Benchmarking Doses to Inform Optimization of Radiological Protection for Verification Imaging in Radiation Therapy.

Area of Science:

• Medical Physics
• Radiotherapy
• Radiation Protection

Background:

• Accurate targeting in external beam radiation therapy relies on frequent patient imaging.
• Verification imaging, such as Cone Beam Computed Tomography (CBCT), can expose healthy tissues to additional radiation.
• Repeated imaging doses, though lower than therapeutic doses, pose a risk of secondary cancers, especially in younger patients.

Purpose of the Study:

• To review methods for managing patient imaging doses in diagnostic radiology.
• To explore the application of these methods to optimize radiological protection in image-guided radiotherapy (IGRT).
• To identify suitable dose quantities for surveying and benchmarking imaging doses in radiotherapy.

Main Methods:

• Review of dose management strategies in diagnostic radiology.
• Identification of relevant dose indices like Cone Beam Dose Index (CBDI) and CTDIw for radiotherapy imaging.
• Discussion of actions needed for dose optimization and establishing radiotherapy-specific dose reference levels.

Main Results:

• Radiotherapy departments often use default imaging protocols with limited optimization, unlike diagnostic radiology.
• Information on CBCT imaging doses is frequently unavailable, hindering dose management.
• Diagnostic radiology practices offer a model for surveying and benchmarking patient imaging doses in IGRT.

Conclusions:

• Establishing radiotherapy-specific dose reference levels is crucial for optimizing patient doses.
• Implementing dose optimization can balance image quality with patient safety.
• Systematic dose reduction through benchmarking can improve the safety and effectiveness of IGRT.