A treatment planning comparison between a novel rotating gamma system and robotic linear accelerator based intracranial stereotactic radiosurgery/radiotherapy

Sun

et al. 2022

Preprint

Purpose: TaiChi, a new multi-modality radiotherapy platform that integrates a linear accelerator, a focusing gamma system, and a kV imaging system within an enclosed O-ring gantry, was introduced into clinical application. This work aims to assess the technological characteristics and commissioning results of the TaiChi platform. Methods: The acceptance testing and commissioning were performed following the manufacturer’s customer acceptance tests (CAT) and several AAPM Task Groups (TG) reports/guidelines. Regarding the linear accelerator(linac), all applicable validation measurementsrecommended by the MPPG 5.a (basic photon beam model validation, intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) validation, end-to-end(E2E) tests, and patient-specific quality assurance (QA)) were performed. For the focusing gamma system, the absorbed doses were measured using a PTW31014 ion chamber (IC) and PTW60016 diode detector. EBT3 films and a PTW60016 diode detector were employed to measure the relative output factors (ROFs). The E2E tests were performed using PTW31014 IC and EBT3 films. The coincidences between the imaging isocenter and the linac/gamma treatment isocenter were investigated using EBT3 films. The image quality was evaluated regarding the contrast-to-noise ratio (CNR), spatial resolution, and uniformity. Results: All tests included in the CAT met the manufacturer’s specifications. All MPPG 5.a measurements complied with the tolerances. The confidence limits for IMRT/VMAT point dose and dose distribution measurements were achieved according to TG-119. The point dose differences were below 1.68% and gamma passing rates were above 95.9% for the linac E2E tests. All plans of patient-specific QA had point dose differences below 1.79% and gamma passing rates above 96.1% using the 3%/2 mm criterion suggested by TG-218. For the focusing gamma system, the differences between the calculated and measured absorbed doses were below 1.86%. The ROFs calculated by the TPS were independently confirmed within 2% using EBT3 films and a PTW60016 detector. The point dose differences were below 2.57% and gamma passing rates were above 95.3% using the 2%/1 mm criterion for the E2E tests. The coincidences between the imaging isocenter and the linac/gamma treatment isocenter were within 0.5 mm. The image quality parameters fully complied with the manufacturer’s specifications regarding the CNR, spatial resolution, and uniformity. Conclusion: The multi-modality radiotherapy platform complies with the CAT and AAPM commissioning criteria. The commissioning results demonstrate that this platform performs well in mechanical and dosimetry accuracy.

Section: Discussionmentioning

confidence: 99%

Characterization and commissioning of a new collaborative multi-modality radiotherapy platform

Sun

et al. 2022

Preprint

“…CK is an image-guided frameless robotic technology designed to deliver non-isocenter non-coplanar beam, and the entire treatment procedure is completely non-invasive [76]. Despite the differences in treatment planning and dose delivery significant differences were not found in the quality of clinical outcome between GK and CK after SRS [77,78].…”

Section: Radiotherapy Techniquesmentioning

confidence: 99%

The role of brain radiotherapy for EGFR- and ALK-positive non-small-cell lung cancer with brain metastases: a review

et al. 2023

Non-small cell lung cancer (NSCLC) is frequently complicated by central nervous system (CNS) metastases affecting patients’ life expectancy and quality. At the present clinical trials including neurosurgery, radiotherapy (RT) and systemic treatments alone or in combination have provided controversial results. CNS involvement is even more frequent in NSCLC patients with EGFR activating mutations or ALK rearrangement suggesting a role of target therapy in the upfront treatment in place of loco-regionals treatments (i.e. RT and/or surgery). So far clinical research has not explored the potential role of accurate brain imaging (i.e. MRI instead of the routine total-body contrast CT and/or PET/CT staging) to identify patients that could benefit of local therapies. Moreover, for patients who require concomitant RT there are no clear guidelines on the timing of intervention with respect to innovative precision medicine approaches with Tyrosine Kinase Inhibitors, ALK-inhibitors and/or immuno-oncological therapies. On this basis the present review describes the therapeutic strategies integrating medical and radiation oncology in patients with metastatic NSCLC (mNSCLC) adenocarcinoma with CNS involvement and EGFR activating mutations or ALK rearrangement.

Mathews Journal of Cancer Science

“…Gamma ray systems are ideal for SRS and SBRT for small tumors. Novel designs using multiple rotating gamma sources and image guidance are available for clinical applications of both intracranial and extracranial sites (the CybeRay system) [5].…”

Section: Srs and Sbrt Equipmentmentioning

confidence: 99%

Physics and Dosimetric Principles of SRS and SBRT

Charlie¹

2019

This paper reviews the radiation physics and dosimetric principles of stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Recent radiation therapy physics and technology developments are reviewed followed by a brief description of the equipment available for SRS and SBRT. The treatment planning process and beam orientation optimization for SRS and SBRT are discussed. The dose calculation algorithms for radiation therapy are described including simple correction-based methods, advanced model-based algorithms and Monte Carlo simulations. Guidelines for SRS and SBRT treatment planning and plan evaluation are summarized including detailed dose prescription, organ dose tolerance and plan acceptance criteria. Finally, dosimetry measurements for SRS and SBRT are discussed with a focus on small field dosimetry.