A Multi-Institutional Experience of MR-Guided Liver Stereotactic Body Radiation Therapy

Rosenberg, Stephen A.; Henke, Lauren E.; Shaverdian, Narek; Mittauer, K.E.; Wojcieszynski, Andrzej P.; Hullett, Craig R.; Kamrava, Mitchell; Lamb, James; Cao, Minsong; Green, Olga L.; Kashani, Rojano; Paliwal, Bhudatt R.; Bayouth, John E.; Harari, Paul M.; Olsen, Jeffrey R.; Lee, Percy; Parikh, Parag J.; Bassetti, M.

doi:10.1016/j.adro.2018.08.005

Cited by 129 publications

(116 citation statements)

References 41 publications

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“…A number of authors have reported on on-table adaption of treatment plans using MRgRT devices [11,[33][34][35][36][37] and also on assessing which patients benefit most from adaptive MRgRT [35,[38][39][40][41][42][43][44]. In the presented study, no online treatment plan adaptions were performed.…”

Section: Discussionmentioning

confidence: 99%

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

et al. 2020

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Purpose Magnetic resonance-guided radiotherapy (MRgRT) has recently been introduced in our institution. As MRgRT requires high patient compliance compared to conventional techniques and can be associated with prolonged treatment times, feasibility and patient tolerance were prospectively assessed using patient-reported outcome questionnaires (PRO-Q). Materials and methods Forty-three patients were enrolled in a prospective observational study and treated with MRgRT on a low-field hybrid Magnetic Resonance Linear Accelerator system (MR-Linac) between April 2018 and April 2019. For assistance in gated breath-hold delivery using cine-MRI, a video feedback system was installed. PRO-Qs consisted of questions on MR-related complaints and also assessed aspects of active patient participation. Results The most commonly treated anatomic sites were nodal metastases and liver lesions. The mean treatment time was 34 min with a mean beam-on time of 2:17 min. Gated stereotactic body radiotherapy (SBRT) was applied in 47% of all patients. Overall, patients scored MRgRT as positive or at least tolerable in the PRO-Q. Almost two thirds of patients (65%) complained about at least one item of the PRO-Q (score ≥4), mainly concerning coldness, paresthesia, and uncomfortable positioning. All patients reported high levels of satisfaction with their active role using the video feedback system in breath-hold delivery. Conclusion MRgRT was successfully implemented in our clinic and well tolerated by all patients, despite MR-related complaints and complaints about uncomfortable immobilization. Prospective clinical studies are in development for further evaluation of MRgRT and for quantification of the benefit of MR-guided on-table adaptive radiotherapy.

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Section: Discussionmentioning

confidence: 99%

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

et al. 2020

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“…MR-Linac based treatment presents several challenges [14,15,25,26]. The current system is limited to 6X-flattening filter-free photons, which can restrict the treatment of deep-seated and larger lesions that require higher beam energies for deeper penetration to yield clinically acceptable plans.…”

Section: Discussionmentioning

confidence: 99%

Real-time Magnetic Resonance-guided Liver Stereotactic Body Radiation Therapy: An Institutional Report Using a Magnetic Resonance-Linac System

Feldman¹,

Modh²,

Glide-Hurst³

et al. 2019

Cureus

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BackgroundStereotactic body radiation therapy (SBRT) is a proven and effective modality for treatment of hepatic primary and metastatic tumors. However, these lesions are challenging for planning and treatment execution due to natural anatomic changes associated with respiration. Magnetic resonance imaging (MRI) offers superior soft tissue contrast resolution and the ability for real-time image-guided treatment delivery and lesion tracking.ObjectiveTo evaluate the plan quality, treatment delivery, and tumor response of a set of liver SBRT cancer treatments delivered with magnetic resonance (MR)-guided radiotherapy on a MR-linear accelerator (MR-linac).MethodsTreatment data from 29 consecutive patients treated with SBRT were reviewed. All treatments were performed using a step and shoot technique to one or more liver lesions on an MR-linac platform. Patients received 45 to 50 Gy prescribed to at least 95% of the planning target volume (PTV) in five fractions except for two patients who received 27-30 Gy in three fractions. Computed tomography and MRI simulation were performed in the supine position prior to treatment in the free-breathing, end exhalation, and end inhalation breath-hold positions to determine patient tolerability and potential dosimetric advantages of each technique. Immobilization consisted of using anterior and posterior torso MRI receive coils embedded in a medium-sized vacuum cushion. Gating was performed using sagittal cine images acquired at 4 frames/second. Gating boundaries were defined in the three major axes to be 0.3 to 0.5 cm. An overlapping region of interest, defined as the percentage volume allowed outside the boundary for beam-on to occur, was set between 1 and 10%. The contoured target was assigned a 5-mm PTV expansion. Organs at risk constraints adopted by the American Association of Physicists in Medicine Task Group 101 were used during optimization.ResultsTwenty-nine patients, with a total of 34 lesions, successfully completed the prescribed treatment with minimal treatment breaks or delays. Twenty-one patients were treated at end-exhale, and six were treated at end-inhale. Two patients were treated using a free-breathing technique due to poor compliance with breath-hold instructions. The reported mean liver dose was 5.56 Gy (1.39 - 10.43; STD 2.85) and the reported mean liver volume receiving the prescribed threshold dose was 103.1 cm3 (2.9 - 236.6; STD 75.2). Follow-up imaging at one to 12 months post treatment confirmed either stable or decreased size of treated lesions in all but one patient. Toxicities were mild and included nausea/vomiting, abdominal pain and one case of bloody diarrhea. Four patients died due to complications from liver cirrhosis unrelated to radiation effect.ConclusionSBRT treatment using a gated technique on an MR-linac has been successfully demonstrated. Potential benefits of this modality include decreased liver dose leading to decreased toxicities. Further studies to identify the benefits and risks associated with MR-guided SBRT are necessary.

