Forward treatment planning for modulated electron radiotherapy (MERT) employing Monte Carlo methods

Henzen, Dominik; Manser, Peter; Frei, D.; Volken, W.; Neuenschwander, H.; Born, E; Lössl, Kristina; Aebersold, Daniel M.; Stampanoni, Marco; Fix, M.K.

doi:10.1118/1.4866227

Cited by 13 publications

(12 citation statements)

References 52 publications

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“…With IMRT/VMAT technique, excellent target coverage and dose homogeneity can be achieved, but in general, even with DIBH, the mean heart dose for left sided cases is above 5Gy 5,11,14,15 . Research and development has also been active in the area of modulated electron radiotherapy [17][18] and mixed electronphoton radiation therapy optimization [19][20] to potentially improve dosimetric parameters for complex chest wall irradiation.…”

Section: Discussionmentioning

confidence: 99%

Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm

et al. 2018

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For left-sided postmastectomy patients requiring chest wall plus comprehensive nodal irradiation, sometimes traditional techniques such as partial wide tangents or electron/tangents combination are not feasible due to abnormal chest wall contour or heart position or unusually wide excision scar. We developed electron chest wall irradiation technique using Electron Monte Carlo (EMC) dose algorithm that will achieve heart sparing with acceptable ipsilateral lung dose, minimal contralateral lung, and breast dose. Ten left-sided postmastectomy patients with very challenging anatomy were selected for this dosimetry study. The en face electron fields were designed from a single isocenter and gantry angle with different energy beams using different cutouts that matched on the skin. Smaller energy was used in the central thin chest wall part and higher energy in the medial internal mammary nodes (IMN) area, superior part of the thick chest wall, and/or axillary nodal area. The electron fields were matched to the photon supraclavicular field in the superior region. Daily field junctions were used to feather the match lines between all the fields. Electron field dose calculations were done with Monte Carlo. Five patients' chest wall fields were planned with 6/9MeVcombination, 1 with 6/12 MeV, 2 with 9/12 MeV, 1 with 9/16 MeV, and 1 with 6/9/12 MeV. Institutional criteria of prescription dose of 50 Gy for target volumes and normal tissue dose were met with this technique in spite of the challenging anatomy. Mean heart dose averaged 3.0 Gy ± 0.8 Gy. For ipsilateral lung, V20Gy and V5Gy averaged 33.2% ± 4.5% and 64.6% ± 9.6%, respectively. For contralateral lung, V5Gy averaged 5.1% ± 5.0%. For contralateral breast, V5Gy averaged 3.3% ± 3.1%. The electron chest wall irradiation technique using EMC dose algorithm can provide adequate dose coverage to the chest wall, IMNs, and/or axillary nodes while achieving heart sparing with acceptable ipsilateral lung dose, minimal contralateral lung, and breast dose.

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Section: Discussionmentioning

confidence: 99%

Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm

et al. 2018

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“…However, some methods of ensuring conformal dose delivery to patients may require further investigation of whether the FLASH effect will be achieved and its overall value to ensure superior outcome for patients. For example, there are studies demonstrating the feasibility and use of modulated electron RT, which utilised MLC (sometimes placed close to the patient) to achieve conformal dose to the patient [34,35]. As the HEE delivery machines currently deliver beam pulses every few milliseconds, and the pulses are typically on the order of one or more Gray-per-pulse, this would require a very fast moving MLC to achieve the desired field modulation and such a technology is not currently yet available [36].…”

Section: Uhdr Hee Delivery Techniques and Challengesmentioning

confidence: 99%

FLASH radiotherapy treatment planning and models for electron beams

Rahman

Trigilio

Franciosini

et al. 2022

Radiotherapy and Oncology

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“…There have been several approaches proposed to utilize electron beams with dynamic collimation, but some require new hardware 1 , 2 , 3 (e.g., an electron‐multi‐leaf collimator [MLC]) and/or enhanced delivery capacities 4 , 5 , 6 , 7 , 8 utilizing the existing photon‐MLC to collimate the electron beam. The dynamic collimation of electrons can be classified as either modulated electron radiation therapy (MERT) or modulated photon and electron conformal therapy (MPERT), which have been shown to reduce dose to organs at risk and improve dose conformity in breast, 8 , 9 , 10 , 11 postmastectomy chest‐wall, 12 , 13 head and neck, 14 , 15 and scalp 16 over conventional electron or photon IMRT treatments in retrospective planning studies. These techniques achieve better dose conformity than standard electron‐cutout collimation while maintaining the primary advantage of electron dose falloff in the depth direction.…”

Section: Introductionmentioning

confidence: 99%

A fast GPU‐accelerated Monte Carlo engine for calculation of MLC‐collimated electron fields

2022

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Background: Although intensity-modulated radiation therapy and volumetric arc therapy have revolutionized photon external beam therapies, the technological advances associated with electron beam therapy have fallen behind. Modern linear accelerators contain technologies that would allow for more advanced forms of electron treatments, such as beam collimation, using the conventional photon multi-leaf collimator (MLC); however, no commercial solutions exist that calculate dose from such beam delivery modes. Additionally, for clinical adoption to occur, dose calculation times would need to be on par with that of modern dose calculation algorithms. Purpose: This work developed a graphics processing unit (GPU)-accelerated Monte Carlo (MC) engine incorporating the Varian TrueBeam linac head geometry for a rapid calculation of electron beams collimated using the conventional photon MLC. Methods: A compute unified device architecture framework was created for the following: (1) transport of electrons and photons through the linac head geometry, considering multiple scattering, Bremsstrahlung, Møller, Compton, and pair production interactions; (2) electron and photon propagation through the CT geometry, considering all interactions plus the photoelectric effect; and (3) secondary particle cascades through the linac head and within the CT geometry. The linac head collimating geometry was modeled according to the specifications provided by the vendor, who also provided phase-space files. The MC was benchmarked against EGSnrc/DOSXYZnrc/GEANT by simulating individual interactions with simple geometries, pencil, and square beam dose calculations in various phantoms. MC-calculated dose distributions for MLC and jaw-collimated electron fields were compared to measurements in a water phantom and with radiochromic film. Results: Pencil and square beam dose distributions are in good agreement with DOSXYZnrc. Angular and spatial distributions for multiple scattering and secondary particle production in thin slab geometries are in good agreement with EGSnrc and GEANT. Dose profiles for MLC and jaw-collimated 6-20-MeV electron beams showed an average absolute difference of 1.1 and 1.9 mm for the FWHM and 80%-20% penumbra from measured profiles. Percent depth doses showed differences of <5% for as compared to measurement. The computation time on an NVIDIA Tesla V100 card was 2.5 min to achieve a dose uncertainty of <1%, which is ∼300 times faster than published results in a similar geometry using a single-CPU core.

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Forward treatment planning for modulated electron radiotherapy (MERT) employing Monte Carlo methods

Cited by 13 publications

References 52 publications

Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm

Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm

FLASH radiotherapy treatment planning and models for electron beams

A fast GPU‐accelerated Monte Carlo engine for calculation of MLC‐collimated electron fields

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