Comparison of the Dosimetric Influence of Applicator Displacement on 2D and 3D Brachytherapy for Cervical Cancer Treatment

Wu, Ailin; Tang, Du; Wu, Aiqing; Liu, Yunqin; Liu, Qian; Zhu, Lei

doi:10.1177/15330338211041201

Cited by 6 publications

(5 citation statements)

References 29 publications

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“…There is little published data assessing the dosimetric impact of brachytherapy applicator displacements during image-guided adaptive brachytherapy for cervical cancer [17,18,32]. Our findings demonstrate the clinical significance of even small shifts in IC or IC/IS applicator position, and closely reflect previous studies evaluating IC applicators alone.…”

Section: Discussionsupporting

confidence: 82%

“…In contrast, we found statistically significant differences at displacements of 5 mm or greater, with an approximate 23% difference in the dose to the HR-CTV D 90% at 10 mm of displacement. A similar study performed by Wu et al modeled displacements for tandem and ovoid applicators, and found reductions in the dose to the HR-CTV D 90% of approximately 15% at 10 mm inferior displacement [17]. The cause for this discrepancy in results between the two studies is not clear, though possibilities would include institutional differences in planning practices, inter-provider differences in contouring technique, and difference in brachytherapy applicator geometry.…”

Section: Discussionmentioning

confidence: 94%

“…Previous single institution modeling studies utilizing intracavitary (IC) applicators have demonstrated that small displacements in applicator positioning may lead to substantial alterations in dosimetry [17,18]. However, these studies included relatively small numbers of patients and the data has not been corroborated.…”

Section: Purposementioning

confidence: 99%

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Dosimetric impact of applicator displacement on three-dimensional image-guided high-dose-rate brachytherapy treatments for cervical cancer

Jayarathna,

Hoang,

Badkul

et al. 2023

jcb

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Purpose: To determine the dosimetric impact of brachytherapy applicator displacement during intracavitary (IC) and combined intracavitary/interstitial (IC/IS) high-dose-rate brachytherapy in the treatment of cervical cancer.Material and methods: Data from 27 consecutively treated patients undergoing IC or IC/IS high-dose-rate brachytherapy with tandem and ovoid-based applicators at a single academic medical center were analyzed. Virtual applicator displacements (a single shift of whole applicator with tandem/ovoid/associated needles) of 0 (clinical position), 2, 5, 7, and 10 mm in the inferior direction were modeled on treatment planning CT or MRI scans, with maintaining the same dwell times. Radiation dose to target volumes (D 90 of high-risk clinical target volume) and organs at risk (OARs) (D 0.1cc , D 1cc , and D 2cc of bladder, rectum, and sigmoid) were calculated for each virtual applicator shift, and significance of displacements was assessed using general linear model and Kruskal-Wallis test.Results: Mean dose to high-risk clinical target volume (HR-CTV) D 90 was 95.7%, 88.9%, 84.6%, and 77.1% of the prescribed dose in clinical position with displacements of 2, 5, 7, and 10 mm, respectively. Rectal D 2cc significantly increased by 28% and 44% at displacement of 7 mm and 10 mm, respectively. IC/IS cases showed relatively greater dosimetric differences than IC cases, with HR-CTV D 90 doses of 94.4%, 85.8%, 80.4%, and 72.4% at virtual displacements of 2, 5, 7, and 10 mm, respectively.Conclusions: Applicator displacements of 5 mm or greater result in statistically significant and clinically meaningful decreases in radiation dose to HR-CTV during 3-dimensional high-dose-rate brachytherapy treatment planning, with corresponding increase in radiation dose to the rectum. IC/IS applicator displacements lead to relatively greater differences than those of IC applicators.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 94%

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Dosimetric impact of applicator displacement on three-dimensional image-guided high-dose-rate brachytherapy treatments for cervical cancer

Jayarathna,

Hoang,

Badkul

et al. 2023

jcb

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“…The accuracy of applicators reconstruction has significant impact on dosimetric results of IGBT treatment plan because of steep dose gradients [9][10][11]. In general, applicators reconstruction are mostly performed manually by physicists.…”

Section: Purposementioning

confidence: 99%

Automatic reconstruction of interstitial needles using CT images in post-operative cervical cancer brachytherapy based on deep learning

