Different styles of image-guided radiotherapy

Area of Science:

• Radiation Oncology
• Medical Imaging
• Radiotherapy Physics

Background:

• Geometric uncertainties in radiotherapy necessitate safety margins, often overlapping organs at risk and limiting dose escalation.
• Image-guided radiotherapy (IGRT) aims to improve accuracy by imaging tumors and critical structures immediately before treatment delivery.

Purpose of the Study:

• To review the prerequisites, methods, and clinical applications of image-guided radiotherapy.
• To discuss correction strategies and the impact of imaging dose on overall treatment.
• To highlight IGRT as a clinical reality and emphasize the need for protocol optimization.

Main Methods:

• Review of planning, image acquisition, and processing requirements for IGRT.
• Discussion of correction techniques including table shifts, rotation, and machine parameter adaptation.
• Analysis of online, offline, and intrafraction correction strategies.

Main Results:

• High-quality imaging and automatic registration enable new applications like hypofractionated treatments for brain metastases and solitary lung tumors.
• Kilovoltage cone-beam computed tomography (kV-CBCT) guidance offers a net positive impact on integral dose, with margin reduction benefits outweighing imaging dose.
• IGRT significantly improves treatment precision and safety.

Conclusions:

• Image-guided radiotherapy is a well-established clinical practice.
• Further research should focus on developing optimal clinical protocols for IGRT.
• IGRT facilitates safer and more effective cancer treatments through enhanced accuracy and reduced margins.