Breathing-synchronized delivery: a potential four-dimensional tomotherapy treatment technique.

Area of Science:

• Radiation Oncology
• Medical Physics
• Image-Guided Therapy

Background:

• Motion management is critical in radiation therapy to accurately deliver doses to tumors.
• Conventional techniques often struggle to compensate for respiratory motion, potentially leading to under- or over-dosing.
• Improved patient tolerance and treatment efficacy are key goals in modern radiotherapy.

Purpose of the Study:

• To present a novel four-dimensional (4D) tomotherapy technique.
• To enhance motion control during radiation delivery.
• To improve patient tolerance in tomotherapy treatments.

Main Methods:

• Acquired computed tomographic (CT) images at 10 breathing phases for treatment planning.
• Utilized the full exhalation phase as the planning reference, omitting breathing motion margins.
• Developed a laser/spirometer system for breathing monitoring and incorporated motion into inverse treatment planning.

Main Results:

• 4D tomotherapy achieved dose distributions on moving targets comparable to conventional methods on static targets.
• Breathing motion was effectively compensated through motion-incorporated, breathing-synchronized delivery planning.
• The technique maintained a near 100% duty cycle without increasing treatment duration.

Conclusions:

• Breathing-synchronized delivery represents a feasible 4D tomotherapy technique.
• This method offers improved control over tumor motion during treatment.
• Enhanced motion control contributes to better patient tolerance and potentially improved treatment outcomes.