Radiobiology of Particle Therapy: Revisiting the Preclinical Knowledge Base on Helium Ion Therapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiobiology

Background:

• Intensity-modulated radiation therapy (IMRT) using photons can cause significant normal tissue toxicity, leading to treatment interruptions and reduced quality of life.
• Charged particle therapies like protons and carbon ions offer potential advantages over IMRT but have physical limitations affecting dose precision.
• Helium ions present intermediate biophysical properties, suggesting improved precision and biological effectiveness compared to protons and photons.

Purpose of the Study:

• To review the current knowledge on the biophysical effects of helium ion radiotherapy (HeRT).
• To evaluate the potential of HeRT as an advanced cancer treatment modality.
• To highlight the need for systematic studies on HeRT due to its scarcity in current literature.

Main Methods:

• Literature review of existing studies on helium ion radiotherapy.
• Analysis of biophysical characteristics of helium ions in comparison to photons, protons, and carbon ions.
• Examination of HeRT effects on cellular level: relative biological effectiveness (RBE), gene mutation, DNA damage and repair, cell cycling, cell death, and radiosensitization.

Main Results:

• Helium ions possess biophysical properties intermediate between protons and carbon ions, potentially offering enhanced dose deposition and reduced normal tissue irradiation.
• Early data suggests HeRT may have a distinct relative biological effectiveness (RBE) profile compared to photons.
• Explorations into ultra-high dose rate HeRT are emerging, indicating potential for novel treatment delivery strategies.

Conclusions:

• Helium ion radiotherapy (HeRT) shows promise for improving cancer treatment by potentially enhancing tumor control and minimizing toxicity to surrounding healthy tissues.
• Further systematic investigation into the biophysical effects and clinical efficacy of HeRT is crucial for its advancement.
• Helium ions represent a potentially valuable addition to the landscape of particle therapy, warranting continued research and development.