Electromagnetic navigation in medicine – basic issues, advantages and shortcomings, prospects of improvement

Baszyński, M.; Moron, Z.; Tewel, N.

doi:10.1088/1742-6596/238/1/012056

Cited by 5 publications

(5 citation statements)

References 5 publications

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“…Their development has been particularly prominent over the past decade and their use is becoming an increasingly interesting option among clinicians and researchers. The potential advantages that electromagnetic tracking system (EMTS) can bring to the field of image-guided surgery have been recognized [ 1 , 2 ], and their integration to existing medical devices for the development of new treatment or diagnostic procedures is undergoing a rapid evolution.…”

Section: Purposementioning

confidence: 99%

Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

Boutaleb¹,

Racine²,

Fillion³

et al. 2015

jcb

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PurposeAccurate insertion and overall needle positioning are key requirements for effective brachytherapy treatments. This work aims at demonstrating the accuracy performance and the suitability of the Aurora® V1 Planar Field Generator (PFG) electromagnetic tracking system (EMTS) for real-time treatment assistance in interstitial brachytherapy procedures.Material and methodsThe system's performance was characterized in two distinct studies. First, in an environment free of EM disturbance, the boundaries of the detection volume of the EMTS were characterized and a tracking error analysis was performed. Secondly, a distortion analysis was conducted as a means of assessing the tracking accuracy performance of the system in the presence of potential EM disturbance generated by the proximity of standard brachytherapy components.ResultsThe tracking accuracy experiments showed that positional errors were typically 2 ± 1 mm in a zone restricted to the first 30 cm of the detection volume. However, at the edges of the detection volume, sensor position errors of up to 16 mm were recorded. On the other hand, orientation errors remained low at ± 2° for most of the measurements. The EM distortion analysis showed that the presence of typical brachytherapy components in vicinity of the EMTS had little influence on tracking accuracy. Position errors of less than 1 mm were recorded with all components except with a metallic arm support, which induced a mean absolute error of approximately 1.4 mm when located 10 cm away from the needle sensor.ConclusionsThe Aurora® V1 PFG EMTS possesses a great potential for real-time treatment assistance in general interstitial brachytherapy. In view of our experimental results, we however recommend that the needle axis remains as parallel as possible to the generator surface during treatment and that the tracking zone be restricted to the first 30 cm from the generator surface.

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Section: Purposementioning

confidence: 99%

Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

Boutaleb¹,

Racine²,

Fillion³

et al. 2015

jcb

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“…This system has been widely used clinically to track surgical tools. 10,11 It also has been proposed [12][13][14] and investigated for real-time guidance of catheters in HDR Ir-192 brachytherapy. [15][16][17] We compared two prototype detectors, a PSD and an ISD, coupled to an EM sensor (with intrinsic submillimeter positional accuracy) for real-time dosimeter position tracking.…”

Section: Introductionmentioning

confidence: 99%

“…The EM system exploits a field generator that produces an inhomogeneous EM field, allowing a passive EM sensor (induction coils) to be tracked with 5 or 6 degrees‐of‐freedom (DOF) when it is placed within the field generator's active volume. This system has been widely used clinically to track surgical tools 10,11 . It also has been proposed 12–14 and investigated for real‐time guidance of catheters in HDR Ir‐192 brachytherapy 15–17 …”

Section: Introductionmentioning

confidence: 99%

A scintillation dosimeter with real‐time positional tracking information for in vivo dosimetry error detection in HDR brachytherapy

