The Development of Technology for Effective Respiratory-Gated Irradiation Using an Image-Guided Small Animal...

Area of Science:

• Preclinical Radiation Research
• Medical Physics
• Radiotherapy Technology

Background:

• Image-guided small animal irradiators improve preclinical radiotherapy studies.
• Current platforms lack respiratory gating, crucial for precise targeting of organs with significant motion (up to 5 mm in mice).
• Respiration-induced movement complicates accurate dose delivery in preclinical models.

Purpose of the Study:

• To design and implement a respiratory gating system for the Xstrahl Small Animal Radiation Research Platform (SARRP).
• To enable precise irradiation of targets affected by respiratory motion in small animal models.
• To enhance the accuracy and efficacy of preclinical radiotherapy studies.

Main Methods:

• Developed a new treatment head assembly including a fast X-ray shutter, motorized filter, ionization chamber, and targeting laser.
• Implemented a system to monitor breathing-related movement using diffuse reflectance light and a synchronous detector.
• Utilized thresholding and signal processing to isolate periods of minimal tissue movement for irradiation gating.

Main Results:

• Successfully demonstrated respiratory-gated X-ray irradiations in small animals.
• Validated the system by comparing X-ray imaging and dose profiles with and without gating.
• Showcased improved dose delivery accuracy during animal movement, particularly for thoracic and abdominal targets.

Conclusions:

• The developed respiratory gating system significantly improves dose delivery precision in small animal irradiation.
• This advancement provides a crucial tool for preclinical radiotherapy research, especially for targets within the chest and abdomen.
• The technology facilitates more accurate preclinical studies, better mimicking human radiotherapy conditions.