Single-Pulse X-ray Acoustic Computed Tomographic Imaging for Precision Radiation Therapy.

Area of Science:

• Medical Physics
• Biomedical Imaging
• Radiation Oncology

Background:

• High-precision radiation therapy requires accurate dose verification.
• Current methods rely on phantom simulations, lacking real-time, in-tumor dose monitoring.
• X-ray-induced acoustic computed tomography (XACT) shows promise for imaging radiation dose within tumors.

Purpose of the Study:

• To demonstrate the feasibility of single-pulse XACT for real-time radiation dose imaging.
• To overcome the limitations of previous XACT systems requiring extensive signal averaging.
• To achieve sub-mGy sensitivity from a single x-ray pulse.

Main Methods:

• Utilized an acoustic transducer immersed in a homogeneous medium to detect radiation-induced pressure waves.
• Employed tomographic reconstruction from signals acquired at various angles.
• Enhanced signal-to-noise ratio (SNR) using two-stage amplification and bandpass filtering.

Main Results:

• Achieved a satisfactory SNR in single-pulse mode, meeting the Rose criterion.
• Successfully reconstructed 2D dose images from homogeneous media using single-pulse data.
• Demonstrated sub-mGy sensitivity with a single 4 µs x-ray pulse from a clinical linear accelerator.

Conclusions:

• Single-pulse XACT imaging overcomes SNR limitations and the need for signal averaging.
• This technique offers significant potential for personalized, real-time dose monitoring during radiation therapy.
• Enables precise tracking of radiation dose for each individual pulse delivered to the patient.