CT and MRI fusion for postimplant prostate brachytherapy evaluation

Dehghan, Ehsan; Le, Yi; Lee, Junghoon; Song, Daniel Y.; Fichtinger, Gabor; Prince, Jerry L.

doi:10.1109/isbi.2016.7493345

Cited by 4 publications

(10 citation statements)

References 11 publications

(13 reference statements)

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“…Clinical workflows employing CT-MRI fusion taking advantage of both imaging modalities are currently implemented at many centers, however, this requires additional resources and patient transfers. Furthermore, the inherent uncertainties associated with CT-MRI image registration can be significant (Dehghan et al, 2016;Kunogi et al, 2015;Polo et al, 2004b). An MRI-only workflow for post-implant dosimetry of LDR brachytherapy seeds thus would be an ideal solution.…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…However, in practice, the unavoidable uncertainties associated with the image registration/fusion process lead to nonnegligible dosimetric errors (Tanaka et al, 2006a). It has been shown that the uncertainties associated with the MR-CT fusion may lead to up to 16% deviation in D90(De Brabandere, Dehghan et al, 2016;Kunogi et al, 2015;Polo et al, 2004b). Various techniques for improving CT-MRI fusion have been proposed (Kunogi et al, 2015;Polo et al, 2004b), but the inherent flaws associated with the process (e.g., patient positioning during image acquisition and organ deformations during transfer) limits these techniques.…”

Section: Low Dose Rate Brachytherapymentioning

confidence: 99%

“…Thus, CT and MRI are complementary modalities to provide both clear seed identification as well as high contrast anatomical visualization of the prostate. Clinical workflows employing CT-MRI registration taking advantage of both imaging modalities is currently implemented at many centers, however this involves additional resources, patient transfers and image registration error (Dehghan et al, 2016;Kunogi et al, 2015;Polo et al, 2004b). An MRI-only workflow for post-implant dosimetry of LDR brachytherapy seeds thus would be an ideal solution for many clinics.…”

Section: Introductionmentioning

confidence: 99%

“…The CT-MRI fusion workflow has been recommended by the recent American Brachytherapy Society (ABS) guideline to take advantage of both imaging modalities by CT-based seed localization with MRI-based target delineation (Davis et al, 2012). It has been shown that the uncertainties associated with the MR-CT fusion may lead to up to 16% deviation in dose to 90% of the prostate (D90) Dehghan et al, 2016;Kunogi et al, 2015;Polo et al, 2004b).…”

Section: Introductionmentioning

confidence: 99%

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Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

Nosrati¹

2021

Preprint

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Permanent implantation of low-dose-rate (LDR) brachytherapy seeds is a well-established treatment modality for patients with localized prostate cancer. The quality of the implant is assessed within 30 days following implantation through post-implant dosimetry. The standard recommended procedure for post-implant dosimetry is based on computed tomography (CT). CT provides excellent seed visualization and localization; however, due to poor soft tissue contrast and challenging anatomical identificatio,n it leads to significant interobserver variabilities. The current MRI-CT fusion-based workflow for post-implant dosimetry LDR prostate brachytherapy takes advantage of the superior soft tissue contrast of MRI but still relies on CT for seed visualization and detection, and it suffers from image fusion uncertainties and extra cost and logistics. The lack of positive contrast from brachytherapy seeds in conventional MR images remains a major challenge towards an MRI-only workflow for post-implant dosimetry of Low- Dose-Rate (LDR) brachytherapy. In this thesis, a clinically feasible MRI-based workflow has been developed for brachytherapy seed visualization and localization. The seed visualization is based on a novel Quantitative Susceptibility Mapping (QSM) algorithm. The proposed seed localization on QSM utilizes machine learning algorithms. The reliability of the proposed workflow has been validated on 23 patients by comparing the seed positions and final dosimetric parameters between the proposed MRI-only workflow and the clinical CT-MRI fusion-based approach and there was excellent agreement between the two methods.

