Modified X-ray tube for high dose rate FLASH radiotherapy research

Area of Science:

• Medical Physics
• Radiation Oncology
• Biophysics

Background:

• Conventional radiotherapy (CONV-RT) faces limitations in widespread adoption for FLASH radiotherapy (FLASH-RT) due to reliance on expensive particle accelerators.
• Kilovoltage (kV) X-ray tubes present a more accessible and cost-effective alternative for FLASH-RT research and application.

Purpose of the Study:

• To investigate the feasibility of modifying rotating anode X-ray tubes to achieve ultra-high dose rates for FLASH radiotherapy research.
• To enhance dose rate capabilities and expand the beam exit port of kV X-ray tubes for improved experimental setups.

Main Methods:

• A high-capacity X-ray tube was modified to shorten the source-to-surface distance (SSD) and enlarge the beam exit port.
• Dose rate measurements were conducted using solid water phantoms and radiochromic film to evaluate performance before and after modification.

Main Results:

• The modified X-ray tube achieved a maximum surface dose rate of 200 Gy/s at a 29.5 mm SSD, a 1.6-fold increase.
• The expanded beam exit port measured 127 mm x 96 mm, facilitating larger sample placement.
• FLASH dose rates exceeding 40 Gy/s were achieved at depths up to 25 mm in solid water.

Conclusions:

• Housing modifications to rotating anode X-ray tubes effectively enhance ultra-high dose rate delivery for FLASH experiments.
• This adapted kV X-ray tube configuration provides an accessible platform for laboratory-based FLASH radiotherapy research, despite challenges like dose uniformity and tube lifespan.