Dose fall-off patterns with volumetric modulated arc therapy and three-dimensional conformal radiotherapy including the “organ at risk” effect. Experience of linear accelerator-based frameless radiosurgery from a single institution

Munshi, Anusheel; Sarkar, Biplab; Roy, Sunanda; Ganesh, T; Mohanti, Bidhu Kalyan

doi:10.1016/j.canrad.2018.10.003

Cited by 16 publications

(7 citation statements)

References 21 publications

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“…From the treatment approved plan, CT images were pushed to ExacTrac and CBCT workstations for set‐up verification. Details of radiotherapy treatment planning can be found elsewhere …”

Section: Methodsmentioning

confidence: 99%

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

et al. 2019

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Purpose: The aim of this study is to calculate setup margin based on six-dimensional (6D) corrected residual positional errors from kV cone beam computed tomography (CBCT) and from intrafraction projection kV imaging in coplanar and in noncoplanar couch positions in stereotactic radiotherapy. Methods: Six dimensional positional corrections were carried out before patient treatments, using a robotic couch and CBCT matching. A CBCT and stereoscopic ExacTrac image were acquired posttable position correction. Further, a series of intrafraction ExacTrac images were obtained for the variable couch position. Translational and rotational errors were identified as lateral (X), longitudinal (Y), vertical (Z); roll (Ɵ°), pitch (Φ°) and yaw (Ψ°). A total of 699 intrafraction image sets (361 coplanar and 338 noncoplanar) for 51 SRS/SRT patients were analysed. Rotational errors were corrected in terms of translational coordinates. Residual set-up margins were calculated from CBCT shifts. ExacTrac shifts give residual + intrafraction setup margins as a function of coplanar and noncoplanar couch positions. Results: The average residual positional error obtained from CBCT in X, Y, Z, Ɵ, Φ, Ψ were 0.1 AE 0.4 mm, 0.0 AE 0.6 mm, 0.0 AE 0.5 mm, 0.2 AE 0.8°, 0.1 AE 0.6°and À0.1 AE 0.7°respectively. For ExacTrac, the shits were À0.5 AE 0.9 mm, À0.0 AE 1mm, À0.6 AE 1.0mm, 0.4 AE 0.9°, À0.2 AE 0.6°, and À0.0 AE 0.8°.CBCT calculated linear setup margins in X, Y, Z direction were 0.5, 1.2, and 1 mm respectively. ExacTrac yielded coplanar and noncoplanar linear setup margins were 1.2, 1.3, 1.5, 1.4, 1.5, and 2.1 mm respectively. Conclusion: CBCT-based gross residual set-up margin is equal to 1 mm. ExacTrac calculated residual plus intrafraction setup margin falls within a 2 mm range; attributed to intrafraction patient movement, table position inaccuracies, and poor image fusion in noncoplanar geometry. There could be variations in the required additional margin between centers and between machines, which require further studies.

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“…From the treatment approved plan, CT images were pushed to ExacTrac and CBCT workstations for set‐up verification. Details of radiotherapy treatment planning can be found elsewhere …”

Section: Methodsmentioning

confidence: 99%

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

et al. 2019

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“…Munshi et al [30] evaluated the dose fall-off pattern for linear accelerator based on frameless stereotactic radiotherapy and radiosurgery using two different techniques, three-dimensional conformal radiotherapy and volumetric modulated arc therapy. Their results showed similar 100-80%, 100-50%, 100-20% distance values.…”

Section: Resultsmentioning

confidence: 99%

Feasibility and potential advantages using VMAT in SRS metastasis treatments

Pérez-Calatayud

Menéndez

Celada-Alvarez

et al. 2021

Rep Pract Oncol Radiother.

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background: Utilization of stereotactic radiosurgery (srs) for brain metastases (BM) has become the technique of choice as opposed to whole brain radiation therapy (WBrT). The aim of this work is to evaluate the feasibility and potential benefits in terms of normal tissue (NT) and dose escalation of volumetric modulated arc therapy (VMaT) in srs metastasis treatment. a VMaT optimization procedure has therefore been developed for internal dose scaling which minimizes planner dependence. Materials and methods:Five patient-plans incorporating treatment with frame-based srs with dynamic conformal arc technique (Da) were re-planned for VMaT. The lesions selected were between 4-6 cm 3 . The same geometry used in the Da plans was maintained for the VMaT cases. a VMaT planning procedure was performed attempting to scale the dose in inner auxiliary volumes, and to explore the potential for dose scaling with this technique. comparison of dose-volume histogram (DVh) parameters were obtained. results: VMaT allows a superior NT sparing plus conformity and dose scaling using the auxiliary volumes. The VMaT results were significantly superior in NT sparing, improving both the V 10 and V 12 values in all cases, with a 2-3 cm 3 saving. In addition, VMaT improves the dose coverage D 95 by about 0.5 Gy. The objective of dose escalation was achieved with VMaT with an increment of the Dmean and the Dmedian of about 2 Gy. conclusions: This work shows a benefit of VMaT in srs treatment with significant NT sparing. a VMaT optimization procedure, based on auxiliary inner volumes, has been developed, enabling internal dose escalation.

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“…The waiting period for SRS/SRT patients did not deviate significantly from the rest of the modalities of treatment, for example, IMRT, RA and 3DCRT. 11,12 According to Huang et al, patients appear content if they do not have to wait more than 37 min if they arrive on time and 63 min if they arrive late. 13 Patient wait time determination was the interest for this study in a department where the average daily workload per machine is between 15 and 20 patients in a paperless environment.…”

Section: Discussionmentioning

confidence: 99%

Patient wait times for daily outpatient radiotherapy appointments (a single-centre study)

Roy

Sarkar²,

Pradhan³

et al. 2023

J Radiother Pract

Self Cite

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Purpose: Patient wait time for every single fraction of every patient treated at our centre for the past year has been presented in this study. The waiting time data were analysed across different treatment sites and modalities. Materials and Methods: Between March 2021 and March 2022, all patients and their corresponding recorded measurements of waiting time were analysed. Times recorded included check-in time (CK), scheduled time to start treatment (SC) and beam-on time for the first beam of therapy (ST). SPSS version 18 was used for statistical calculations, correlations and assessing significance. Results: A total of 181 patients were treated during this duration. The total number of radiotherapy (RT) sessions recorded was 3011. Out of these 3011 sessions, number of times treated by rapid arc (RA), intensity-modulated radiotherapy (IMRT), three-dimensional conformal radiotherapy (3DCRT), stereotactic body radiotherapy (SBRT), stereotactic radiosurgery and stereotactic radiotherapy (SRS/SRT) were 68.18%, 30.19%, 0.167%, 0.565% and 0.19%, respectively. The mean (± standard deviation) times for scheduled time to start treatment (SC) to check-in time (CK), SC to ST (beam-on time for the first beam of treatment), CK to ST and (CK or SC) to ST were −14 ± 48 min, 6 ± 50 min, 19 ± 24 min and −4 ± 31 min, respectively. Conclusion: Patient wait times during RT were presented in this study. This study covered the daily waiting times before RT during modern-day RT treatment sessions. This vast series of consecutive patient data will be a valuable resource for the future planning and management of any modern RT department.

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Dose fall-off patterns with volumetric modulated arc therapy and three-dimensional conformal radiotherapy including the “organ at risk” effect. Experience of linear accelerator-based frameless radiosurgery from a single institution

Cited by 16 publications

References 21 publications

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

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

Feasibility and potential advantages using VMAT in SRS metastasis treatments

Patient wait times for daily outpatient radiotherapy appointments (a single-centre study)

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