Bioluminescence tomography using eigenvectors expansion and iterative solution for the optimized permissible source region

Naser, Mohamed A.; Patterson, Michael S.

doi:10.1364/boe.2.003179

Cited by 25 publications

(21 citation statements)

References 30 publications

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“…The BLT results shown in Figures 10 and 11 are obtained using our BLT algorithm which is based on eigenvector decomposition and adaptive shrinking of the permissible source region (Naser et al 2012 and Naser and Patterson 2011). The spectrally resolved data at 5 wavelengths were used along with optimized selection of the permissible source region.…”

Section: Resultsmentioning

confidence: 99%

Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

2014

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A reconstruction algorithm for diffuse optical tomography (DOT) based on diffusion theory and finite element method is described. The algorithm reconstructs the optical properties in a permissible domain or region of interest to reduce the number of unknowns. The algorithm can be used to reconstruct optical properties for a segmented object (where a CT-scan or MRI is available) or a non-segmented object. For the latter, an adaptive segmentation algorithm merges contiguous regions with similar optical properties thereby reducing the number of unknowns. In calculating the Jacobian matrix the algorithm uses an efficient direct method so the required time is comparable to that needed for a single forward calculation. The reconstructed optical properties using segmented, non-segmented, and adaptively segmented 3D mouse anatomy (MOBY) are used to perform bioluminescence tomography (BLT) for two simulated internal sources. The BLT results suggest that the accuracy of reconstruction of total source power obtained without the segmentation provided by an auxiliary imaging method such as x-ray CT is comparable to that obtained when using perfect segmentation.

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Section: Resultsmentioning

confidence: 99%

Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

2014

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“…In this study, we introduce an online BLT-SARRP system to demonstrate BLT-guided radiation for the first time. Compared with the earlier work from Yang et al (28), this paper integrates multispectral BLT (25, 29), the IVTCG method (30) and permissible source region (31) developed by our group and collaborators to enable fast and accurate CoM reconstruction. Furthermore, the new algorithm enables better conformality of the reconstructed source distributions without a predefined region of interest (see Figure 2 vs.…”

Section: Discussionmentioning

confidence: 99%

“…To improve convergence and reduce the computation time, an iterative strategy was chosen to adaptively shrink the solution space (31). The initial permissible solution space is the whole mesh domain except the surface nodes.…”

Section: Methodsmentioning

confidence: 99%

“…Because of the online design, we were able to demonstrate BLT-guided radiation therapy on the SARRP for the first time. Multispectral BLT (29), inverse calculation using the incomplete variables truncated conjugate gradient (IVTCG) method (30) and a permissible region shrinking strategy (31) were combined to enable fast and accurate BLT reconstruction. Studies were performed in a phantom and mouse carcasses with an implanted light source to show the capability of BLT-guided radiation therapy.…”

Section: Introductionmentioning

confidence: 99%

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Bioluminescence Tomography–Guided Radiation Therapy for Preclinical Research

Zhang

Wang

et al. 2016

International Journal of Radiation Oncology*Biology*Physics

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Purpose In pre-clinical radiation research, it is challenging to localize soft tissue targets based on cone beam computed tomography (CBCT)-guidance. As a more effective method to localize soft tissue targets, we developed an online bioluminescence tomography (BLT) system for the small animal radiation research platform (SARRP). We demonstrated BLT-guided radiotherapy and validated targeting accuracy, based on a newly developed reconstruction algorithm. Methods and Materials The BLT system was designed to dock onto the SARRP for image acquisition and to be detached before radiation delivery. A 3-mirror system was devised to reflect the bioluminescence emitted from the subject to a stationary CCD camera. Multispectral BLT and the incomplete variables truncated conjugate gradient method with a permissible region shrinking strategy were employed as the optimization scheme to reconstruct bioluminescent source distributions. To validate BLT targeting accuracy, a small cylindrical light source with high CBCT contrast was placed in a phantom and also in the abdomen of a mouse carcass. The center of mass (CoM) of the source was recovered from BLT and used to guide radiation delivery. The accuracy of the BLT-guided targeting was validated with films and compared with the CBCT-guided delivery. In vivo experiments were conducted to demonstrate the BLT localization capability for various source geometries. Results Online BLT was able to recover the CoM of the imbedded light source with an average accuracy of 1 mm compared to CBCT localization. The difference between the BLT- and CBCT-guided irradiation shown on the films was consistent with the source localization revealed in the BLT and CBCT images. The in vivo results demonstrated that our BLT system could potentially be applied for multiple targets and tumors. Conclusions The online BLT/CBCT/SARRP system provides an effective solution for soft tissue targeting, particularly for small, non-palpable, or orthotopic tumor models.

