescence time-of-flight imaging using a large-format single-photon avalanche diode sensor for tumor depth assessment. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:016004. [PMID: 38235320 PMCID: PMC10794045 DOI: 10.1117/1.jbo.29.1.016004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024]
Abstract
Significance Fluorescence guidance is used clinically by surgeons to visualize anatomical and/or physiological phenomena in the surgical field that are difficult or impossible to detect by the naked eye. Such phenomena include tissue perfusion or molecular phenotypic information about the disease being resected. Conventional fluorescence-guided surgery relies on long, microsecond scale laser pulses to excite fluorescent probes. However, this technique only provides two-dimensional information; crucial depth information, such as the location of malignancy below the tissue surface, is not provided. Aim We developed a depth sensing imaging technique using light detection and ranging (LiDAR) time-of-flight (TOF) technology to sense the depth of target tissue while overcoming the influence of tissue optical properties and fluorescent probe concentration. Approach The technology is based on a large-format (512 × 512 pixel ), binary, gated, single-photon avalanche diode (SPAD) sensor with an 18 ps time-gate step, synchronized with a picosecond pulsed laser. The fast response of the sensor was developed and tested for its ability to quantify fluorescent inclusions at depth and optical properties in tissue-like phantoms through analytical model fitting of the fast temporal remission data. Results After calibration and algorithmic extraction of the data, the SPAD LiDAR technique allowed for sub-mm resolution depth sensing of fluorescent inclusions embedded in tissue-like phantoms, up to a maximum of 5 mm in depth. The approach provides robust depth sensing even in the presence of variable tissue optical properties and separates the effects of fluorescence depth from absorption and scattering variations. Conclusions LiDAR TOF fluorescence imaging using an SPAD camera provides both fluorescence intensity images and the temporal profile of fluorescence, which can be used to determine the depth at which the signal is emitted over a wide field of view. The proposed tool enables fluorescence imaging at a higher depth in tissue and with higher spatial precision than standard, steady-state fluorescence imaging tools, such as intensity-based near-infrared fluorescence imaging, optical coherence tomography, Raman spectroscopy, or confocal microscopy. Integration of this technique into a standard surgical tool could enable rapid, more accurate estimation of resection boundaries, thereby improving the surgeon's efficacy and efficiency, and ultimately improving patient outcomes.
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Affiliation(s)
- Arthur F Petusseau
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
| | - Samuel S Streeter
- Geisel School of Medicine at Dartmouth, Department of Orthopaedics, Hanover, New Hampshire, United States
| | - Arin Ulku
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Yichen Feng
- Geisel School of Medicine at Dartmouth, Department of Surgery, Hanover, New Hampshire, United States
| | - Kimberley S Samkoe
- Geisel School of Medicine at Dartmouth, Department of Surgery, Hanover, New Hampshire, United States
| | - Claudio Bruschini
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Edoardo Charbon
- Ecole polytechnique fédérale de Lausanne, Advanced Quantum Architecture Laboratory, Neuchâtel, Switzerland
| | - Brian W Pogue
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
- University of Wisconsin-Madison, Department of Medical Physics, Madison, Wisconsin, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering and Dartmouth Cancer Center, Hanover, New Hampshire, United States
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Jia M, Sun B, Wang Y, Gao F, Yuan Z, Pogue BW. Photon-limited Cherenkov imaging of radiation therapy dose. OPTICS LETTERS 2023; 48:1918-1921. [PMID: 37221799 PMCID: PMC10914388 DOI: 10.1364/ol.485668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 02/24/2023] [Indexed: 05/25/2023]
Abstract
Cherenkov imaging is a unique verification tool that could provide both dosimetric and tissue functional information during radiation therapy. However, the number of interrogated Cherenkov photons in tissue is always limited and tangled with stray radiation photons, severely frustrating the measurement the signal-to-noise ratio (SNR). As such, here, a noise-robust photon-limited imaging technique is proposed by comprehensively exploiting the physical rationale of low-flux Cherenkov measurements together with the spatial correlations of the objects. Validation experiments confirmed that the Cherenkov signal could be promisingly recovered with high SNR by irradiating at as few as one x ray pulse from a linear accelerator (10 mGy dose), and the Cherenkov excited luminescence imaging depth can be extended by >100% on average, for most concentrations of phosphorescent probe. This approach demonstrates that improved applications in radiation oncology could be seen when signal amplitude, noise robustness, and temporal resolution are comprehensively considered in the image recovery process.
