On the robustness of multilateration of ionoacoustic signals for localization of the Bragg peak at pre-clinical proton beam energies in water.

The energy deposited in a medium by a pulsed proton beam results in the emission of thermoacoustic waves, also called ionoacoustics (IA). The proton beam stopping position (Bragg peak) can be retrieved from a time-of-flight analysis (ToF) of IA signals acquired at different sensor locations (multilateration). This work aimed to assess the robustness of multilateration methods in proton beams at pre-clinical energies for the development of a small animal irradiator.

Proton beam range verification by means of ionoacoustic measurements at clinically relevant doses using a correlation-based evaluation.

Purpose: The Bragg peak located at the end of the ion beam range is one of the main advantages of ion beam therapy compared to X-Ray radiotherapy. However, verifying the exact position of the Bragg peak within the patient online is a major challenge. The goal of this work was to achieve submillimeter proton beam range verification for pulsed proton beams of an energy of up to 220 MeV using ionoacoustics for a clinically relevant dose deposition of typically 2 Gy per fraction by i) using optimal proton beam characteristics for ionoacoustic signal generation and ii) improved signal detection by correlating the signal with simulated filter templates.

Development and pre-clinical test of a phosphorous-32 containing polyetheretherketone foil aiming at urethral stricture prevention by low-dose-rate brachytherapy.

Purpose: Primary or recurrent urethral stenoses are common clinical problems. The aim of this feasibility study was development and application test of a novel radioactive catheter for potential use in low-dose-rate (LDR) brachytherapy to prevent urethral stenosis.

Material And Methods: A beta radiation emitting phosphorous-32 (P)-foil was developed and integrated in indwelling catheter, which is usually inserted after surgical intervention in the urethra.

Experimental demonstration of accurate Bragg peak localization with ionoacoustic tandem phase detection (iTPD).

Accurate knowledge of the exact stopping location of ions inside the patient would allow full exploitation of their ballistic properties for patient treatment. The localized energy deposition of a pulsed particle beam induces a rapid temperature increase of the irradiated volume and leads to the emission of ionoacoustic (IA) waves. Detecting the time-of-flight () of the IA wave allows inferring information on the Bragg peak location and can henceforth be used forrange verification.

Investigating the accuracy of co-registered ionoacoustic and ultrasound images in pulsed proton beams.

The sharp spatial and temporal dose gradients of pulsed ion beams result in an acoustic emission (ionoacoustics), which can be used to reconstruct the dose distribution from measurements at different positions. The accuracy of range verification from ionoacoustic images measured with an ultrasound linear array configuration is investigated both theoretically and experimentally for monoenergetic proton beams at energies relevant for pre-clinical studies (20 and 22 MeV). The influence of the linear sensor array arrangement (length up to 4 cm and number of elements from 5 to 200) and medium properties on the range estimation accuracy are assessed using time-reversal reconstruction.