University Hospital Lausanne (CHUV)
Institute of Radiation Physics
Raphaël Moeckli completed his MSc degree in Ecole Polytechnique Fédérale de Lausanne and his PhD in medical imaging at the University of Lausanne in 2001. He is a certified Swiss medical physicist since 1999, head of the radiation therapy group in the Institute of Radiation Physics and head physicist in the Radio-Oncology Department in CHUV Lausanne since 2001. He has been appointed associate professor at the University of Lausanne in 2021. Raphaël is an associate professor at Lausanne University since 2021. His main fields of research are FLASH radiotherapy, tomotherapy and multicriteria optimisation.

Presenter Of 1 Presentation

Beam Monitoring for Clinical Translation of Ultra-High Dose Rate Electron Therapy

Session Type
Industry Sponsored Session
Date
Thu, 02.12.2021
Session Time
12:15 - 12:45
Room
Room 2.15
Lecture Time
12:15 - 12:30

Author Of 2 Presentations

Beam Monitoring for Clinical Translation of Ultra-High Dose Rate Electron Therapy

Session Type
Industry Sponsored Session
Date
Thu, 02.12.2021
Session Time
12:15 - 12:45
Room
Room 2.15
Lecture Time
12:15 - 12:30

CAN UHDR VHEE DEVICES WITH ONLY A FEW FIXED BEAMS PROVIDE COMPETITIVE TREATMENT PLANS COMPARED TO VMAT ?

Session Type
FLASH Modalities Track (Oral Presentations)
Date
Thu, 02.12.2021
Session Time
11:00 - 12:00
Room
Hall C
Lecture Time
11:50 - 12:00

Abstract

Background and Aims

Future RT devices using very-high energy electrons (VHEE) (50-250MeV) may produce suitable beams to treat deep-seated tumours conformally and at ultra-high dose rates (UHDR) capable of triggering the FLASH effect. The FLASH effect has been observed for large doses delivered with overall treatment times less than 200ms. Such treatment durations do not allow the use of a movable gantry and multiple fixed beam lines (FBL) become mandatory. This treatment planning study evaluates VHEE dose distributions in patients using a varying number of FBL with different energies and source-axis-distances (SAD). The minimum requirements for delivering conformal VHEE RT comparable to conventional VMAT plans and trade-offs between plan quality and number of beam lines are assessed.

Methods

We performed VHEE and VMAT treatment planning for multiple indications (glioblastoma, mediastinum, lung, prostate) using RayStation (research version) and compared the dosimetric quality of VHEE plans to VMAT while assessing the impact of arrangement and number of FBL, beam energies, and SAD.

Results

Most substantial coverage and conformity improvement is achieved when increasing the beam energy from 50 to 100MeV. Further improvement is obtained specifically for deep-seated targets (>10-15cm) when increasing energies further to 200MeV. While VHEE plans using 16 coplanar beams outperform VMAT plans, we found that VHEE plans using only 3-5 beams have DVH metrics that are comparable to VMAT plans. Beams with SAD>1m are preferable for treatments using few beams.

Conclusions

UHDR VHEE devices with only a few FBL may provide competitive dosimetric conformity that may be additionally enhanced by the FLASH effect.

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