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Affiliation(s)
- Mengyu Jia
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Boshuai Sun
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Yuxia Wang
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Feng Gao
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Tianjin Key Laboratory of Biomedical Detecting techniques and Instruments, Tianjin 300072, China
| | - Zhiyong Yuan
- Department of Radiation Oncology, Tianjin Medical University Cancer Institute & Hospital, Tianjin 300060, China
- Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
- National Clinical Research Center for Cancer, Tianjin 300060, China
| | - Brian W. Pogue
- Department of Medical Physics, University of Wisconsin-Madison, Madison WI 53705, USA
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, USA
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Zhang W, Hu T, Li Z, Sun Z, Jia K, Dou H, Feng J, Pogue BW. Selfrec-Net: self-supervised deep learning approach for the reconstruction of Cherenkov-excited luminescence scanned tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:783-798. [PMID: 36874507 PMCID: PMC9979688 DOI: 10.1364/boe.480429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/23/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
As an emerging imaging technique, Cherenkov-excited luminescence scanned tomography (CELST) can recover a high-resolution 3D distribution of quantum emission fields within tissue using X-ray excitation for deep penetrance. However, its reconstruction is an ill-posed and under-conditioned inverse problem because of the diffuse optical emission signal. Deep learning based image reconstruction has shown very good potential for solving these types of problems, however they suffer from a lack of ground-truth image data to confirm when used with experimental data. To overcome this, a self-supervised network cascaded by a 3D reconstruction network and the forward model, termed Selfrec-Net, was proposed to perform CELST reconstruction. Under this framework, the boundary measurements are input to the network to reconstruct the distribution of the quantum field and the predicted measurements are subsequently obtained by feeding the reconstructed result to the forward model. The network was trained by minimizing the loss between the input measurements and the predicted measurements rather than the reconstructed distributions and the corresponding ground truths. Comparative experiments were carried out on both numerical simulations and physical phantoms. For singular luminescent targets, the results demonstrate the effectiveness and robustness of the proposed network, and comparable performance can be attained to a state-of-the-art deep supervised learning algorithm, where the accuracy of the emission yield and localization of the objects was far superior to iterative reconstruction methods. Reconstruction of multiple objects is still reasonable with high localization accuracy, although with limits to the emission yield accuracy as the distribution becomes more complex. Overall though the reconstruction of Selfrec-Net provides a self-supervised way to recover the location and emission yield of molecular distributions in murine model tissues.
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Affiliation(s)
- Wenqian Zhang
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Ting Hu
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Zhe Li
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Zhonghua Sun
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Kebin Jia
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Huijing Dou
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
| | - Jinchao Feng
- Beijing Key Laboratory of Computational Intelligence and Intelligent System, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- Beijing Laboratory of Advanced Information Networks, Beijing 100124, China
| | - Brian W. Pogue
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705, USA
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Pogue BW, Zhang R, Cao X, Jia JM, Petusseau A, Bruza P, Vinogradov SA. Review of in vivo optical molecular imaging and sensing from x-ray excitation. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200308VR. [PMID: 33386709 PMCID: PMC7778455 DOI: 10.1117/1.jbo.26.1.010902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/24/2020] [Indexed: 05/05/2023]
Abstract
SIGNIFICANCE Deep-tissue penetration by x-rays to induce optical responses of specific molecular reporters is a new way to sense and image features of tissue function in vivo. Advances in this field are emerging, as biocompatible probes are invented along with innovations in how to optimally utilize x-ray sources. AIM A comprehensive review is provided of the many tools and techniques developed for x-ray-induced optical molecular sensing, covering topics ranging from foundations of x-ray fluorescence imaging and x-ray tomography to the adaptation of these methods for sensing and imaging in vivo. APPROACH The ways in which x-rays can interact with molecules and lead to their optical luminescence are reviewed, including temporal methods based on gated acquisition and multipoint scanning for improved lateral or axial resolution. RESULTS While some known probes can generate light upon x-ray scintillation, there has been an emergent recognition that excitation of molecular probes by x-ray-induced Cherenkov light is also possible. Emission of Cherenkov radiation requires a threshold energy of x-rays in the high kV or MV range, but has the advantage of being able to excite a broad range of optical molecular probes. In comparison, most scintillating agents are more readily activated by lower keV x-ray energies but are composed of crystalline inorganic constituents, although some organic biocompatible agents have been designed as well. Methods to create high-resolution structured x-ray-optical images are now available, based upon unique scanning approaches and/or a priori knowledge of the scanned x-ray beam geometry. Further improvements in spatial resolution can be achieved by careful system design and algorithm optimization. Current applications of these hybrid x-ray-optical approaches include imaging of tissue oxygenation and pH as well as of certain fluorescent proteins. CONCLUSIONS Discovery of x-ray-excited reporters combined with optimized x-ray scan sequences can improve imaging resolution and sensitivity.
