ESTRO 2025 - Abstract Book

S24

Invited Speaker

ESTRO 2025

with advanced mathematical methods could streamline decision-making processes, automate routine tasks, and significantly enhance efficiency, accuracy, and speed in adaptive proton therapy.

Rather than competing with existing radiotherapy methods, online APT complements current radiotherapy technologies, especially when reduction of robustness settings and integration of novel proton technologies are still under active investigation. APT expands the unique advantages of proton therapy, such as reduced radiation exposure to non-target tissues, particularly crucial in pediatric oncology or tumors near sensitive structures. Therefore, Adaptive Proton Therapy constitutes a pivotal advancement in personalized cancer treatment, accommodating dynamic anatomical, dosimetric, and biological changes throughout therapy. By effectively adapting to these variations, APT ensures precise dose delivery, optimizes tumor control, minimizes side effects, and ultimately enhances the overall efficacy, safety, and quality of proton therapy treatments.

4683

Speaker Abstracts Pushing the potential of electron RT on standard linacs Silvan Mueller Division of Medical Radiation Physics, Inselspital - University Hospital Bern, Bern, Switzerland

Abstract:

Electron beams (4–22 MeV) available on standard C-arm linacs are commonly used for treating certain superficial targets due to their favorable distal dose fall-off. However, conventional treatment planning, which typically employs a single field collimated by a cut-out within an applicator, is dosimetrically suboptimal and clinically cumbersome. Integrating a modern collimation device, such as a multileaf collimator (MLC), could enable multiple electron field delivery with intensity and energy modulation. Additionally, simultaneous optimization of photon and electron beams could leverage the advantages of both modalities within a single treatment plan on the same linac. This talk explores advanced electron beam delivery and planning techniques to enhance treatment efficacy and clinical workflow on standard linacs.

4684

Speaker Abstracts The next frontier with (VHE)E Jake Harold Pensavalle CPFR, Centro Pisano Flash Radiotherapy, Pisa, Italy. Research and Development, Sordina IORT Technologies S.p.A., Rome, Italy

Abstract:

Very high energy electrons (VHEE) have recently emerged as a key enabler of FLASH radiotherapy, offering a promising pathway toward treating deep-seated tumors with ultra-high dose rates. FLASH therapy, which delivers doses on the order of tens of Gy per second, has shown unique biological benefits in normal tissue sparing; however, extending these benefits beyond superficial lesions remains challenging. Intraoperative electron radiotherapy (IOeRT), utilizing mobile electron linacs, provides a valuable precursor technology, as it already achieves high instantaneous dose rates in a single fraction. Building on this foundation, low-energy electron FLASH