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“…The detail of the reconstruction algorithm has been previously reported elsewhere (19). Briefly, the light propagation in tissue is described by the diffusion equation and the incomplete variables truncated conjugate gradient (IVTCG) algorithm with adaptive shrinking strategy (19, 24, 25) was chosen as the reconstruction scheme. The optical properties, as described in our previously published work, were selected to describe the light absorption and scattering in the abdomen region (19).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of On- and Off-Line Bioluminescence Tomography System for Focal Irradiation Guidance

et al. 2016

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In response to the limitations of computed tomography (CT) and cone-beam CT (CBCT) in irradiation guidance, especially for soft-tissue targets without the use of contrast agents, our group developed a solution that implemented bioluminescence tomography (BLT) as the image-guidance modality for preclinical radiation research. However, adding such a system to existing small animal irradiators is no small task. A potential solution is to utilize an off-line BLT system in close proximity to the irradiator, with stable and effective animal transport between the two systems. In this study, we investigated the localization accuracy of an off-line BLT system when used for the small animal radiation research platform (SARRP) and compared the results with those of an on-line system. The CBCT was equipped on both the off-line BLT system and the SARRP, with a distance of 5 m between them. To evaluate the setup error during animal transport between the two systems, the mice underwent CBCT imaging on the SARRP and were then transported to the off-line system for a second CBCT imaging session. The normalized intensity difference of the two images and the corresponding histogram and correlation were computed to evaluate if the transport process perturbed animal positioning. Strong correlation (correlation coefficients >0.95) between the SARRP and the off-line mouse CBCT was observed. The offset of the implanted light source center can be maintained within 0.2 mm during transport. To compare the target localization accuracy using the on-line SARRP BLT and the off-line system, a self-illuminated bioluminescent source was implanted in the abdomen of anesthetized mice. In addition to the application for dose calculation, CBCT imaging was also employed to generate the mesh grid of the imaged mouse for BLT reconstruction. Two scenarios were devised and compared, which involved localization of the luminescence source based on either: 1. on-line SARRP bioluminescence image and CBCT; or 2. off-line bioluminescence image and SARRP CBCT. The first scenario is assumed to have the least setup error, because no animal transport was involved. The second scenario examines if an off-line BLT system, with the mesh generated from the SARRP CBCT, can be used to guide SARRP irradiation when there is minimal target contrast in CBCT. Stability during animal transport between the two systems was maintained. The center of mass (CoM) of the light source reconstructed by the off-line BLT had an offset of 1.0 ± 0.4 mm from the true CoM derived from the SARRP CBCT. These results are comparable to the offset of 1.0 ± 0.2 mm using on-line BLT. With CBCT information provided by the SARRP and effective animal immobilization during transport, these findings support the utilization of an off-line BLT-guided system, in close proximity to the SARRP, for accurate soft-tissue target localization. In addition, a dedicated standalone BLT system for our partner site at the University of Pennsylvania was introduced in this study.

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Bioluminescence tomography using eigenvectors expansion and iterative solution for the optimized permissible source region

Cited by 25 publications

References 30 publications

Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

Algorithm for localized adaptive diffuse optical tomography and its application in bioluminescence tomography

Bioluminescence Tomography–Guided Radiation Therapy for Preclinical Research

Evaluation of On- and Off-Line Bioluminescence Tomography System for Focal Irradiation Guidance

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