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Affiliation(s)
- Brian W. Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States
| | - Xu Cao
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Jeremy Mengyu Jia
- Stanford University School of Medicine, Department of Radiation Oncology, Palo Alto, California, United States
| | - Arthur Petusseau
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts of Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
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Cao X, Jiang S, Gunn JR, Bruza P, Pogue BW. Single pixel hyperspectral Cherenkov-excited fluorescence imaging with LINAC X-ray sheet scanning and spectral unmixing. OPTICS LETTERS 2020; 45:6130-6133. [PMID: 33186932 DOI: 10.1364/ol.401286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Cherenkov light induced from megavolt (MV) X-rays during external beam radiotherapy serves as an internal light source to excite phosphors or fluorophores within biological tissues for molecular imaging. The broad spectrum of Cherenkov light leads to significant spectral overlap with any luminescence emission and, to overcome this problem, a single pixel hyperspectral imaging methodology was demonstrated here by coupling the detection with light sheet scanning and filtered back projection reconstruction of hyperspectral images. Thin scanned sheets of MV X-rays produce Cherenkov light to illuminate the planes deep within the tissue-simulating media. A fluorescence probe was excited by Cherenkov light, and a complete hyperspectral sinogram of the data was obtained through translation and rotation of the beam. Hyperspectral 2D images finally were reconstructed. Through this approach of spectral unmixing, it was possible to resolve hyperspectral images of both the Cherenkov and resulting fluorescence intensity from molecular sensors.
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LaRochelle EPM, Pogue BW. Theoretical lateral and axial sensitivity limits and choices of molecular reporters for Cherenkov-excited luminescence in tissue during x-ray beam scanning. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200235R. [PMID: 33185051 PMCID: PMC7658603 DOI: 10.1117/1.jbo.25.11.116004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/21/2020] [Indexed: 05/03/2023]
Abstract
PURPOSE Unlike fluorescence imaging utilizing an external excitation source, Cherenkov emissions and Cherenkov-excited luminescence occur within a medium when irradiated with high-energy x-rays. Methods to improve the understanding of the lateral spread and axial depth distribution of these emissions are needed as an initial step to improve the overall system resolution. METHODS Monte Carlo simulations were developed to investigate the lateral spread of thin sheets of high-energy sources and compared to experimental measurements of similar sources in water. Additional simulations of a multilayer skin model were used to investigate the limits of detection using both 6- and 18-MV x-ray sources with fluorescence excitation for inclusion depths up to 1 cm. RESULTS Simulations comparing the lateral spread of high-energy sources show approximately 100 × higher optical yield from electrons than photons, although electrons showed a larger penumbra in both the simulations and experimental measurements. Cherenkov excitation has a roughly inverse wavelength squared dependence in intensity but is largely redshifted in excitation through any distance of tissue. The calculated emission spectra in tissue were convolved with a database of luminescent compounds to produce a computational ranking of potential Cherenkov-excited luminescence molecular contrast agents. CONCLUSIONS Models of thin x-ray and electron sources were compared with experimental measurements, showing similar trends in energy and source type. Surface detection of Cherenkov-excited luminescence appears to be limited by the mean free path of the luminescence emission, where for the given simulation only 2% of the inclusion emissions reached the surface from a depth of 7 mm in a multilayer tissue model.
