Comparing the dosimetric characteristics of the electron beam from dedicated intraoperative and conventional radiotherapy accelerators

Baghani, Hamid Reza; Aghamiri, Seyed Mahmoud Reza; Mahdavi, Seied Rabi; Akbari, Mohammad Esmail

doi:10.1120/jacmp.v16i2.5017

Cited by 39 publications

(39 citation statements)

References 26 publications

(39 reference statements)

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“…Radiofrequency power is supplied by an E2V magnetron MG6090 (21). Pulse repetition frequency (PRF) could be varied from 1 to 60 Hz (1). Electron beam collimation system consists of two parts: a holder that is attached to the head of the accelerator and an applicator section that is in contact with the patient and holder.…”

Section: Liac Iort Acceleratormentioning

confidence: 99%

“…Intraoperative radiation therapy (IORT) is an innovative treatment technique that delivers a large single fraction of radiation dose to the tumor bed during surgery (1,2). This kind of radiotherapy could be implemented by three different modalities including high-dose rate brachytherapy (HDR-IORT), low kV-IORT and intraoperative electron radiation therapy (IOERT) (3).…”

Section: Introductionmentioning

confidence: 99%

“…This kind of radiotherapy could be implemented by three different modalities including high-dose rate brachytherapy (HDR-IORT), low kV-IORT and intraoperative electron radiation therapy (IOERT) (3). Due to the limited range of electron beam and short treatment time, IO-ERT is the main of interest (1).…”

Section: Introductionmentioning

confidence: 99%

“…Using the ionization chambers for dose measurements and calibration of high dose per pulse electron beam needs an appropriate method to precisely determine the ion recombination correction factor (K sat ) of employed ion chamber (8). Using two voltage analysis (TVA) method, which is recommended by IAEA (Technical report series), TRS-398, and American Association of Physicists in Medicine (AAPM) (Task group) TG-51 protocols causes some degree of uncertainty in K sat determination (1,(9)(10)(11). This uncertainty in the determination of recombination correction factor of ions formed in the chamber sensitive volume is due to the fact that the free electron fraction created in the chamber sensitive volume is not taken into account during determination of recombination correction factor using the TVA method (12,13).…”

Section: Introductionmentioning

confidence: 99%

“…This uncertainty in the determination of recombination correction factor of ions formed in the chamber sensitive volume is due to the fact that the free electron fraction created in the chamber sensitive volume is not taken into account during determination of recombination correction factor using the TVA method (12,13). Therefore, the extended Boag theory and Laitano or Di Martino formalism must be applied to determine the recombination correction factor of ion chambers used for calibration of intraoperative radiotherapy electron beams (1,(14)(15)(16). As an alternative, one can choose a dosimeter that has an independent dose rate response (17,18).…”

Section: Introductionmentioning

confidence: 99%

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Output Factor Measurement of a Dedicated Intra-Operative Radiotherapy (IORT) Accelerator Using Ethanol Chlorobenzene (ECB) Dosimeter and Comparing the Results with Ionometric Dosimetry and Monte Carlo Simulation

et al. 2016

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Background: The accurate dose delivery in intraoperative radiotherapy (IORT) tightly depends on the precision of measured dose by the ion chamber. Output factor (OF) measurement of dedicated intraoperative electron radiotherapy (IOERT) accelerators using ion chamber faces some technical challenges including determination of Ksat. Objectives: The goal was to evaluate the performance of ethanol chlorobenzene (ECB) dosimeter in measuring the OF of intraoperative electron beam and to compare the results to those of ionometric dosimetry and Monte Carlo simulation. Consequemtly we determined the Ksat of employed ion chamber through comparison of the ECB response to ion chamber. Materials and Methods: LIAC dedicated accelerator (LIAC Sordina SpA, Italy) was used for irradiation. To calculate the Ksat, ECB and Advanced Markus chamber were placed at the depth of maximum dose for different energies of LIAC accelerator. Then, Ksat was calculated through comparison of the obtained results. To measure the OF of electron beam, ECB was placed at the depth of maximum dose for each combination of energy/applicator size, and the absorbed dose was determined. Obtained results were compared to those of Advanced Markus chamber and Monte Carlo simulation. Results: The results of Ksat measurement showed that there is a very good agreement between the practically obtained Ksat and theoretical values determined by Laitano formalism at different energies (the maximum difference between the results was lower than 1%). The results of ECB OF measurement were in accordance to the results of ionometric dosimetry and Monte Carlo simulation (the maximum difference between the results was about 1.5% and 1.7%, respectively). Conclusion: Based on the results, it may be concluded that the ECB dosimeter could be considered as an accurate tool for both OF measurement of intraoperative electron beam and cross calibration of employed ion chambers for absolute dosimetry (determination of the Ksat).

