Development of a micro-computed tomography-based image-guided conformal radiotherapy system for small animals

Area of Science:

• Preclinical research
• Medical physics
• Radiotherapy technology

Background:

• Micro-computed tomography (microCT) scanners are valuable for small-animal imaging.
• Integrating radiotherapy functionality into microCT offers potential for advanced preclinical studies.
• Accurate image guidance is crucial for effective radiation delivery in small animal models.

Purpose of the Study:

• To detail the physical modifications for adding radiotherapy to a microCT scanner.
• To assess the accuracy of the integrated microCT-radiotherapy system.
• To demonstrate the system's application in irradiating mouse lung tumors.

Main Methods:

• A GE eXplore RS120 microCT scanner was modified with a translation stage and collimator.
• Quality assurance protocols were developed for positioning and aperture accuracy.
• Image-guided radiotherapy was tested on phantoms and mice with MYC-induced lung tumors.

Main Results:

• Translation stage positioning error was <0.05 mm; collimator aperture error was <0.1 mm.
• Image-guided treatment achieved target localization accuracy within 0.1 mm.
• Gamma-H2AX foci confirmed radiation damage in mouse lung tumors.

Conclusions:

• Integrating radiotherapy into microCT is effective for preclinical image-guided radiation.
• This approach enables conformal radiotherapy in small animals using existing technology.
• The system facilitates precise radiation delivery for preclinical tumor studies.