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“…Since metal markers were not implanted in or near the tumour, the three-dimensional position deviation of the tumour cannot be analysed using two-dimensional projections. Therefore, implanted metal markers [25]or MR [3]should be used to obtain more soft tissue information and to further analyse the respiratory motion amplitude changes and baseline drifts. If we want to comprehensively analyse the variation of respiratory motion, we need automatic methods to evaluate the two-dimensional projections during whole treatments.…”

Section: Discussionmentioning

confidence: 99%

“…The target area of the liver is affected by inter-fraction errors (mainly the setup errors) and respiratory motion. Therefore, image guided radiotherapy (IGRT) and respiratory motion management strategies must be adopted to correct these errors and improve the accuracy of radiotherapy [1].The IGRT strategies include cone-beam CT (CBCT), KV plain lm [2], MR [3] and EPID, etc. Respiratory motion management includes expanded margin under free breathing, 4D CT [4], tracking [5], gating, and deep inspiration breath-hold (DIBH) [6].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Amplitude Changes and Baseline Drift of Respiratory Motion during Liver Stereotactic Body Radiation Therapy Based on Intra-Fraction CBCT

Zeng

Wang

Zhou

et al. 2020

Preprint

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Abstract Purpose: To evaluate the amplitude changes and baseline drift of respiratory motion in liver stereotactic body radiation therapy based on intra-fraction cone beam CT (CBCT).Materials and methods: Twenty-four liver SBRT patients underwent a four-dimensional computed tomography (4D CT) scan, inter-fraction cone-beam computed tomography (CBCT), and intra-fraction CBCT to evaluate the amplitude changes and baseline drift of respiratory motion. The amplitude changes were defined as the variations between the amplitude measured in the 4D CT and those measured with fluoroscopy in inter- and intra-fraction CBCT. The baseline drifts were defined as the difference between the liver position errors and the setup errors in inter- and intra-fraction CBCT. Manual registration of the liver contour was performed to obtain liver position errors, and bone registration was performed to obtain setup errors. Meanwhile, the correlation among the liver position errors, the relative diaphragm position, and the amplitude changes was evaluated. Results: The systematic and random errors of the baseline drifts for intra-fraction CBCT in the medial-lateral (ML), superior-inferior (SI), and anterior-posterior (AP) views were 0.99 and 1.6 mm, 2.03 and 2.46 mm, and 1.02 and 2.07 mm, respectively. The corresponding PTV margin was 3.61 mm, 6.8 mm, and 4.00 mm, respectively. The amplitude variation ranged from -169.33% to 65.47% in inter-fraction CBCT and from -171.04% to 60.00% in intra-fraction CBCT. Inter-fraction liver position errors were significantly related to the setup errors. The relative diaphragm position was not statistically related to the baseline drifts in the inter-fraction nor in the intra-fraction. Conclusions: Using intra-fraction CBCT, significant amplitude variations and baseline drifts of respiratory motion were found compared with those in 4D CT. The relative diaphragm position in a single breathing cycle cannot reflect the liver position during dose delivery. At least a 6.8 mm PTV margin in the SI direction is recommended to compensate for the baseline drift.

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A Multi-Institutional Experience of MR-Guided Liver Stereotactic Body Radiation Therapy

Cited by 129 publications

References 41 publications

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

Real-time Magnetic Resonance-guided Liver Stereotactic Body Radiation Therapy: An Institutional Report Using a Magnetic Resonance-Linac System

Analysis of the Amplitude Changes and Baseline Drift of Respiratory Motion during Liver Stereotactic Body Radiation Therapy Based on Intra-Fraction CBCT

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