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Affiliation(s)
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, United States
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Cao X, Allu SR, Jiang S, Gunn Bs JR, Yao PhD C, Xin PhD J, Bruza PhD P, Gladstone ScD DJ, Jarvis Md PhD LA, Tian PhD J, Swartz Md Msph PhD HM, Vinogradov PhD SA, Pogue PhD BW. High-Resolution pO 2 Imaging Improves Quantification of the Hypoxic Fraction in Tumors During Radiation Therapy. Int J Radiat Oncol Biol Phys 2020; 109:603-613. [PMID: 33002542 DOI: 10.1016/j.ijrobp.2020.09.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/14/2020] [Accepted: 09/21/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE The extreme microscopic heterogeneity of tumors makes it difficult to characterize tumor hypoxia. We evaluated how changes in the spatial resolution of oxygen imaging could alter measures of tumor hypoxia and their correlation to radiation therapy response. METHODS AND MATERIALS Cherenkov-Excited Luminescence Imaging in combination with an oxygen probe, Oxyphor PtG4 was used to directly image tumor pO2 distributions with 0.2 mm spatial resolution at the time of radiation delivery. These pO2 images were analyzed with variations of reduced spatial resolution from 0.2 mm to 5 mm, to investigate the influence of how reduced imaging spatial resolution would affect the observed tumor hypoxia. As an in vivo validation test, mice bearing tumor xenografts were imaged for hypoxic fraction and median pO2 to examine the predictive link with tumor response to radiation therapy, while accounting for spatial resolution. RESULTS In transitioning from voxel sizes of 200 μm to 3 mm, the median pO2 values increased by a few mm Hg, and the hypoxic fraction decreased by more than 50%. When looking at radiation-responsive tumors, the median pO2 values changed just a few mm Hg as a result of treatment, and the hypoxic fractions changed by as much as 50%. This latter change, however, could only be seen when sampling was performed with high spatial resolution. Median pO2 or similar quantities obtained from low resolution measurements are commonly used in clinical practice, however these parameters are much less sensitive to changes in the tumor microenvironment than the tumor hypoxic fraction obtained from high-resolution oxygen images. CONCLUSIONS This study supports the hypothesis that for adequate measurements of the tumor response to radiation therapy, oxygen imaging with high spatial resolution is required to accurately characterize the hypoxic fraction.
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Affiliation(s)
- Xu Cao
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Xidian University, Engineering Research Center of Molecular & Neuroimaging, Ministry of Education, School of Life Science and Technology, Xi'an, Shaanxi, China
| | - Srinivasa Rao Allu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School or Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Shudong Jiang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Jason R Gunn Bs
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire
| | - Cuiping Yao PhD
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Xi'an Jiaotong University, Institute of Biomedical Analytical Technology and Instrumentation, School of Life Science and Technology, Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an, Shaanxi, China
| | - Jing Xin PhD
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Xi'an Jiaotong University, Institute of Biomedical Analytical Technology and Instrumentation, School of Life Science and Technology, Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an, Shaanxi, China
| | - Petr Bruza PhD
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire
| | - David J Gladstone ScD
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Lesley A Jarvis Md PhD
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Jie Tian PhD
- Xidian University, Engineering Research Center of Molecular & Neuroimaging, Ministry of Education, School of Life Science and Technology, Xi'an, Shaanxi, China; CAS Key Laboratory of Molecular Imaging, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | | | - Sergei A Vinogradov PhD
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Chemistry, School or Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brian W Pogue PhD
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire.
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Brůža P, Pétusseau A, Tisa S, Jermyn M, Jarvis LA, Gladstone DJ, Pogue BW. Imaging Cherenkov photon emissions in radiotherapy with a Geiger-mode gated quanta image sensor. OPTICS LETTERS 2019; 44:4546-4549. [PMID: 31517927 PMCID: PMC7181332 DOI: 10.1364/ol.44.004546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
The emission of Cherenkov photons from human and animal tissue can be observed during clinical x-ray or particle beam irradiation. However, imaging this weak emission with the necessary single-photon sensitivity in the clinical room is challenging because of milliwatt-level ambient room lighting and the presence of stray high-energy radiation. In this Letter, we demonstrate, to the best of our knowledge, the first Cherenkov imaging with a time-gated quanta image sensor employing a large single-photon avalanche diode (SPAD) array. Detecting single Cherenkov photons was possible with high photon avalanche gain, fast temporal gating, and moderately high ∼7% photon detection probability. Single-bit digitization and active SPAD quenching enabled stray x-ray noise suppression and photon-noise-limited imaging in a clinical environment. This type of imaging allows the knowledge of location, shape, and surface dose of the therapeutic beam radiotherapy with the stability of solid state-based detection.
