Technical Note: Rotational positional error corrected intrafraction set‐up margins in stereotactic radiotherapy: A spatial assessment for coplanar and noncoplanar geometry

Sarkar, Biplab; Munshi, Anusheel; Ganesh, T; Manikandan, A.; Krishnankutty, Saneg; Chitral, Latika; Pradhan, Anirudh; Mohanti, Bidhu Kalyan

doi:10.1002/mp.13810

Cited by 11 publications

(19 citation statements)

References 46 publications

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“…The maximum mean deviation in our study was -0.57 ± 0.85mm (z-direction). The maximum combined translational and rotational shifts reported by Sarkar et al (30) were -3.1mm and 4.2°, while we found 4.6mm and 1.6°i n our study. By analyzing the CBCT performed before and after IMRT treatment Den et al (32) reported the residual error frequencies ranging from 23.0% to 34.0% and 3.0% to 5.4% for >1mm and >3mm thresholds, while Lu et al (33) reported frequencies from 17.5% to 30.8% and from 0.0% to 4.5% for 1mm and 2mm thresholds using similar methods.…”

Section: Discussioncontrasting

confidence: 62%

“…Rosenfelder et al (29) reported up to -0.8 ± 0.7 mm positional shifts in the longitudinal direction for noncoplanar beams in external beam radiotherapy. Sarkar et al (30) reported an average shift of 0.6 ± 0.9mm in the lateral direction for noncoplanar beams in stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) using frameless setup. Lewis et al (31) reported an average shift of 0.55 ± 0.43 mm in the lateral direction for noncoplanar beams in SRS.…”

Section: Discussionmentioning

confidence: 99%

“…Sarkar et al. ( 30 ) reported an average shift of 0.6 ± 0.9mm in the lateral direction for noncoplanar beams in stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) using frameless setup. Lewis et al.…”

Section: Discussionmentioning

confidence: 99%

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Clinical Implementation of a 6D Treatment Chair for Fixed Ion Beam Lines

et al. 2021

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PurposeTo verify the practicality and safety of a treatment chair with six degrees of freedom (6DTC) through demonstrating the efficacy of the workflow in clinical settings and analyzing the obtained technical data, including intra-fraction patient movement during the use of the 6DTC.Materials and MethodsA clinical study was designed and conducted to test the clinical treatment workflow and the safety of the 6DTC. Based on the demonstrated dosimetric advantages, fifteen patients with head and neck tumors were selected and treated with the 6DTC. The positional error at the first beam position (PE-B1) and the second beam position (PE-B2) were analyzed and compared with the results from daily quality assurance (QA) procedures of the 6DTC and imaging system performed each day before clinical treatment. The intra-fraction patient movement was derived from the total patient alignment positional error and the QA data based on a Gaussian distribution formulism.ResultsThe QA results showed sub-millimeter mechanical accuracy of the 6DTC over the course of the clinical study. For 150 patient treatment fractions, the mean deviations between PE-B1 and PE-B2 were 0.13mm (SD 0.88mm), 0.25mm (SD 1.17mm), -0.57mm (SD 0.85mm), 0.02° (SD 0.35°), 0.00° (SD 0.37°), and -0.02° (SD 0.37°) in the x, y, z (translational), and u, v, w (rotational) directions, respectively. The calculated intra-fraction patient movement was -0.08mm (SD 0.56mm), 0.71mm (SD 1.12mm), -0.52mm (SD 0.84mm), 0.10° (SD 0.32°), 0.09° (SD 0.36°), and -0.04° (SD 0.36°) in the x, y, z, u, v, w directions, respectively.ConclusionsThe performance stability of the 6DTC was satisfactory. The position accuracy and intra-fraction patient movement in an upright posture with the 6DTC were verified and found adequate for clinical implementation.

