Review of advanced catheter technologies in radiation oncology brachytherapy procedures

Zhou, Jun; Zamdborg, Leonid; Sebastian, Evelyn

doi:10.2147/cmar.s46042

Cited by 28 publications

(47 citation statements)

References 115 publications

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“…show that the positioning error is proportional to

d_{normalFG}^{4}

and Zhou et al. show that the combination of large field generator distances and interferences of a typical brachytherapy environment yields the largest error 19, 20. The data at

d_{normaltable} = 120 mm

and over all d FG reported in Fig.…”

Section: Discussionmentioning

confidence: 85%

“…A number of studies showed that EMT is a viable approach for quality assurance and implant tracking in brachytherapy 19. This study is the technical foundation of a recently initiated clinical investigation to study potential changes of the implant geometry in interstitial HDR brachytherapy of breast cancer by EMT.…”

Section: Discussionmentioning

confidence: 95%

“…A comprehensive overview of the currently used techniques is provided by Zhou et al 19. For rigid objects such as the phantoms used in accuracy studies registration between EMT and reference data are a feasible alternative even though potentially introduced systematic shifts could be canceled out by the registration.…”

Section: Discussionmentioning

confidence: 99%

“…In case, the implant is compared to anatomic structures of the patient, for example, to perform dose calculation, or if inter‐fractional changes of the patient's anatomy with respect to CT scan are of interest, registration needs landmarks visible in both techniques. As recently reported by Zhou et al., three fiducial sensors are a starting point for rigid registration of the coordinate systems with uncertainties related to reproducibly placing the fiducials 19. A combination of EMT with surface imaging could improve the registration and also be sensitive to potential non‐rigid inter‐fractional changes of the patient's anatomy, for example, changes in breast posture.…”

Section: Discussionmentioning

confidence: 99%

“…A review of the technological fundamentals and the clinical applications is given by Franz et al 18. In the last years, EMT was also proposed for interstitial brachytherapy mainly addressing implant reconstruction and error detection,19 i.e., applications in‐line with the ongoing efforts to increase quality assurance (QA) in brachytherapy.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy

Kellermeier

Herbolzheimer

Kreppner

et al. 2017

J Applied Clin Med Phys

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Electromagnetic Tracking (EMT) is a novel technique for error detection and quality assurance (QA) in interstitial high dose rate brachytherapy (HDR‐iBT). The purpose of this study is to provide a concept for data acquisition developed as part of a clinical evaluation study on the use of EMT during interstitial treatment of breast cancer patients. The stability, accuracy, and precision of EMT‐determined dwell positions were quantified. Dwell position reconstruction based on EMT was investigated on CT table, HDR table and PDR bed to examine the influence on precision and accuracy in a typical clinical workflow. All investigations were performed using a precise PMMA phantom. The track of catheters inserted in that phantom was measured by manually inserting a 5 degree of freedom (DoF) sensor while recording the position of three 6DoF fiducial sensors on the phantom surface to correct motion influences. From the corrected data, dwell positions were reconstructed along the catheter's track. The accuracy of the EMT‐determined dwell positions was quantified by the residual distances to reference dwell positions after using a rigid registration. Precision and accuracy were investigated for different phantom‐table and sensor‐field generator (FG) distances. The measured precision of the EMT‐determined dwell positions was ≤ 0.28 mm (95th percentile). Stability tests showed a drift of 0.03 mm in the first 20 min of use. Sudden shaking of the FG or (large) metallic objects close to the FG degrade the precision. The accuracy with respect to the reference dwell positions was on all clinical tables < 1 mm at 200 mm FG distance and 120 mm phantom‐table distance. Phantom measurements showed that EMT‐determined localization of dwell positions in HDR‐iBT is stable, precise, and sufficiently accurate for clinical assessment. The presented method may be viable for clinical applications in HDR‐iBT, like implant definition, error detection or quantification of uncertainties. Further clinical investigations are needed.

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“…show that the positioning error is proportional to

d_{normalFG}^{4}

and Zhou et al. show that the combination of large field generator distances and interferences of a typical brachytherapy environment yields the largest error 19, 20. The data at

d_{normaltable} = 120 mm

and over all d FG reported in Fig.…”

Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy

Kellermeier

Herbolzheimer

Kreppner

et al. 2017

J Applied Clin Med Phys

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Deep‐learning‐assisted algorithm for catheter reconstruction during MR‐only gynecological interstitial brachytherapy

Shaaer

Paudel

Smith

et al. 2021

J Applied Clin Med Phys

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Magnetic resonance imaging (MRI) offers excellent soft-tissue contrast enabling the contouring of targets and organs at risk during gynecological interstitial brachytherapy procedure. Despite its advantage, one of the main obstacles preventing a transition to an MRI-only workflow is that implanted plastic catheters are not reliably visualized on MR images. This study aims to evaluate the feasibility of a deep-learning-based algorithm for semiautomatic reconstruction of interstitial catheters during an MR-only workflow. MR images of 20 gynecological patients were used in this study. Note that 360 catheters were reconstructed using T1-and T2-weighted images by five experienced brachytherapy planners. The mean of the five reconstructed paths were used for training (257 catheters), validation (15 catheters), and testing/evaluation (88 catheters). To automatically identify and localize the catheters, a two-dimensional (2D) U-net algorithm was used to find their approximate location in each image slice. Once localized, thresholding was applied to those regions to find the extrema, as catheters appear as bright and dark regions in T1-and T2-weighted images, respectively. The localized dwell positions of the proposed algorithm were compared to the ground truth reconstruction. Reconstruction time was also evaluated. A total of 34 009 catheter dwell positions were evaluated between the algorithm and all planners to estimate the reconstruction variability. The average variation was 0.97 ± 0.66 mm. The average reconstruction time for this approach was 11 ± 1 min, compared with 46 ± 10 min for the expert planners. This study suggests that the proposed deep learning, MR-based framework has potential to replace the conventional manual catheter reconstruction. The adoption of this approach in the brachytherapy workflow is expected to improve treatment efficiency while reducing planning time, resources, and human errors.

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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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Review of advanced catheter technologies in radiation oncology brachytherapy procedures

Cited by 28 publications

References 115 publications

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy

Deep‐learning‐assisted algorithm for catheter reconstruction during MR‐only gynecological interstitial brachytherapy

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

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