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Jia MJ, Bruza P, Andreozzi JM, Jarvis LA, Gladstone DJ, Pogue BW. Cherenkov-excited luminescence scanned imaging using scanned beam differencing and iterative deconvolution in dynamic plan radiation delivery in a human breast phantom geometry. Med Phys 2019; 46:3067-3077. [PMID: 30980725 DOI: 10.1002/mp.13545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 12/14/2022] Open
Abstract
PURPOSE The purpose of this study was to demonstrate high resolution optical luminescence sensing, referred to as Cherenkov excited luminescence scanning imaging (CELSI), could be achieved during a standard dynamic treatment plan for a whole breast radiotherapy geometry. METHODS The treatment plan beams induce Cherenkov light within tissue, and this excitation projects through the beam trajectory across the medium, inducing luminescence where there can be molecular reporter. Broad beams generally produce higher signal but low spatial resolution, yet for dynamic plans the scanning of the multileaf collimator allows for a beam-narrowing strategy by recursively temporal differencing each of the Cherenkov images and associated luminescence images. Then reconstruction from each of these size-reduced beamlets defined by the differenced Cherenkov images provides a well-conditioned matrix inversion, where the spatial frequencies are limited by the higher signal-to-noise ratio beamlets. A built-in stepwise convergence relies on stepwise beam size reduction, which is associated with a widening of the bandwidth of Cherenkov spatial frequency and resultant increase in spatial resolution. For the phantom experiments, europium nanoparticles were used as luminescent probes and embedded at depths ranging from 3 to 8 mm. An intensity modulated radiotherapy (IMRT) plan was used to test this. RESULTS The Cherenkov images spatially guided where the luminescence was measured from, providing high lateral resolution, and iterative reconstruction convergence showed that optimization of the initial and stopping beamlet widths could be achieved with 15 and 4.5 mm, respectively, using a luminescence imaging frame rate of 5/s. With the IMRT breast plan, the original lateral resolution was improved 2X, that is, 0.08-0.24 mm for target depths of 3-8 mm. In comparison, a dynamic wedge (DW) plan showed an inferior image fidelity, with relative contrast recovery decreasing from 0.86 to 0.79. The methodology was applied to a three-dimensional dataset to reconstruct Cherenkov excited luminescence intensity distributions showing volumetric recovery of a 0.5 mm diameter object composed of 0.5 μM luminescent microbeads. CONCLUSIONS High resolution CELSI was achieved with a clinical breast external beam radiotherapy (EBRT) plan. It is anticipated that this method can allow visualization and localization for luminescence/fluorescence tagged vasculature, lymph nodes, or superficial tagged regions with most dynamic treatment plans.
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Affiliation(s)
- Mengyu Jeremy Jia
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | | | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Norris Cotton Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.,Norris Cotton Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
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11
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Jia MJ, Cao X, Gunn JR, Bruza P, Jiang S, Pogue BW. Tomographic Cherenkov-excited luminescence scanned imaging with multiple pinhole beams recovered via back-projection reconstruction. OPTICS LETTERS 2019; 44:1552-1555. [PMID: 30933088 PMCID: PMC7104332 DOI: 10.1364/ol.44.001552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/16/2019] [Indexed: 05/22/2023]
Abstract
Cherenkov-excited luminescence scanned imaging (CELSI) is achieved with a clinical linear accelerator during external beam radiotherapy to map out molecular luminescence intensity or lifetime in tissue. In order to realize a deeper imaging depth with a reasonable spatial resolution in CELSI, we optimized the original scanning procedure to complete this in a way similar to x-ray computed tomography and with image reconstruction from maximum-likelihood expectation maximization and multi-pinhole irradiation for parallelization. Resolution phantom studies showed that a 0.3 mm diameter capillary tube containing 0.01 nM luminescent nanospheres could be recognized at a depth of 21 mm into tissue-like media. Small animal imaging with a 1 mm diameter cylindrical target demonstrated that fast 3D data acquisition can be achieved by this multi-pinhole collimator approach to image high-resolution luminescence through a whole animal.
