X‐ray‐induced acoustic computed tomography for guiding prone stereotactic partial breast irradiation: a simulation study

Abstract

The aim of this study is to investigate the feasibility of x-ray-induced acoustic computed tomography (XACT) as an image guidance tool for tracking x-ray beam location and monitoring radiation dose delivered to the patient during stereotactic partial breast irradiation (SPBI). Methods: An in-house simulation workflow was developed to assess the ability of XACT to act as an in vivo dosimetry tool for SPBI. To evaluate this simulation workflow, a three-dimensional (3D) digital breast phantom was created by a series of two-dimensional (2D) breast CT slices from a patient. Three different tissue types (skin, adipose tissue, and glandular tissue) were segmented and the postlumpectomy seroma was simulated inside the digital breast phantom. A treatment plan was made with three beam angles to deliver radiation dose to the seroma in breast to simulate SPBI. The three beam angles for 2D simulations were 17°, 90°and 159°(couch angles were 0 degrees) while the angles were 90 degrees (couch angles were 0°, 27°, 90°) in 3D simulation. A multi-step simulation platform capable of modelling XACT was developed. First, the dose distribution was converted to an initial pressure distribution. The propagation of this pressure disturbance in the form of induced acoustic waves was then modeled using the k-wave MATLAB toolbox. The waves were then detected by a hemispherical-shaped ultrasound transducer array (6320 transducer locations distributed on the surface of the breast). Finally, the time-varying pressure signals detected at each transducer location were used to reconstruct an image of the initial pressure distribution using a 3D time-reversal reconstruction algorithm. Finally, the reconstructed XACT images of the radiation beams were overlaid onto the structure breast CT. Results: It was found that XACT was able to reconstruct the dose distribution of SPBI in 3D. In the reconstructed 3D volumetric dose distribution, the average doses in the GTV (Gross Target Volume) and PTV (Planning Target Volume) were 86.15% and 80.89%, respectively. When compared to the treatment plan, the XACT reconstructed dose distribution in the GTV and PTV had a RMSE (root mean square error) of 2.408 % and 2.299 % over all pixels. The 3D breast XACT imaging reconstruction with time-reversal reconstruction algorithm can be finished within several minutes. Conclusions: This work explores the feasibility of using the novel imaging modality of XACT as an in vivo dosimeter for SPBI radiotherapy. It shows that XACT imaging can provide the x-ray beam location and dose information in deep tissue during the treatment in real time in 3D. This study lays the groundwork for a variety of future studies related to the use of XACT as a dosimeter at different cancer sites.

4D in vivo dosimetry for a FLASH electron beam using radiation-induced acoustic imaging

“…While RAI has been predominantly validated in conventional radiotherapy (Xiang et al 2012, Sampaio et al 2015, Kim et al 2017, Lei et al 2018, Zheng et al 2020, Zhang et al 2023, confirming its linearity in the FLASH regime is crucial. For the first time, we have extended RAI imaging to FLASH-RT, testing doses up to 5 Gy per pulse, which is 5000 times stronger than the doses typically used in conventional radiotherapy.…”

“…Cerenkov radiation provides a viable option for surface in vivo dosimetry (Glaser et al 2013, Jarvis et al 2014, it falls short in monitoring deep-seated tumors. Recent advancements in radiation-induced acoustic imaging (RAI) have shown promise for in vivo dosimetry in treating tumors deep inside the patient (Ahmad et al 2015, Patch et al 2016, Kim et al 2017, Lei et al 2018, Hickling et al 2018b, Zheng et al 2020, Zhang et al 2023.…”

Model-Based X-Ray-Induced Acoustic Computed Tomography

“…However, due to the high computational time associated with the ITR algorithm, it has limited clinical applicability. In a recent numerical study [28], the potential of XACT for tracking the X-ray beam and in vivo dosimetry during stereotactic partial breast irradiation [29] was examined. Wang et al carried out simulations to demonstrate the feasibility of using a transperineal (planar) ultrasound transducer array for XACT imaging to monitor prostate radiotherapy [30].…”

Review of in vivo optical molecular imaging and sensing from x-ray excitation

“…This field is called x-ray acoustic imaging or radioacoustics. [19][20][21][22][23] These modes of sensing the x-ray interaction are illustrated in Fig. 2, with the incident and detection scheme on top and the physical mode of contrast illustrated on bottom.…”