A surrogate urethra for real-time planning of high-dose-rate prostate brachytherapy

Halperin, Heather; Hilts, Michelle; Crook, Juanita; Batchelar, Deidre; Tisseverasinghe, Steven; Tétreault-Laflamme, Audrey; Bachand, François

doi:10.1016/j.brachy.2019.05.009

Cited by 3 publications

(3 citation statements)

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“…Although the “urethra with a Foley catheter” is referred to be used as the ground truth in the GEC/ESTRO-EAU recommendations [22], the present study suggested that the “urethra with a Foley catheter” is not a suitable “surrogate urethra” in general. Recently, population-based prediction methods of the prostate urethral position are published using CT image set or ultrasound image set [30, 31]. Acosta et al proposed a sophisticated method but used the urethra with a Foley catheter as the ground truth in their analysis [30].…”

Section: Discussionmentioning

confidence: 99%

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The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

et al. 2019

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PurposeTo determine the best method to contour the planning organ at risk volume (PRV) for the urethra, this study aimed to investigate the displacement of a Foley catheter in the urethra with a soft and thin guide-wire.MethodsFor each patient, the study used two sets of computed tomography (CT) images for radiation treatment planning (RT-CT): (1) set with a Foley urethral catheter (4.0 mm diameter) plus a guide-wire (0.46 mm diameter) in the first RT-CT and (2) set with a guide-wire alone in the second CT recorded 2 min after the first RT-CT. Using three fiducial markers in the prostate for image fusion, the displacement between the catheter and the guide-wire in the prostatic urethra was calculated. In 155 consecutive patients treated between 2011 and 2017, 5531 slices of RT-CT were evaluated.ResultsAssuming that ≥3.0 mm of difference between the catheter and the guide-wire position was a significant displacement, the urethra with the catheter was displaced significantly from the urethra with the guide-wire alone in > 20% of the RT-CT slices in 23.2% (36/155) of the patients. The number of patients who showed ≥3.0 mm anterior displacement with the catheter in ≥20% RT-CT slices was significantly larger at the superior segment (38/155) than at the middle (14/155) and inferior segments (18/155) of the prostatic urethra (p < 0.0167).ConclusionsThe urethral position with a Foley catheter is different from the urethral position with a thin and soft guide-wire in a significant proportion of the patients. This should be taken into account for the PRV of the urethra to ensure precise radiotherapy such as in urethra-sparing radiotherapy.

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Section: Discussionmentioning

confidence: 99%

“…Acosta et al proposed a sophisticated method but used the urethra with a Foley catheter as the ground truth in their analysis [30]. Halperin et al suggested the risk of dislocation of the urethra with the catheter in brachytherapy using ultrasound images, but it is difficult to use ultrasound image for external beam USRT [31].…”

Section: Discussionmentioning

confidence: 99%

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

et al. 2019

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“…As discussed before, the urethra structure presents significant discrepancies due to the different patient geometry voxel size used for MC calculations and DL model training. Despite the common representation of the urethra as a standard 6 mm diameter circle, the diameter can vary (Halperin et al 2019). In certain slices of resampled patient geometries, the structure was identified with a diameter of only four voxels.…”

Section: Combined Prostate Patientsmentioning

confidence: 99%

Fast D _M,M calculation in LDR brachytherapy using deep learning methods

2023

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\textbf{Objective:} The Monte Carlo (MC) method provides a complete solution to the tissue heterogeneity effects in low-energy low-dose rate (LDR) brachytherapy. However, long computation times limit the clinical implementation of MC-based treatment planning solutions. This work aims to apply deep learning (DL) methods, specifically a model trained with MC simulations, to predict accurate dose to medium in medium (D\textsubscript{M,M}) distributions in LDR prostate brachytherapy.\\\textbf{Approach:} To train the DL model, 2369 single-seed configurations, corresponding to 44 prostate patient plans, were used. These patients underwent LDR brachytherapy treatments in which $^{125}$I SelectSeed sources were implanted. For each seed configuration, the patient geometry, the MC dose volume and the single-seed plan volume were used to train a 3D Unet convolutional neural network. Previous knowledge was included in the network as an r\textsuperscript{2} kernel related to the first-order dose dependency in brachytherapy. MC and DL dose distributions were compared through the dose maps, isodose lines, and dose-volume histograms. Features enclosed in the model were visualized.\\\textbf{Main results:} Model features started from the symmetrical kernel and finalized with an anisotropic representation that considered the patient organs and their interfaces, the source position, and the low- and high-dose regions. For a full prostate patient, small differences were seen below the 20\% isodose line. When comparing DL-based and MC-based calculations, the predicted CTV D\textsubscript{90} metric had an average difference of -0.1\%. Average differences for OARs were -1.3\%, 0.07\%, and 4.9\% for the rectum D\textsubscript{2cc}, the bladder D\textsubscript{2cc}, and the urethra D\textsubscript{0.1cc}. The model took 1.8 ms to predict a complete 3D D\textsubscript{M,M} volume (1.18 M voxels).\\\textbf{Significance:} The proposed DL model stands for a simple and fast engine which includes prior physics knowledge of the problem. Such an engine considers the anisotropy of a brachytherapy source and the patient tissue composition.

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A dosimetric evaluation of a single urethral constraint for high-dose-rate prostate brachytherapy

Phillips

DeMarco

et al. 2020

Brachytherapy

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A surrogate urethra for real-time planning of high-dose-rate prostate brachytherapy

Cited by 3 publications

References 29 publications

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

Fast D _M,M calculation in LDR brachytherapy using deep learning methods

A dosimetric evaluation of a single urethral constraint for high-dose-rate prostate brachytherapy

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A surrogate urethra for real-time planning of high-dose-rate prostate brachytherapy

Cited by 3 publications

References 29 publications

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy

Fast D M,M calculation in LDR brachytherapy using deep learning methods

A dosimetric evaluation of a single urethral constraint for high-dose-rate prostate brachytherapy

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Fast D _M,M calculation in LDR brachytherapy using deep learning methods