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Section: Discussioncontrasting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

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Clinical Implementation of a 6D Treatment Chair for Fixed Ion Beam Lines

et al. 2021

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“…Hence, it is necessary to have high geometrical accuracy for a safe clinical application of precise radiotherapy. Some recent studies describe the process of measurement and reduction in geometrical errors [5][6][7]. There are some reviews which discuss different types of errors in radiotherapy and the process to overcome these discrepancies [3,[8][9][10].…”

Section: Related Workmentioning

confidence: 99%

“…Therefore, geometric errors have to be identified and removed for safe radiation therapy. There are many recent studies which address issues of measurement and the reduction in geometrical errors [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

A Sentence Classification Framework to Identify Geometric Errors in Radiation Therapy from Relevant Literature

Basu

Goldsworthy²,

Gkoutos

2021

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The objective of systematic reviews is to address a research question by summarizing relevant studies following a detailed, comprehensive, and transparent plan and search protocol to reduce bias. Systematic reviews are very useful in the biomedical and healthcare domain; however, the data extraction phase of the systematic review process necessitates substantive expertise and is labour-intensive and time-consuming. The aim of this work is to partially automate the process of building systematic radiotherapy treatment literature reviews by summarizing the required data elements of geometric errors of radiotherapy from relevant literature using machine learning and natural language processing (NLP) approaches. A framework is developed in this study that initially builds a training corpus by extracting sentences containing different types of geometric errors of radiotherapy from relevant publications. The publications are retrieved from PubMed following a given set of rules defined by a domain expert. Subsequently, the method develops a training corpus by extracting relevant sentences using a sentence similarity measure. A support vector machine (SVM) classifier is then trained on this training corpus to extract the sentences from new publications which contain relevant geometric errors. To demonstrate the proposed approach, we have used 60 publications containing geometric errors in radiotherapy to automatically extract the sentences stating the mean and standard deviation of different types of errors between planned and executed radiotherapy. The experimental results show that the recall and precision of the proposed framework are, respectively, 97% and 72%. The results clearly show that the framework is able to extract almost all sentences containing required data of geometric errors.

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Compatibility assessment of Varian and Elekta robotic couch‐assisted six‐dimensional patient positioning correction systems with external independent imaging modalities

Sarkar

Ganesh

Munshi

et al. 2021

Precision Radiation Oncology

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Aim This study aimed to evaluate the compatibility of robotic couch‐assisted six‐dimensional (6D) patient positioning systems with gantry‐mounted and in‐room independent imaging modalities in two different accelerators. Materials and Methods Imaging and 6D patient setup workflow were evaluated for both machines. The imaging workflow consists of onboard (OBI) cone beam computed tomography (CBCT) imaging and in‐room ExacTrac imaging to evaluate setup errors. Setup images were acquired using CBCT, and positional corrections were performed using a 6D robotic couch. Further compatibility of CBCT and ExacTrac was evaluated for both coplanar and noncoplanar beam geometries. Result Varian 6D couch, PerfectPitch, comprises three translational axes (x, y, z): the table column's rotational axis (yaw) and the two additional axes of rotation (pitch and roll) that are affected by the couch's bellows. In this approach, after accounting for 6D shifts, the couch remains physically rotated about its rotational axis (yaw:zROT ≠ 0°). This residual error in yaw rotation was counted in subsequent noncoplanar beam geometries. If the initial yaw couch error was −5.8°, after applying this error a beam planned at 30° couch rotation will appear as 24.2° (= 30°–5.8°) for both CBCT and ExacTrac images. In Elekta's HexaPOD six degrees of freedom (DoF) couch, the column rotational axis is not counted as one of the six DoF. Instead, HexaPOD's bellows can effectively execute all three rotations, and the 3D couch movements that correct setup errors are limited only to the translational axes. A noncoplanar beam planned at a couch rotation of 30° appeared at 30° after patient positional correction. Conclusion Varian 6D robotic couch solutions are only partially compatible with independent in‐room imaging systems.

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Technical Note: Rotational positional error corrected intrafraction set‐up margins in stereotactic radiotherapy: A spatial assessment for coplanar and noncoplanar geometry

Cited by 11 publications

References 46 publications

Clinical Implementation of a 6D Treatment Chair for Fixed Ion Beam Lines

Clinical Implementation of a 6D Treatment Chair for Fixed Ion Beam Lines

A Sentence Classification Framework to Identify Geometric Errors in Radiation Therapy from Relevant Literature

Compatibility assessment of Varian and Elekta robotic couch‐assisted six‐dimensional patient positioning correction systems with external independent imaging modalities

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