Evaluation of a mobile C‐arm cone‐beam <scp>CT</scp> in interstitial high‐dose‐rate prostate brachytherapy treatment planning

Djukelic, Mario; Waterhouse, David; Toh, Ryan; Tan, Hendrick; Rowshanfarzad, Pejman; Joseph, David; Ebert, Martin A.

doi:10.1002/jmrs.331

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…There are other imaging and localization techniques that do not involve invivo source tracking that are utilized clinically. These include the use of pre-treatment cone beam computed tomography (CBCT) to verify catheter positions prior to treatment, [19][20][21][22][23] real-time fluoroscopic imaging of HDR source using a flat panel detector, 24 the integration of an active magnetic resonance tracking (MRTR) system or magnetic resonance imaging (MRI) machine to local-ize HDR brachytherapy sources either before or during treatment 25,26 and the use of electromagnetic tracking (EMT) both in the pretreatment phase to assist in catheter placement and reconstruction, and online during treatment. [27][28][29] However, all systems seem to have a shortcoming, for in-vivo source tracking it is the lack of anatomical information and for imaging techniques, it is the lack of dwell time and position measurement.…”

Section: Introductionmentioning

confidence: 99%

Development of patient and catheter specific error thresholds for high dose rate prostate brachytherapy

Koprivec,

Belanger,

Beaulieu

et al. 2024

Medical Physics

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BackgroundIn‐vivo source tracking has been an active topic of research in the field of high‐dose rate brachytherapy in recent years to verify accuracy in treatment delivery. Although detection systems for source tracking are being developed, the allowable threshold of treatment error is still unknown and is likely patient‐specific due to anatomy and planning variation.PurposeThe purpose of this study was to determine patient and catheter‐specific shift error thresholds for in‐vivo source tracking during high‐dose‐rate prostate brachytherapy (HDRPBT).MethodsA module was developed in the previously described graphical processor unit multi‐criteria optimization (gMCO) algorithm. The module generates systematic catheter shift errors retrospectively into HDRPBT treatment plans, performed on 50 patients. The catheter shift model iterates through the number of catheters shifted in the plan (from 1 to all catheters), the direction of shift (superior, inferior, medial, lateral, cranial, and caudal), and the magnitude of catheter shift (1–6 mm). For each combination of these parameters, 200 error plans were generated, randomly selecting the catheters in the plan to shift. After shifts were applied, dose volume histogram (DVH) parameters were re‐calculated. Catheter shift thresholds were then derived based on plans where DVH parameters were clinically unacceptable (prostate V100 < 95%, urethra D0.1cc > 118%, and rectum Dmax > 80%). Catheter thresholds were also Pearson correlated to catheter robustness values.ResultsPatient‐specific thresholds varied between 1 to 6 mm for all organs, in all shift directions. Overall, patient‐specific thresholds typically decrease with an increasing number of catheters shifted. Anterior and inferior directions were less sensitive than other directions. Pearson's correlation test showed a strong correlation between catheter robustness and catheter thresholds for the rectum and urethra, with correlation values of –0.81 and –0.74, respectively (p < 0.01), but no correlation was found for the prostate.ConclusionsIt was possible to determine thresholds for each patient, with thresholds showing dependence on shift direction, and number of catheters shifted. Not every catheter combination is explorable, however, this study shows the feasibility to determine patient‐specific thresholds for clinical application. The correlation of patient‐specific thresholds with the equivalent robustness value indicated the need for robustness consideration during plan optimization and treatment planning.

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Section: Introductionmentioning

confidence: 99%

Development of patient and catheter specific error thresholds for high dose rate prostate brachytherapy

Koprivec,

Belanger,

Beaulieu

et al. 2024

Medical Physics

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“…These 3‐in‐1 systems are principally capable of covering a wide range of imaging tasks. For instance, broad applications have already been reported for head–neck surgery, 1 maxillofacial surgery, 5,6 dentistry, 7,8 and radiotherapy 9–12 . To ensure performance stability in clinical operation, conducting technical quality assurance (QA) is essential.…”

Section: Introductionmentioning

confidence: 99%

Quality assurance and long‐term stability of a novel 3‐in‐1 X‐ray system for brachytherapy

Karius

Szkitsak

Boronikolas

et al. 2022

J Applied Clin Med Phys

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Purpose: A novel, mobile 3-in-1 X-ray system featuring radiography, fluoroscopy, and cone-beam computed tomography (CBCT) has been launched for brachytherapy recently. Currently, there is no quality assurance (QA) procedure explicitly applicable to this system equipped with innovative technologies such as dynamic jaws and motorized lasers. We developed a dedicated QA procedure and, based on its performance for a duration of 6 months, provide an assessment of the device's stability over time. Methods: With the developed QA procedure, we assessed the system's planar and CBCT-imaging performance by investigating geometric accuracy, CTnumber stability, contrast-noise-ratio, uniformity, spatial resolution, low-contrast detectability, dynamic range, and X-ray exposure using dedicated phantoms. Furthermore, we evaluated geometric stability by using the flexmap-approach and investigated the device's laser-and jaw-positioning accuracy with an in-house test phantom. CBCT-and planar-imaging protocols for pelvis, breast, and abdomen imaging were examined. Results: Planar-and CBCT-imaging performances were widely stable with a geometric accuracy ≤1 mm, CT-number stability of up to 46 HU, and uniformity variations of up to 48 HU over time. For planar imaging, low-contrast detectability and dynamic range exceeded current recommendations. Although geometric stability was considered tolerable, partly substantial positioning inaccuracies of up to more than 120 mm and −13 mm were obtained for lasers and jaws, respectively. X-ray exposure showed small variations of ≤0.56 µGy and ≤0.76 mGy for planar-and CBCT-imaging, respectively. The conductance of the QA procedure allowed a smooth evaluation of the system's overall performance. Conclusion:We developed a QA workflow for a novel 3-in-1 X-ray system allowing to assess the device's imaging and hardware performance. The system showed in general a reasonable imaging performance and stability over time, whereas improvements regarding laser and jaw accuracy are strictly required.

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“…Recently, on-site CBCT has attracted increasing attention in adaptive BT ( 24 ). However, existing study results show that the current CBCT image quality is not adequate to meet the clinical requirements ( 24 – 26 ), and performance improvements of CBCT images are needed. Recall that cervical BT is always coupled with EBRT ( 3 ), and the prior information-based methods ( 27 , 28 ) are especially suitable in BT since high-quality EBRT-CT routinely obtained for treatment planning can be used as a prior.…”

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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Evaluation of a mobile C‐arm cone‐beam CT in interstitial high‐dose‐rate prostate brachytherapy treatment planning

Cited by 5 publications

References 11 publications

Development of patient and catheter specific error thresholds for high dose rate prostate brachytherapy

Development of patient and catheter specific error thresholds for high dose rate prostate brachytherapy

Quality assurance and long‐term stability of a novel 3‐in‐1 X‐ray system for brachytherapy

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

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