Experimental tests of proton beam localization

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Medicine

Background:

• Heavy charged-particle therapy, including proton therapy, offers precise dose delivery but is sensitive to tissue density variations.
• Accurate localization of the therapeutic beam's range is crucial for maximizing efficacy and minimizing off-target radiation exposure.
• Current methods for beam range verification can be limited in real-time, in vivo accuracy.

Purpose of the Study:

• To investigate the feasibility of using in vivo positron emission detection for localizing proton therapy beams.
• To assess the potential of activating the short-lived isotope oxygen-15 (15O) for real-time beam range verification.
• To determine if this technique is applicable to other heavy charged-particle beams.

Main Methods:

• Calculations were performed to predict the feasibility of detecting positron emissions from activated 15O.
• Preliminary tests were conducted using a large field-of-view positron camera.
• The method involved delivering a proton therapy beam and monitoring for 15O decay signals.

Main Results:

• Calculations indicated that in vivo 15O activation could enable proton beam localization with adequate detected-event density and dose.
• Preliminary tests demonstrated successful beam localization at depth with a typical dose of 15 rad.
• The technique showed promise for real-time, in vivo monitoring of beam range.

Conclusions:

• In vivo positron emission detection via 15O activation is a viable method for localizing proton therapy beams.
• This technique offers improved accuracy for determining the maximum depth of dose in heavy charged-particle therapy.
• The method is potentially applicable to other heavy charged-particle modalities like negative pions and heavy ions.