Comparison of computed tomography and magnetic resonance based target volume in brain tumors

Prabhakar, R; Haresh, K.P.; Ganesh, T; Joshi, Rajesh; Julka, P.K.; Rath, GK

doi:10.4103/0973-1482.34694

Cited by 45 publications

(36 citation statements)

References 4 publications

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“…Because of its characteristics, this method should be more sensitive to targeting incongruence than center of mass or related methods (26)(27)(28).…”

Section: Discussionmentioning

confidence: 98%

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

MacFadden

Zhang

Brock

et al. 2010

International Journal of Radiation Oncology*Biology*Physics

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“…Because of its characteristics, this method should be more sensitive to targeting incongruence than center of mass or related methods (26)(27)(28).…”

Section: Discussionmentioning

confidence: 98%

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

MacFadden

Zhang

Brock

et al. 2010

International Journal of Radiation Oncology*Biology*Physics

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“…The main reason is the superior soft tissue contrast which improves target and organ at risk (OAR) definition in the brain and other sites as compared to CT-based delineations. [1][2][3] In order to transfer the MRI delineations to the CT, the two scans must be aligned. This is usually done by a manual and/or automatic rigid registration between the CT and MRI scan.…”

Section: Introductionmentioning

confidence: 99%

Patch‐based generation of a pseudo CT from conventional MRI sequences for MRI‐only radiotherapy of the brain

et al. 2015

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Purpose: In radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, the information on electron density must be derived from the MRI scan by creating a so-called pseudo computed tomography (pCT). This is a nontrivial task, since the voxel-intensities in an MRI scan are not uniquely related to electron density. To solve the task, voxel-based or atlas-based models have typically been used. The voxel-based models require a specialized dual ultrashort echo time MRI sequence for bone visualization and the atlas-based models require deformable registrations of conventional MRI scans. In this study, we investigate the potential of a patch-based method for creating a pCT based on conventional T 1 -weighted MRI scans without using deformable registrations. We compare this method against two state-of-the-art methods within the voxel-based and atlas-based categories. Methods: The data consisted of CT and MRI scans of five cranial RT patients. To compare the performance of the different methods, a nested cross validation was done to find optimal model parameters for all the methods. Voxel-wise and geometric evaluations of the pCTs were done. Furthermore, a radiologic evaluation based on water equivalent path lengths was carried out, comparing the upper hemisphere of the head in the pCT and the real CT. Finally, the dosimetric accuracy was tested and compared for a photon treatment plan. Results: The pCTs produced with the patch-based method had the best voxel-wise, geometric, and radiologic agreement with the real CT, closely followed by the atlas-based method. In terms of the dosimetric accuracy, the patch-based method had average deviations of less than 0.5% in measures related to target coverage. Conclusions: We showed that a patch-based method could generate an accurate pCT based on conventional T 1 -weighted MRI sequences and without deformable registrations. In our evaluations, the method performed better than existing voxel-based and atlas-based methods and showed a promising potential for RT of the brain based only on MRI. C 2015 American Association of Physicists in Medicine. [http://dx

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“…MRI has reduced interference from metal implants such as prosthetic hips [2] and gold seed implants and therefore has the potential to provide improved target volume delineation over CT. Changes in anatomical and tumour definition as a result of using MRI data compared with CT have been reported for prostate [2][3][4][5][6][7], head and neck [8][9][10][11] and brain cancer [12,13] patients.…”

mentioning

confidence: 99%

The influence of MRI scan position on image registration accuracy, target delineation and calculated dose in prostatic radiotherapy

Hanvey¹,

Sadozye²,

McJury³

et al. 2012

BJR

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Objective: To investigate the necessity of performing MRI in the radiotherapy position when using MRI for prostatic radiotherapy. Methods: 20 prostate patients received a CT, diagnostic MRI and an MRI scan in the radiotherapy position. The quality of registration between CT and MRI was compared between the two MRI set-ups. The prostate and seminal vesicles were contoured using all scans and intensity modulated radiotherapy (IMRT) plans were generated. Changes in the target volume and IMRT plans were investigated. Two-tailed paired Student's ttests determined the statistical significance.Results: There was a decrease in the mean distance from the centre of the bony anatomy between CT and MRI (from 3.9 to 1.9 mm, p-value,0.0001) when the MRI scan was acquired in the radiotherapy position. Assuming that registering CT with an MRI scan in the radiotherapy position is the gold standard for delineating the prostate and seminal vesicles, using a planning target volume delineated on the CT with a diagnostic MRI scan viewed separately, resulted in a mean conformation number of 0.80 instead of the expected 0.98 (p,0.0001). Conclusion: By registering CT with an MRI scan in the radiotherapy position, there is a statistically significant improvement in the registration and IMRT quality. Advances in knowledge: To achieve an acceptable registration and IMRT quality in prostatic radiotherapy, neither CT with a separate diagnostic MRI nor CT registered to a diagnostic MRI will suffice. Instead, a CT registered with an MRI in the radiotherapy position should be used.

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Comparison of computed tomography and magnetic resonance based target volume in brain tumors

Abstract: The study demonstrates that MR is an indispensable imaging modality in radiotherapy for planning brain tumors.

Cited by 45 publications

References 4 publications

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

Patch‐based generation of a pseudo CT from conventional MRI sequences for MRI‐only radiotherapy of the brain

The influence of MRI scan position on image registration accuracy, target delineation and calculated dose in prostatic radiotherapy

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