Molecular Imaging to Plan Radiotherapy and Evaluate Its Efficacy

Area of Science:

• Molecular imaging applications in radiation oncology.
• Quantitative imaging for radiotherapy planning and response assessment.

Background:

• Molecular imaging is integral to radiation oncology, demanding higher reproducibility and image quality than diagnostic imaging.
• Challenges include patient preparation, technologist training, protocol design, scanner technology, software algorithms, and data analysis.

Purpose of the Study:

• To explore the role of molecular imaging in improving target definition, reducing interobserver variability, and enabling biologically conformal radiotherapy.
• To assess the utility of molecular imaging in predicting and prognosticating treatment response.
• To identify barriers and facilitators for the widespread adoption of molecular imaging in radiation oncology.

Main Methods:

• Review of current molecular imaging techniques and their applications in radiotherapy.
• Discussion of challenges in target volume delineation, dose painting, and response assessment.
• Analysis of factors influencing the adoption of molecular imaging, including clinical evidence, training, and interdisciplinary collaboration.

Main Results:

• Molecular imaging can significantly reduce interobserver variability in target delineation and improve conformity between target volumes and tumor boundaries.
• Biologically conformal radiotherapy based on tumor heterogeneity is under investigation.
• Molecular imaging serves as a predictive and prognostic tool for early and late treatment response assessment, though radiation-induced inflammation requires careful interpretation.

Conclusions:

• Molecular imaging is vital in radiation oncology but requires further validation, standardized protocols, and robust clinical evidence for broader implementation.
• (18)F-FDG PET/CT is the primary modality, with limitations in tracer availability and reimbursement hindering others.
• Enhanced training for radiation oncology personnel and strong interdisciplinary collaboration are essential for the optimal and safe use of quantitative molecular imaging.