Bioluminescence Tomography-Guided Radiation Therapy for Preclinical Research

Area of Science:

• Preclinical Radiation Oncology
• Biomedical Imaging
• Medical Physics

Background:

• Soft tissue target localization is a significant challenge in preclinical radiation research using cone beam computed tomography (CBCT).
• Existing methods lack the precision required for targeting small or nonpalpable soft tissues in animal models.
• Developing advanced imaging techniques is crucial for accurate image-guided radiation therapy (IGRT).

Purpose of the Study:

• To develop and validate an online bioluminescence tomography (BLT) system for precise soft tissue target localization.
• To integrate the BLT system with a small-animal radiation research platform (SARRP) for real-time guidance.
• To demonstrate the efficacy of BLT-guided radiation therapy and assess its targeting accuracy.

Main Methods:

• An online BLT system was designed to dock with the SARRP, utilizing a 3-mirror system and a charge-coupled device (CCD) camera for bioluminescence detection.
• Multispectral BLT with an optimized reconstruction algorithm (incomplete variables truncated conjugate gradient method with permissible region shrinking) was employed.
• Targeting accuracy was validated using a light source in phantoms and mouse carcasses, comparing BLT-guided delivery with CBCT-guided delivery.

Main Results:

• The online BLT system achieved an average targeting accuracy of 1 mm for localizing the center of mass (CoM) of a light source, comparable to CBCT.
• Film analysis confirmed consistency between BLT- and CBCT-guided irradiation accuracy.
• In vivo experiments demonstrated the BLT system's capability for localizing multiple targets and tumors.

Conclusions:

• The integrated online BLT/CBCT/SARRP system offers an effective solution for soft tissue targeting in preclinical radiation research.
• This system is particularly beneficial for small, nonpalpable, or orthotopic tumor models.
• BLT significantly enhances the precision of image-guided radiation therapy in small animal studies.