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Section: Liac Iort Acceleratormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Output Factor Measurement of a Dedicated Intra-Operative Radiotherapy (IORT) Accelerator Using Ethanol Chlorobenzene (ECB) Dosimeter and Comparing the Results with Ionometric Dosimetry and Monte Carlo Simulation

et al. 2016

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Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

Baghani

Robatjazi

2023

J Applied Clin Med Phys

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Background and ObjectiveAvoiding the underlying healthy tissue over‐exposure during breast intraoperative electron radiotherapy (IOERT) is owing to the use of some dedicated radioprotection disks during patient irradiation. The originated contaminant photons from some widely used double‐layered shielding disks including PMMA+Cu, PTFE+steel, and Al+Pb configurations during the breast IOERT have been evaluated through a Monte Carlo (MC) simulation approach.MethodsProduced electron beam with energies of 6, 8, 10, and 12 MeV by a validated MC model of Liac12 dedicated IOERT accelerator was used for disk irradiations. Each of above‐mentioned radioprotection disks was simulated inside a water phantom, so that the upper disk surface was positioned at R90 depth of each considered electron energy. Simulations were performed by MCNPX (version 2.6.0) MC code. Then, the energy spectra of the contaminant photons at different disk surfaces (upper, middle, and lower one) and relevant contaminant dose beneath the studied disks were determined and compared.ResultsNone of studied shielding disks show significant photon contamination up to 10 MeV electron energy, so that the induced photon dose by the contaminant X‐rays was lower than those observed in the disk absence under the same conditions. In return, the induced photon dose at a close distance to the lower disk surface exceeded from calculated values in the disk absence at 12 MeV electron energy. The best performance in contaminant dose reduction at the energy range of 6–10 MeV belonged to the Al+Pb disk, while the PMMA+Cu configuration showed the best performance in this regard at 12 MeV energy.ConclusionFinally, it can be concluded that all studied shielding disks not only don't produce considerable photon contamination but also absorb the originated X‐rays from electron interactions with water at the electron energy range of 6–10 MeV. The only concern is related to 12 MeV energy where the induced photon dose exceeds the dose values in the disk absence. Nevertheless, the administered dose by contaminant photons to underlying healthy tissues remains beneath the tolerance dose level by these organs at the entire range of studied electron energies.

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Monte Carlo-based determination of radiation leakage dose around a dedicated IOERT accelerator

Baghani

Aghdam

Robatjazi

et al. 2019

Radiat Environ Biophys

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Comparing the dosimetric characteristics of the electron beam from dedicated intraoperative and conventional radiotherapy accelerators

Cited by 39 publications

References 26 publications

Output Factor Measurement of a Dedicated Intra-Operative Radiotherapy (IORT) Accelerator Using Ethanol Chlorobenzene (ECB) Dosimeter and Comparing the Results with Ionometric Dosimetry and Monte Carlo Simulation

Output Factor Measurement of a Dedicated Intra-Operative Radiotherapy (IORT) Accelerator Using Ethanol Chlorobenzene (ECB) Dosimeter and Comparing the Results with Ionometric Dosimetry and Monte Carlo Simulation

Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

Monte Carlo-based determination of radiation leakage dose around a dedicated IOERT accelerator

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