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12
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Pogue BW, Wilson BC. Optical and x-ray technology synergies enabling diagnostic and therapeutic applications in medicine. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-17. [PMID: 30350489 PMCID: PMC6197862 DOI: 10.1117/1.jbo.23.12.121610] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/24/2018] [Indexed: 05/10/2023]
Abstract
X-ray and optical technologies are the two central pillars for human imaging and therapy. The strengths of x-rays are deep tissue penetration, effective cytotoxicity, and the ability to image with robust projection and computed-tomography methods. The major limitations of x-ray use are the lack of molecular specificity and the carcinogenic risk. In comparison, optical interactions with tissue are strongly scatter dominated, leading to limited tissue penetration, making imaging and therapy largely restricted to superficial or endoscopically directed tissues. However, optical photon energies are comparable with molecular energy levels, thereby providing the strength of intrinsic molecular specificity. Additionally, optical technologies are highly advanced and diversified, being ubiquitously used throughout medicine as the single largest technology sector. Both have dominant spatial localization value, achieved with optical surface scanning or x-ray internal visualization, where one often is used with the other. Therapeutic delivery can also be enhanced by their synergy, where radio-optical and optical-radio interactions can inform about dose or amplify the clinical therapeutic value. An emerging trend is the integration of nanoparticles to serve as molecular intermediates or energy transducers for imaging and therapy, requiring careful design for the interaction either by scintillation or Cherenkov light, and the nanoscale design is impacted by the choices of optical interaction mechanism. The enhancement of optical molecular sensing or sensitization of tissue using x-rays as the energy source is an important emerging field combining x-ray tissue penetration in radiation oncology with the molecular specificity and packaging of optical probes or molecular localization. The ways in which x-rays can enable optical procedures, or optics can enable x-ray procedures, provide a range of new opportunities in both diagnostic and therapeutic medicine. Taken together, these two technologies form the basis for the vast majority of diagnostics and therapeutics in use in clinical medicine.
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Affiliation(s)
- Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Geisel School of Medicine, Hanover, New Hampshire, United States
| | - Brian C. Wilson
- University of Toronto, Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario, Canada
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13
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Jia MJ, Bruza P, Jarvis LA, Gladstone DJ, Pogue BW. Multi-beam scan analysis with a clinical LINAC for high resolution Cherenkov-excited molecular luminescence imaging in tissue. BIOMEDICAL OPTICS EXPRESS 2018; 9:4217-4234. [PMID: 30615721 PMCID: PMC6157777 DOI: 10.1364/boe.9.004217] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/16/2018] [Accepted: 08/06/2018] [Indexed: 05/22/2023]
Abstract
Cherenkov-excited luminescence scanned imaging (CELSI) is achieved with external beam radiotherapy to map out molecular luminescence intensity or lifetime in tissue. Just as in fluorescence microscopy, the choice of excitation geometry can affect the imaging time, spatial resolution and contrast recovered. In this study, the use of spatially patterned illumination was systematically studied comparing scan shapes, starting with line scan and block patterns and increasing from single beams to multiple parallel beams and then to clinically used treatment plans for radiation therapy. The image recovery was improved by a spatial-temporal modulation-demodulation method, which used the ability to capture simultaneous images of the excitation Cherenkov beam shape to deconvolve the CELSI images. Experimental studies used the multi-leaf collimator on a clinical linear accelerator (LINAC) to create the scanning patterns, and image resolution and contrast recovery were tested at different depths of tissue phantom material. As hypothesized, the smallest illumination squares achieved optimal resolution, but at the cost of lower signal and slower imaging time. Having larger excitation blocks provided superior signal but at the cost of increased radiation dose and lower resolution. Increasing the scan beams to multiple block patterns improved the performance in terms of image fidelity, lower radiation dose and faster acquisition. The spatial resolution was mostly dependent upon pixel area with an optimized side length near 38mm and a beam scan pitch of P = 0.33, and the achievable imaging depth was increased from 14mm to 18mm with sufficient resolving power for 1mm sized test objects. As a proof-of-concept, in-vivo tumor mouse imaging was performed to show 3D rendering and quantification of tissue pO2 with values of 5.6mmHg in a tumor and 77mmHg in normal tissue.
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Affiliation(s)
- Mengyu Jeremy Jia
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
| | - Lesley A. Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
- Norris Cotton Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
- Norris Cotton Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
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14
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Pogue BW, Feng J, LaRochelle EP, Bruža P, Lin H, Zhang R, Shell JR, Dehghani H, Davis SC, Vinogradov SA, Gladstone DJ, Jarvis LA. Maps of in vivo oxygen pressure with submillimetre resolution and nanomolar sensitivity enabled by Cherenkov-excited luminescence scanned imaging. Nat Biomed Eng 2018; 2:254-264. [PMID: 30899599 PMCID: PMC6424530 DOI: 10.1038/s41551-018-0220-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Low signal-to-noise ratios and limited imaging depths restrict the ability of optical-imaging modalities to detect and accurately quantify molecular emissions from tissue. Here, by using a scanning external X-ray beam from a clinical linear accelerator to induce Cherenkov excitation of luminescence in tissue, we demonstrate in vivo mapping of the oxygenation of tumours at depths of several millimetres, with submillimetre resolution and nanomolar sensitivity. This was achieved by scanning thin sheets of the X-ray beam orthogonally to the emission-detection plane, and by detecting the signal via a time-gated CCD camera synchronized to the radiation pulse. We also show with experiments using phantoms and with simulations that the performance of Cherenkov-excited luminescence scanned imaging (CELSI) is limited by beam size, scan geometry, probe concentration, radiation dose and tissue depth. CELSI might provide the highest sensitivity and resolution in the optical imaging of molecular tracers in vivo.
