Commissioning, clinical implementation, and performance of the Mobetron 2000 for intraoperative radiation therapy

Wootton, Landon; Meyer, Juergen; Kim, Edward; Phillips, Mark H.

doi:10.1002/acm2.12027

Cited by 11 publications

(2 citation statements)

References 27 publications

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“…IOERT uses megavoltage electrons with energies between 4 and 12 MeV generated from a mobile electron accelerator, that is, equipped with beam‐shaping beveled applicators to conform radiation to the target shape (IntraOp Mobetron, IntraOp Medical Corporation, Sunnyvale, CA). 3 , 62 Beveled applicators allow larger target coverage but at the expense of a less uniform dose and reduced beam penetration in tissue. The electron energy is selected to cover the intended target with a 90% isodose plus a 0.1–0.5 cm safety margin.…”

Section: Iort Current Status and Future Directionsmentioning

confidence: 99%

Intraoperative radiation therapy with 50 kV x‐rays: A multi‐institutional review

Sethi,

Gros,

Brodin

et al. 2024

J Applied Clin Med Phys

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This report covers clinical implementation of a low kV intraoperative radiation therapy (IORT) program with the INTRABEAM® System (Carl Zeiss Meditec AG, Jena, Germany). Based on collective user experience from eight institutions, we discuss best methods of INTRABEAM quality assurance (QA) tests, commissioning measurements, clinical workflow, treatment planning, and potential avenues for research. The guide provides pertinent background information and clinical justification for IORT. It describes the INTRABEAM system and commissioning measurements along with a TG100 risk management analysis to ensure safety and accuracy of the IORT program. Following safety checks, dosimetry measurements are performed for verification of field flatness and symmetry, x‐ray output, and depth dose. Also discussed are dose linearity checks, beam isotropy, ion chamber measurements, calibration protocols, and in‐vivo dosimetry with optically stimulated luminescence dosimeters OSLDs, and radiochromic film. Emphasis is placed on the importance of routine QA procedures (daily, monthly, and annual) performed at regular intervals for a successful IORT program. For safe and accurate dose delivery, tests of important components of IORT clinical workflow are emphasized, such as, dose prescription, pre‐treatment QA, treatment setup, safety checks, radiation surveys, and independent checks of delivered dose. Challenges associated with in‐vivo dose measurements are discussed, along with special treatment procedures and shielding requirements. The importance of treatment planning in IORT is reviewed with reference to a Monte Carlo‐based commercial treatment planning system highlighting its main features and limitations. The report concludes with suggested topics for research including CT‐based image‐guided treatment planning and improved prescription dose accuracy. We hope that this multi‐institutional report will serve as a guidance document on the clinical implementation and use of INTRABEAM IORT.

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Section: Iort Current Status and Future Directionsmentioning

confidence: 99%

Intraoperative radiation therapy with 50 kV x‐rays: A multi‐institutional review

Sethi,

Gros,

Brodin

et al. 2024

J Applied Clin Med Phys

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“…The present study focuses on the Mobetron 1000 ® (Intraop Medical Corporation, Sunnyvale, CA, USA) that is able to produce electron beams with energies of 4, 6, 9 and 12 MeV. The new model, Mobetron 2000 [18], only produces electrons with nominal energies of 6, 9 and 12 MeV.…”

Section: Introductionmentioning

confidence: 99%

Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects

García-Cases

Pérez‐Calatayud²,

Ballester³

et al. 2018

J. Radiol. Prot.

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The aim of this work is to analyse the scattered radiation produced by the mobile accelerator Mobetron 1000. To do so, detailed Monte Carlo simulations using two different codes, Penelope2008 and Geant4, were performed. Measurements were also done. To quantify the attenuation due to the internal structures, present in the accelerator head, on the scattered radiation produced, some of the main structural shielding in the Mobetron 1000 has been incorporated into the geometry simulation. Results are compared with measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation component due to low energy scattered electrons. This encouraged us to perform additional calculations to separate the role played by this component. Ambient dose equivalent, H*(10), outside of the operating room (OR) has been evaluated using Geant4. H*(10) has been measured inside and outside the OR, being its values compatible with those reported in the literature once the low energy electron component is removed. With respect to the role played by neutrons, estimations of neutron H*(10) using Geant4 together with H*(10) measurements has been performed for the case of the 12 MeV electron beam. The values obtained agree with the experimental values existing in the literature, being much smaller than those registered in conventional accelerators. This study is a useful tool for the clinical user to investigate the radiation protection issues arising with the use of these accelerators in ORs without structural shielding. These results will also enable to better fix the maximum number of treatments that could be performed while insuring adequate radiological protection of workers and public in the hospital.

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Commissioning of an ultra‐high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols

et al. 2021

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Purpose To present the acceptance and the commissioning, to define the reference dose, and to prepare the reference data for a quality assessment (QA) program of an ultra‐high dose rate (UHDR) electron device in order to validate it for preclinical animal FLASH radiotherapy (FLASH RT) experiments and for FLASH RT clinical human protocols. Methods The Mobetron® device was evaluated with electron beams of 9 MeV in conventional (CONV) mode and of 6 and 9 MeV in UHDR mode (nominal energy). The acceptance was performed according to the acceptance protocol of the company. The commissioning consisted of determining the short‐ and long‐term stability of the device, the measurement of percent depth dose curves (PDDs) and profiles at two different positions (with two different dose per pulse regimen) and for different collimator sizes, and the evaluation of the variability of these parameters when changing the pulse width and pulse repetition frequency. Measurements were performed using a redundant and validated dosimetric strategy with alanine and radiochromic films, as well as Advanced Markus ionization chamber for some measurements. Results The acceptance tests were all within the tolerances of the company's acceptance protocol. The linearity with pulse width was within 1.5% in all cases. The pulse repetition frequency did not affect the delivered dose more than 2% in all cases but 90 Hz, for which the larger difference was 3.8%. The reference dosimetry showed a good agreement within the alanine and films with variations of 2.2% or less. The short‐term (resp. long‐term) stability was less than 1.0% (resp. 1.8%) and was the same in both CONV and UHDR modes. PDDs, profiles, and reference dosimetry were measured at two positions, providing data for two specific dose rates (about 9 Gy/pulse and 3 Gy/pulse). Maximal beam size was 4 and 6 cm at 90% isodose in the two positions tested. There was no difference between CONV and UHDR mode in the beam characteristics tested. Conclusions The device is commissioned for FLASH RT preclinical biological experiments as well as FLASH RT clinical human protocols.

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Commissioning, clinical implementation, and performance of the Mobetron 2000 for intraoperative radiation therapy

Cited by 11 publications

References 27 publications

Intraoperative radiation therapy with 50 kV x‐rays: A multi‐institutional review

Intraoperative radiation therapy with 50 kV x‐rays: A multi‐institutional review

Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects

Commissioning of an ultra‐high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols

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