Journal Article

Exploring the advantages of intensity-modulated proton therapy: experimental validation of biological effects using two different beam intensity-modulation patterns

Yiu, Joycelyn, Geng, Changran, Wang, Xiaochun, Chen, Mei, Grosshans, David R., Mohan, Radhe, Bronk, Lawrence, Zhang, Xiaodong, Kerr, Matthew, Sahoo, Narayan, Stephan, Clifford, Ma, Duo, Cao, Wenhua, Sobieski, Mary, Guan, Fada

2020

Overview

In current treatment plans of intensity-modulated proton therapy, high-energy beams are usually assigned larger weights than low-energy beams. Using this form of beam delivery strategy cannot effectively use the biological advantages of low-energy and high-linear energy transfer (LET) protons present within the Bragg peak. However, the planning optimizer can be adjusted to alter the intensity of each beamlet, thus maintaining an identical target dose while increasing the weights of low-energy beams to elevate the LET therein. The objective of this study was to experimentally validate the enhanced biological effects using a novel beam delivery strategy with elevated LET. We used Monte Carlo and optimization algorithms to generate two different intensity-modulation patterns, namely to form a downslope and a flat dose field in the target. We spatially mapped the biological effects using high-content automated assays by employing an upgraded biophysical system with improved accuracy and precision of collected data. In vitro results in cancer cells show that using two opposed downslope fields results in a more biologically effective dose, which may have the clinical potential to increase the therapeutic index of proton therapy.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/57/2266 / 692/308/575 / Algorithms / Biological effects / Cancer therapies / Cell Line, Tumor / Clinical medicine / Drug dosages / Energy / Energy transfer / Humanities and Social Sciences / Humans / Linear Energy Transfer / Male / Medical research / Monte Carlo Method / multidisciplinary / Optimization / Photons / Planning / Prostatic Neoplasms - radiotherapy / Proton Therapy - methods / Protons / Radiation therapy / Radiotherapy Dosage / Radiotherapy Planning, Computer-Assisted - methods / Radiotherapy, Intensity-Modulated - methods / Science / Science (multidisciplinary) / Translational Research, Biomedical - methods / Tumors