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Affiliation(s)
- Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA. .,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
| | - Jinchao Feng
- Faculty of Information Technology, Beijing University of Technology, Beijing, China
| | | | - Petr Bruža
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Huiyun Lin
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Jennifer R Shell
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Hamid Dehghani
- School of Computer Science, University of Birmingham, Birmingham, UK
| | - Scott C Davis
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.,Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Lesley A Jarvis
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
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15
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Ahmed SR, Jia JM, Bruza P, Vinogradov S, Jiang S, Gladstone DJ, Jarvis LA, Pogue BW. Radiotherapy-induced Cherenkov luminescence imaging in a human body phantom. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-4. [PMID: 29560623 PMCID: PMC7560997 DOI: 10.1117/1.jbo.23.3.030504] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/26/2018] [Indexed: 05/25/2023]
Abstract
Radiation therapy produces Cherenkov optical emission in tissue, and this light can be utilized to activate molecular probes. The feasibility of sensing luminescence from a tissue molecular oxygen sensor from within a human body phantom was examined using the geometry of the axillary lymph node region. Detection of regions down to 30-mm deep was feasible with submillimeter spatial resolution with the total quantity of the phosphorescent sensor PtG4 near 1 nanomole. Radiation sheet scanning in an epi-illumination geometry provided optimal coverage, and maximum intensity projection images provided illustration of the concept. This work provides the preliminary information needed to attempt this type of imaging in vivo.
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Affiliation(s)
- Syed Rakin Ahmed
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Jeremy Mengyu Jia
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - Sergei Vinogradov
- University of Pennsylvania, Departments of Biophysics and Biochemistry and of Chemistry, Philadelphia, Pennsylvania, United States
| | - Shudong Jiang
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
| | - David J. Gladstone
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Geisel School of Medicine at Dartmouth, Department of Medicine, Hanover, New Hampshire, United States
- Dartmouth–Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
| | - Lesley A. Jarvis
- Geisel School of Medicine at Dartmouth, Department of Medicine, Hanover, New Hampshire, United States
- Dartmouth–Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States
- Dartmouth–Hitchcock Medical Center, Norris Cotton Cancer Center, Lebanon, New Hampshire, United States
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16
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Dsouza A, Lin H, Gunn JR, Gladstone DJ, Jarvis LA, Pogue BW. Cherenkov-excited Multi-Fluorophore Sensing in Tissue-Simulating Phantoms and In Vivo from External Beam Radiotherapy. Radiat Res 2017; 189:197-204. [PMID: 29251551 DOI: 10.1667/rr14943.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In this work, Cherenkov-excited molecular sensing was used to assess the potential for simultaneous quantitative sensing of two NIR fluorophores within tissue-simulating phantoms through spectral separation of signals. Cherenkov emissions induced by external beam gamma photon radiation treatment to tissues/tissue-simulating phantoms were detectable over the 500-900-nm wavelength range. The presence of blood was demonstrated to reduce the integrated intensity of detected Cherenkov emissions by nearly 50%, predominantly at wavelengths below 620 nm. The molecular dyes, IRDye 680RD and IRDye 800CW, have excitation and emission spectra at longer wavelengths than the strongest blood absorption peaks, and also where the intensity of Cherenkov light is at its lowest, so that the emission signal relative to background signal is maximized. Tissue phantoms composed of 1% intralipid and 1% blood were used to simulate human breast tissue, and vials containing fluorophore were embedded in the media, and irradiated with gamma photons for Cherenkov excitation. We observed that fluorescence emissions excited by the Cherenkov signal produced within the phantom could be detected at 5-mm depth into the media within a 0.1-25 μ M fluorophore concentration range. The detected fluorescence signals from these dyes showed linear relationships with radiation doses down to the cGy level. In vivo tests were successful only within the range near a μ M, suggesting that these could be used for metabolic probes in vivo where the local concentrations are near this range.
