[Gated Radiotherapy]

Area of Science:

• Oncology
• Medical Physics
• Radiotherapy Technology

Background:

• Advances in diagnostic imaging enable detection of small, curable tumors.
• Tumor movement (1-3 cm) in respiratory and bowel organs complicates high-dose radiotherapy delivery.
• Existing respiratory-gating techniques have known advantages and disadvantages.

Purpose of the Study:

• To review current respiratory-gating and real-time tumor-tracking radiotherapy techniques.
• To highlight the challenges and potential solutions for precise tumor targeting during irradiation.
• To identify areas requiring further research for improved radiotherapy accuracy.

Main Methods:

• Review of respiratory-gating techniques used with medical linear accelerators and particle therapy.
• Evaluation of real-time tumor-tracking radiotherapy using fluoroscopic X-rays, internal gold markers, and pattern recognition.
• Consideration of the active breath control method as a cost-effective alternative.

Main Results:

• Both respiratory-gating and real-time tracking methods have demonstrated feasibility.
• The limitations and benefits of each technique have been identified.
• Active breath control presents a promising cost-effective approach for precise treatment without gating.

Conclusions:

• Further investigation is needed to correlate external abdominal wall movement with internal tumor motion in respiratory-gating radiotherapy.
• Additional research is required to establish the relationship between internal markers and target volume in real-time tracking radiotherapy.
• Optimizing these techniques is crucial for delivering precise, high-dose irradiation to challenging tumor sites.