Technical Note: Adapting a <scp>GE SIGNA PET</scp>/<scp>MR</scp> scanner for radiotherapy

Brynolfsson, Patrik; Axelsson, Jan; Holmberg, August; Jönsson, Johan; Goldhaber, David M.; Jian, Yiqiang; Illerstam, Fredrik; Engström, Mats; Zackrisson, Björn; Nyholm, Tufve

doi:10.1002/mp.13032

Cited by 11 publications

(16 citation statements)

References 22 publications

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“…The increased separation between the coil and the phantom led to a 32.4% drop in SNR. This was within the SNR reductions of 44% [23] , 42% [10] , 33% [9] and 14% [33] reported in literature for similar MRI in RT image acquisitions.…”

Section: Discussionsupporting

confidence: 89%

“…RT-specific demands like patient positioning (flat tabletop-inserts) and immobilization devices needed to replicate patient treatment position also affect MR image quality. For example, by using a flat tabletop-insert and coil holder, Brynolfsson et al [9] reported that SNR reduced to 66% whilst Xing et al [10] , had an average SNR decrease of 42%. Batumalai et al [11] , showed that for supine RT-specific imaging of the breast, a switch from the standard diagnostic 16-channel prone coil to an 18-channel surface coil decreased SNR by 41% and 45% for supine flat and supine inclined (10°) respectively.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity analysis of different quality assurance methods for magnetic resonance imaging in radiotherapy

Adjeiwaah

Garpebring

Nyholm

2020

Physics and Imaging in Radiation Oncology

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Background and purpose: There are currently no standard quality assurance (QA) methods for magnetic resonance imaging (MRI) in radiotherapy (RT). This work was aimed at evaluating the ability of two QA protocols to detect common events that affect quality of MR images under RT settings. Materials and methods: The American College of Radiology (ACR) MRI QA phantom was repeatedly scanned using a flexible coil and action limits for key image quality parameters were derived. Using an exploratory survey, issues that reduce MR image quality were identified. The most commonly occurring events were introduced as provocations to produce MR images with degraded quality. From these images, detection sensitivities of the ACR MRI QA protocol and a commercial geometric accuracy phantom were determined. Results: Machine-specific action limits for key image quality parameters set at ± mean 3 were comparable with the ACR acceptable values. For the geometric accuracy phantom, provocations from uncorrected gradient nonlinearity effects and a piece of metal in the bore of the scanner resulted in worst distortions of 22.2 mm and 3.4 mm, respectively. The ACR phantom was sensitive to uncorrected signal variations, electric interference and a piece of metal in the bore of the scanner but could not adequately detect individual coil element failures. Conclusions: The ACR MRI QA phantom combined with the large field-of-view commercial geometric accuracy phantom were generally sensitive in identifying some common MR image quality issues. The two protocols when combined may provide a tool to monitor the performance of MRI systems in the radiotherapy environment.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Sensitivity analysis of different quality assurance methods for magnetic resonance imaging in radiotherapy

Adjeiwaah

Garpebring

Nyholm

2020

Physics and Imaging in Radiation Oncology

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“…A few solutions have been proposed for adapting PET/ MRI scanners to meet RT requirements. 29,30 For patients with HNC, Paulus et al 13 proposed an alternative patient setup and coil arrangement that, unlike standard head and neck coil usage, allows proper patient positioning with fixation masks. Winter et al 31 further studied the feasibility and image quality of this setup and concluded that the requirements for RT treatment planning were met.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Multiparametric Positron Emission Tomography/Magnetic Resonance Imaging as a One-Stop Shop for Radiation Therapy Planning for Patients with Head and Neck Cancer

Olin

Hansen

Rasmussen

et al. 2020

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Multiparametric positron emission tomography (PET)/magnetic resonance imaging (MRI) as a one-stop shop for radiation therapy (RT) planning has great potential but is technically challenging. We studied the feasibility of performing multiparametric PET/MRI of patients with head and neck cancer (HNC) in RT treatment position. As a step toward planning RT based solely on PET/MRI, a deep learning approach was employed to generate synthetic computed tomography (sCT) from MRI. This was subsequently evaluated for dose calculation and PET attenuation correction (AC). Methods and Materials: Eleven patients, including 3 pilot patients referred for RT of HNC, underwent PET/MRI in treatment position after a routine fluorodeoxyglucose-PET/CT planning scan. The PET/MRI scan protocol included multiparametric imaging. A convolutional neural network was trained in a leave-one-out process to predict sCT from the Dixon MRI. The clinical CT-based dose plans were recalculated on sCT, and the plans were compared in terms of relative differences in mean,

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“…On the other hand, the MRI cannot be used for intra-fraction monitoring, and additional time is required to move the MRI scanner in and out of the room. A similar approach using a 1.5 T scanner was developed in Umea in which the patient rather than the MRI scanner is moved (Karlsson et al 2009), although this system has recently been decommissioned and replaced with a PET/MRI scanner (Brynolfsson et al 2018). Table II shows a comparison of existing in-room/near-room MRI systems.…”

Section: In-room Mri Radiotherapy Systemsmentioning

confidence: 99%

MRI-guidance for motion management in external beam radiotherapy: current status and future challenges

et al. 2018

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Technical Note: Adapting a GE SIGNA PET/MR scanner for radiotherapy

Cited by 11 publications

References 22 publications

Sensitivity analysis of different quality assurance methods for magnetic resonance imaging in radiotherapy

Sensitivity analysis of different quality assurance methods for magnetic resonance imaging in radiotherapy

Feasibility of Multiparametric Positron Emission Tomography/Magnetic Resonance Imaging as a One-Stop Shop for Radiation Therapy Planning for Patients with Head and Neck Cancer

MRI-guidance for motion management in external beam radiotherapy: current status and future challenges

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