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Affiliation(s)
| | - Huiyun Lin
- a Thayer School of Engineering and.,d Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, 350007, P.R. China
| | | | - David J Gladstone
- a Thayer School of Engineering and.,b Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755.,c Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756; and
| | - Lesley A Jarvis
- b Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755.,c Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756; and
| | - Brian W Pogue
- a Thayer School of Engineering and.,c Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756; and
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17
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Quigley BP, Smith CD, Cheng SH, Souris JS, Pelizzari CA, Chen CT, Lo LW, Reft CS, Wiersma RD, La Riviere PJ. Sensitivity evaluation and selective plane imaging geometry for x-ray-induced luminescence imaging. Med Phys 2017; 44:5367-5377. [PMID: 28703922 DOI: 10.1002/mp.12470] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/26/2017] [Accepted: 07/06/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE X-ray-induced luminescence (XIL) is a hybrid x-ray/optical imaging modality that employs nanophosphors that luminescence in response to x-ray irradiation. X-ray-activated phosphorescent nanoparticles have potential applications in radiation therapy as theranostics, nanodosimeters, or radiosensitizers. Extracting clinically relevant information from the luminescent signal requires the development of a robust imaging model that can determine nanophosphor distributions at depth in an optically scattering environment from surface radiance measurements. The applications of XIL in radiotherapy will be limited by the dose-dependent sensitivity at depth in tissue. We propose a novel geometry called selective plane XIL (SPXIL), and apply it to experimental measurements in optical gel phantoms and sensitivity simulations. METHODS An imaging model is presented based on the selective plane geometry which can determine the detected diffuse optical signal for a given x-ray dose and nanophosphor distribution at depth in a semi-infinite, optically homogenous material. The surface radiance in the model is calculated using an analytical solution to the extrapolated boundary condition. Y2 O3 :Eu3+ nanoparticles are synthesized and inserted into various optical phantom in order to measure the luminescent output per unit dose for a given concentration of nanophosphors and calibrate an imaging model for XIL sensitivity simulations. SPXIL imaging with a dual-source optical gel phantom is performed, and an iterative Richardson-Lucy deconvolution using a shifted Poisson noise model is applied to the measurements in order to reconstruct the nanophosphor distribution. RESULTS Nanophosphor characterizations showed a peak emission at 611 nm, a linear luminescent response to tube current and nanoparticle concentration, and a quadratic luminescent response to tube voltage. The luminescent efficiency calculation accomplished with calibrated bioluminescence mouse phantoms determines 1.06 photons were emitted per keV of x-ray radiation absorbed per g/mL of nanophosphor concentration. Sensitivity simulations determined that XIL could detect a concentration of 1 mg/mL of nanophosphors with a dose of 1 cGy at a depth ranging from 2 to 4 cm, depending on the optical parameters of the homogeneous diffuse optical environment. The deconvolution applied to the SPXIL measurements could resolve two sources 1 cm apart up to a depth of 1.75 cm in the diffuse phantom. CONCLUSIONS We present a novel imaging geometry for XIL in a homogenous, diffuse optical environment. Basic characterization of Y2 O3 :Eu3+ nanophosphors are presented along with XIL/SPXIL measurements in optical gel phantoms. The diffuse optical imaging model is validated using these measurements and then calibrated in order to execute initial sensitivity simulations for the dose-depth limitations of XIL imaging. The SPXIL imaging model is used to perform a deconvolution on a dual-source phantom, which successfully reconstructs the nanophosphor distributions.
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Affiliation(s)
- Bryan P Quigley
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Corey D Smith
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Shih-Hsun Cheng
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Jeffrey S Souris
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Charles A Pelizzari
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL, 60637, USA
| | - Chin-Tu Chen
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Leu-Wei Lo
- Department of Radiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Chester S Reft
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL, 60637, USA
| | - Rodney D Wiersma
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL, 60637, USA
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18
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Darafsheh A, Taleei R, Kassaee A, Finlay JC. Proton therapy dosimetry using the scintillation of the silica fibers. OPTICS LETTERS 2017; 42:847-850. [PMID: 28198880 DOI: 10.1364/ol.42.000847] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the feasibility of proton therapy dose measurement by using scintillation of a bare silica glass fiber. The emission spectra of the optical fiber at various depths in tissue-mimicking phantoms, irradiated with proton beams of energies 100-225 MeV show two distinct peaks at 460 and 650 nm whose nature is connected with the silica point defects. Our experimental results and Monte Carlo simulation showed that the Čerenkov radiation cannot be responsible for such a phenomenon. We showed that the intensity of the peak at 650 nm correlates with the proton dose with a minimal effect of ionization quenching, while the intensity peak at 460 nm under-reports the radiation dose.
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