Xie¹,

Wang²,

Chen³

et al. 2023

jcb

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The purpose of this study was to investigate the precision of deep learning (DL)-based auto-reconstruction in localizing interstitial needles in post-operative cervical cancer brachytherapy (BT) using three-dimensional (3D) computed tomography (CT) images.Material and methods: A convolutional neural network (CNN) was developed and presented for automatic reconstruction of interstitial needles. Data of 70 post-operative cervical cancer patients who received CT-based BT were used to train and test this DL model. All patients were treated with three metallic needles. Dice similarity coefficient (DSC), 95% Hausdorff distance (95% HD), and Jaccard coefficient (JC) were applied to evaluate the geometric accuracy of auto-reconstruction for each needle. Dose-volume indexes (DVI) between manual and automatic methods were used to analyze the dosimetric difference. Correlation between geometric metrics and dosimetric difference was evaluated using Spearman correlation analysis. Results:The mean DSC values of DL-based model were 0.88, 0.89, and 0.90 for three metallic needles. Wilcoxon signed-rank test indicated no significant dosimetric differences in all BT planning structures between manual and automatic reconstruction methods (p > 0.05). Spearman correlation analysis demonstrated weak link between geometric metrics and dosimetry differences.Conclusions: DL-based reconstruction method can be used to precisely localize the interstitial needles in 3D-CT images. The proposed automatic approach could improve the consistency of treatment planning for post-operative cervical cancer brachytherapy.

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“…Since cumbersome x-ray/CT/MR machines have not been widely installed in the BT treatment room, patient transfers between the imaging room and the treatment room are inevitable, which usually not only increases patient suffering but also causes organ variations and applicator displacement. During scanning, planning, and treatment, this inconsistency in the patients’ anatomy induces a large dose delivery error since the dose is sharply decreased ( 11 ). Due to its advantages, including low cost, volume imaging, and simple integration, cone-beam CT (CBCT) is promising for resolving all the above adverse factors.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a scatter-corrected CBCT image-guided method for cervical cancer brachytherapy

Cui²,

Jiang³

et al. 2022

Front. Oncol.

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Background and purposeMultiple patient transfers have a nonnegligible impact on the accuracy of dose delivery for cervical cancer brachytherapy. We consider using on-site cone-beam CT (CBCT) to resolve this problem. However, CBCT clinical applications are limited due to inadequate image quality. This paper implements a scatter correction method using planning CT (pCT) prior to obtaining high-quality CBCT images and evaluates the dose calculation accuracy of CBCT-guided brachytherapy for cervical cancer.Materials and methodsThe CBCT of a self-developed female pelvis phantom and five patients was first corrected using empirical uniform scatter correction in the projection domain and further corrected in the image domain. In both phantom and patient studies, the CBCT image quality before and after scatter correction was evaluated with registered pCT (rCT). Model-based dose calculation was performed using the commercial package Acuros®BV. The dose distributions of rCT-based plans and corrected CBCT-based plans in the phantom and patients were compared using 3D local gamma analysis. A statistical analysis of the differences in dosimetric parameters of five patients was also performed.ResultsIn both phantom and patient studies, the HU error of selected ROIs was reduced to less than 15 HU. Using the dose distribution of the rCT-based plan as the baseline, the γ pass rate (2%, 2 mm) of the corrected CBCT-based plan in phantom and patients all exceeded 98% and 93%, respectively, with the threshold dose set to 3, 6, 9, and 12 Gy. The average percentage deviation (APD) of D90 of HRCTV and D2cc of OARs was less than 1% between rCT-based and corrected CBCT-based plans.ConclusionScatter correction using a pCT prior can effectively improve the CBCT image quality and CBCT-based cervical brachytherapy dose calculation accuracy, indicating promising prospects in both simplified brachytherapy processes and accurate brachytherapy dose delivery.

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Comparison of the Dosimetric Influence of Applicator Displacement on 2D and 3D Brachytherapy for Cervical Cancer Treatment

Cited by 6 publications

References 29 publications

Dosimetric impact of applicator displacement on three-dimensional image-guided high-dose-rate brachytherapy treatments for cervical cancer

Dosimetric impact of applicator displacement on three-dimensional image-guided high-dose-rate brachytherapy treatments for cervical cancer

Automatic reconstruction of interstitial needles using CT images in post-operative cervical cancer brachytherapy based on deep learning

Development and validation of a scatter-corrected CBCT image-guided method for cervical cancer brachytherapy

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