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Section: Acknowledgmentsmentioning

confidence: 99%

Section: Low Dose Rate Brachytherapymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

Nosrati¹

2021

Preprint

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“…In contrast, Magnetic Resonance Imaging (MRI) provide the better contrast for differentiating soft tissue. However, seed and catheter localization in MRI images is challenging [ 8 , 9 ]. Besides, its relative sensitivity to movement in MRI.…”

Section: Introductionmentioning

confidence: 99%

Value of CT-MRI fusion in iodine-125 brachytherapy for high-grade glioma

et al. 2017

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PurposesTo develop a fast, accurate and robust method of fusing Computed Tomography (CT) with pre-operative Magnetic Resonance Imaging (MRI) and evaluate the impact of using the fused data on the implantation of Iodine-125 (125I) seeds for brachytherapy of high-grade gliomas (HGG).MethodsA study was performed on a cohort of 10 consecutive patients with HGG were treated by 125I brachytherapy with CT-MRI fusion image guided (CMGB), and 10 patients treated with CT alone guided (CGB). Statistical analysis was performed to compare (1) the planning target volume, (2) the accuracy of location of catheters, (3) the target volume covered by 150% prescribe dose (V150), (4) the target volume covered by 200% prescribe dose (V200), and (5) the conformity index (CI) with or without fused data.ResultsThe median planning target volume was 50.1 cm3 in CGB, and 56.25 cm3 in CMGB with significant difference (p = 0.005). The accuracy of catheter insertion was 94.4% with CMGB and 78.9% with CGB. The median V150 and V200 was 45.32% vs 64.24% and 32.81% vs 53.17% in CGB and CMGB, respectively. There was significant difference for CI (83.5% vs. 74.5%, p < 0.05) in the two groups for the post-operative verification.ConclusionsThe proposed MRI-CT fusion method enables a quantitative assessment of impact on HGG brachytherapy. The additional information obtained from the fused images can be utilized for more accurate delineation of lesion boundaries and targeting of catheters. Experimental results show that the fusion algorithm is robust and reliable in clinical practice.

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Potential applications of the quantitative susceptibility mapping (QSM) in MR-guided radiation therapy

Nosrati¹,

Paudel²,

Ravi³

et al. 2019

Phys. Med. Biol.

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Magnetic resonance-guided radiation therapy (MR-GRT) offers great potential to improve radiation treatment outcomes by providing more accurate and patient-tailored therapy. Despite superior soft tissue contrast in MRI, one of the challenges towards MRI-only workflows is that the process often requires some sort of ‘MR-invisible’ metal-based devices. In this study, the feasibility of quantitative susceptibility mapping (QSM) for visualization of some MR-invisible radiation therapy devices was studied. Our recently proposed QSM-based algorithm for brachytherapy seed visualization was modified and the feasibility of the optimized algorithm for visualization of different devices including: brachytherapy seeds, plastic interstitial needles, CT-markers and obturators, and different types of fiducial markers in agar, prostate and meat phantoms were studied. All phantoms were scanned using 3T MR scanner with a 3D multi-echo gradient recalled echo (ME-GRE) pulse sequence. The QSM results in all phantoms were compared to CT images for spatial accuracy of the QSM. The applied post-processing algorithm was found to be insensitive to the seeds’ type; also, presence of nearby calcifications had no effect on seed visualization. QSM successfully generated positive contrast for both types of investigated fiducial markers with high spatial accuracy compared to CT. Interstitial needles containing both aluminum-based CT-maker and titanium-based obturators were accurately depicted on the QSM. The proposed QSM-based technique relies on the standard MR pulse sequences and visualize the conventional MR-invisible metallic devices with CT-like positive contrast solely through post-processing. Upon in vivo validation of the technique, QSM may have the potential to replace CT for an MR-only guided radiation therapy.

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CT and MRI fusion for postimplant prostate brachytherapy evaluation

Cited by 4 publications

References 11 publications

Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

Development of an MRI-Based Workflow for Post-implant Dosimetry of Prostate Low-Dose-Rate (Ldr) Brachytherapy

Value of CT-MRI fusion in iodine-125 brachytherapy for high-grade glioma

Potential applications of the quantitative susceptibility mapping (QSM) in MR-guided radiation therapy

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