Electromagnetic tracking for treatment verification in interstitial brachytherapy

Bert, Christoph; Kellermeier, Markus; Tanderup, Kari

doi:10.5114/jcb.2016.63356

Cited by 31 publications

(40 citation statements)

References 27 publications

(45 reference statements)

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“…Researchers have summarized the errors and variations in brachytherapy along with their potential for detection by each verification method 21, 22. Not all events can be detected by a single verification method.…”

Section: Discussionmentioning

confidence: 99%

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

Otani

Sumida

Nose

et al. 2018

J Applied Clin Med Phys

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PurposeThe major errors in HDR brachytherapy are related to treatment distance, almost all of which are caused by incorrect applicator information. The aim of this study is to propose a quick pretreatment verification method to evaluate channel length and dwell position with a transparent applicator, which, in addition, is suitable as an education tool to assist in the understanding of the applicator structure.MethodsA transparent applicator model was fabricated using a three‐dimensional printer and transparent resin. Its aim is to be a replica of a real gynecological applicator. The pretreatment verification is performed by observing the planned dwell positions of a check cable inside a transparent applicator. A digital camera acquired images and the dwell positions of the radioactive source and check cable were evaluated by comparing them with respect to the theoretical dwell positions marked by the proper x‐ray marker. The potential effectiveness of verification using a transparent applicator was also evaluated using brachytherapy events reported in the literature.ResultsThe transparent applicator closely resembles the real applicator in shape and had an error of less than 0.2 mm. The average dwell position displacement between the radioactive source and check cable was 0.4 mm. The analysis of brachytherapy events showed that channel‐length, dwell‐position, and step‐size errors made up 50% of all events, but affected 64% of all patients.ConclusionsThe transparent applicator model enables a noninvasive, repeatable verification of the channel length and dwell positions to be performed before treatment. This verification has the potential to help prevent common errors in treatment delivery. In addition, the transparent applicator model can be used as a teaching tool to help clinicians understand the operation of the applicator, lowering the risk of events.

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Section: Discussionmentioning

confidence: 99%

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

Otani

Sumida

Nose

et al. 2018

J Applied Clin Med Phys

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“…Additional details of the patient cohort, the EMT recording, and the necessary data preprocessing were given in Refs. , respectively.…”

Section: Data Acquisitionmentioning

confidence: 97%

“…An individual treatment plan (CT data) defines dwell positions and dwell times of the radiation source inside the catheter. Subsequent radiation source localization is effected via electromagnetic tracking (EMT) . But the signals recorded in every EMT session refer to a different coordinate system.…”

Section: Introductionmentioning

confidence: 99%

“…This study investigates how EMT can be performed without any such external registration by employing suitable point set registration methods which map the collected dwell position point sets onto each other thus rendering them comparable. In this study, we compare rigid and nonrigid coherent point drift (CPD) registration with an MDS registration . We argue that nrCPD deems unsuitable for EMT in HDR‐BT as it does not preserve the point set topology.…”

Section: Introductionmentioning

confidence: 99%

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Technical Note: A comparison of point set registration methods for electromagnetic tracking

et al. 2019

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Purpose High dose rate brachytherapy applies intense and destructive radiation. A treatment plan defines radiation source dwell positions to avoid irradiating healthy tissue. The study discusses methods to quantify any positional changes of source locations along the various treatment sessions. Methods Electromagnetic tracking (EMT) localizes the radiation source during the treatment sessions. But in each session the relative position of the patient relative to the filed generator is changed. Hence, the measured dwell point sets need to be registered onto each other to render them comparable. Two point set registration techniques are compared: a probabilistic method called coherent point drift (CPD) and a multidimensional scaling (MDS) technique. Results Both enable using EMT without external registration and achieve very similar results with respect to dwell position determination of the radiation source. Still MDS achieves smaller grand average deviations (CPD‐rPSR: MD = 2.55 mm, MDS‐PSR: MD = 2.15 mm) between subsequent dwell position determinations, which also show less variance (CPD‐rPSR: IQR = 4 mm, MDS‐PSR: IQR = 3 mm). Furthermore, MDS is not based on approximations and does not need an iterative procedure to track sensor positions inside the implanted catheters. Conclusion Although both methods achieve similar results, MDS is to be preferred over rigid CPD while nonrigid CPD is unsuitable as it does not preserve topology.

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“…Fluoroscopy also exposes the patient and medical team to ionizing radiation. Electromagnetic reconstruction [1,29] is a recent method to determine catheter placement. A position sensor is tracked as it is pulled through each catheter.…”

Section: Introductionmentioning

confidence: 99%

Needle Navigation and Catheter Reconstruction for Breast Brachytherapy Using Open Source Software

2019

APH

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Interstitial breast brachytherapy is a method to deliver radiation therapy directly to the site of cancer. It is a challenging procedure because of issues in localizing the seroma, needles, and catheters within the soft tissue. In this paper we present two opensource technologies based on electromagnetic tracking: a navigation system to help target needles using a tracked needle guide, and software for electromagnetic reconstruction of catheter paths. These technologies were validated phantom studies. We found that the navigation system helped a radiation oncologist to target needles more accurately than under ultrasound guidance (60 needles under each condition, 3.8 vs 3.3 mm placement error, p = 0.04) and that reconstructed catheter paths were accurate within 0.6 mm to those determined on CT scans (144 catheters were compared to the 1.2 mm voxel size of CT scans, p < 0.001). We conclude that these technologies accurately localize anatomy and instruments in our study.

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Electromagnetic tracking for treatment verification in interstitial brachytherapy

Cited by 31 publications

References 27 publications

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

High‐dose rate intracavitary brachytherapy pretreatment dwell position verification using a transparent applicator

Technical Note: A comparison of point set registration methods for electromagnetic tracking

Needle Navigation and Catheter Reconstruction for Breast Brachytherapy Using Open Source Software

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