Tho,

Lavallée,

Beaulieu

2023

J Applied Clin Med Phys

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PurposeTo evaluate the performance of an electromagnetic (EM)‐tracked scintillation dosimeter in detecting source positional errors of IVD in HDR brachytherapy treatment.Materials and MethodsTwo different scintillator dosimeter prototypes were coupled to 5 degrees‐of‐freedom (DOF) EM sensors read by an Aurora V3 system. The scintillators used were a 0.3 × 0.4 × 0.4 mm3 ZnSe:O and a BCF‐60 plastic scintillator of 0.5 mm diameter and 2.0 mm in length (Saint‐Gobain Crystals). The sensors were placed at the dosimeter's tip at 20.0 mm from the scintillator. The EM sampling rate was 40/s while the scintillator signal was sampled at 100 000/s using two photomultiplier tubes from Hamamatsu (series H10722) connected to a data acquisition board. A high‐pass filter and a low‐pass filter were used to separate the light signal into two different channels. All measurements were performed with an afterloader unit (Flexitron‐Elekta AB, Sweden) in full‐scattered (TG43) conditions. EM tracking was further used to provide distance/angle‐dependent energy correction for the ZnSe:O inorganic scintillator. For the error detection part, lateral shifts of 0.5 to 3 mm were induced by moving the source away from its planned position. Indexer length (longitudinal) errors between 0.5 to 10 mm were also introduced. The measured dose rate difference was converted to a shift distance, with and without using the positional information from the EM sensor.ResultsThe inorganic scintillator had both a signal‐to‐noise‐ratio (SNR) and signal‐to‐background‐ratio (SBR) close to 70 times higher than those of the plastic scintillator. The mean absolute difference from the dose measurement to the dose calculated with TG‐43U1 was 1.5% ±0.7%. The mean absolute error for BCF‐60 detector was 1.7% when compared to TG‐43 calculations formalism. With the inorganic scintillator and EM tracking, a maximum area under the curve (AUC) gain of 24.0% was obtained for a 0.5‐mm lateral shift when using the EMT data with the ZnSe:O. Lower AUC gains were obtained for a 3‐mm lateral shifts with both scintillators. For the plastic scintillator, the highest gain from using EM tracking information occurred for a 0.5‐mm lateral shift at 20 mm from the source. The maximal gain (17.4%) for longitudinal errors was found at the smallest shifts (0.5 mm).ConclusionsThis work demonstrates that integrating EM tracking to in vivo scintillation dosimeters enables the detection of smaller shifts, by decreasing the dosimeter positioning uncertainty. It also serves to perform position‐dependent energy correction for the inorganic scintillator,providing better SNR and SBR, allowing detection of errors at greater distances from the source.

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“…Electromagnetic tracking systems are widely used in the medical field such as image‐guided surgery . Specifically, the Aurora EMT (NDI, Ontario, Canada) system uses a field generator which produces an electromagnetic field gradient within a cubic volume of 50 cm side, inside of which, a small sensor can be placed.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: Identification of an optimal electromagnetic sensor for in vivo electromagnetic‐tracked scintillation dosimeter for HDR brachytherapy

Tho

Beaulieu

2019

Medical Physics

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Purpose Brachytherapy is a treatment modality which delivers large doses of radiation in a reduced number of visits. Since a small number of large dose‐per‐fraction is administered in high dose rate brachytherapy, ensuring the right dose is delivered is highly critical. In this work, a scintillation detector is coupled to an electromagnetic (EM) sensor (NDI, Waterloo, ON, Canada) having submillimeter positional accuracy for real‐time tracking of the dosimeter position. However, adding an EM sensor adds materials in the path to the scintillator and thus could potentially perturb the dose measurements. This study assesses four different sensors for a plastic scintillation detector–EM sensor coupled dosimeter. Methods To confirm the perturbation presence, different sensors were placed in front of the scintillator so the radiation does not arrive to it directly. Variation of the distance between the sensor and the scintillator was used to quantify the effect on the signal at 0∘ and 90∘. To test the signal's angular dependence for each sensor, the signal measurement was taken from 0∘ to 90∘ with 10∘ increment. Results The Aurora 5DOF‐610090 sensor showed an increased signal of almost 20% with increasing beam angle. Sensors Aurora 5DOF‐610099, Aurora 5DOF‐610157, and Aurora Micro 6DOF‐610059 showed no significant angle dependance. The Aurora Micro 6DOF‐610059 and Aurora 5DOF‐610157 sensors' cable signal revealed no extra signal attenuation. The latter gives a smaller overall attenuation. Therefore, the Aurora 5DOF‐610157 sensor is chosen to be part of the novel dosimeter construction. It has a jitter error (average standard deviation of each individual measurement) of ±0.06 mm and a reproducibility of ±0.008 mm. In the optimal operating range, the average positional uncertainty is less than 0.2 mm. Average angle errors are not higher than 1.1∘. Conclusion It is feasible to integrate an EM tracking sensor to a plastic scintillation dosimeter with minimal impact to the collected signal as well as sufficient positional accuracy to keep dose uncertainty below 5%.

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Electromagnetic navigation in medicine – basic issues, advantages and shortcomings, prospects of improvement

Cited by 5 publications

References 5 publications

Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

A scintillation dosimeter with real‐time positional tracking information for in vivo dosimetry error detection in HDR brachytherapy

Technical Note: Identification of an optimal electromagnetic sensor for in vivo electromagnetic‐tracked scintillation dosimeter for HDR brachytherapy

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