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

Boutaleb S, Racine E, Fillion O, Bonillas A, Hautvast G, Binnekamp D, Beaulieu L - J Contemp Brachytherapy (2015)

Bottom Line: 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.The 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.

View Article: PubMed Central - PubMed

Affiliation: Département de Radio-Oncologie et Centre de Recherche du CHU de Québec, Québec, Canada ; Département de Physique, de Génie Physique et d'Optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Canada.

ABSTRACT

Purpose: Accurate 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 methods: The 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.

Results: The 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.

Conclusions: The 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.

No MeSH data available.


Related in: MedlinePlus

Static positional tracking error as a function of different types and configurations of brachytherapy equipment with the setup of Figure 3: A TFT-LCD monitor supported by a metallic arm, an active or inactive cathodic screen (CRT) monitor as well as numerous metallic catheters surrounding the electromagnetic needle in the publications report using polycarbonate (PMMA) phantom
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Figure 0011: Static positional tracking error as a function of different types and configurations of brachytherapy equipment with the setup of Figure 3: A TFT-LCD monitor supported by a metallic arm, an active or inactive cathodic screen (CRT) monitor as well as numerous metallic catheters surrounding the electromagnetic needle in the publications report using polycarbonate (PMMA) phantom

Mentions: The results of the position error analysis are depicted in Figure 11. For each study case, a tracking reference measurement was first performed without the presence of any equipment, and a mean absolute positional error was computed. The components were then brought into place in vicinity of the EM needle or in periphery of the experimental zone and another measurement was performed. The difference between the two mean errors allowed to quantitatively assert the strength of the EM distortion generated by the considered equipment. It can be seen in Figure 11 that all three reference measurements produced absolute positional errors of approximately 1 mm, which is the result of the intrinsic noise level of the Aurora® EMTS. The presence of a CRT monitor (powered or not) and metallic catheters had virtually no influence on the mean positional error, inducing deviations of at most 0.1 mm from their respective reference values. However, as intuitively predicted, the metallic arm support generated a significant amount of EM distortion. Mean position error differences of approximately 0.5 mm are observed when the arm is located 10 cm away from the needle sensor, and distortion effects are still visible when it is moved further away at 30 cm. These observations are explained by the fact that typical metallic arm supports like the one used in this study are made of stainless steel, which is ferromagnetic in nature and also a relatively good conductor. Therefore, it can easily distorts EM fields. The metallic catheters, on the other hand, caused no important distortion due to their very thin medical grade metal coating.


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

Boutaleb S, Racine E, Fillion O, Bonillas A, Hautvast G, Binnekamp D, Beaulieu L - J Contemp Brachytherapy (2015)

Static positional tracking error as a function of different types and configurations of brachytherapy equipment with the setup of Figure 3: A TFT-LCD monitor supported by a metallic arm, an active or inactive cathodic screen (CRT) monitor as well as numerous metallic catheters surrounding the electromagnetic needle in the publications report using polycarbonate (PMMA) phantom
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643737&req=5

Figure 0011: Static positional tracking error as a function of different types and configurations of brachytherapy equipment with the setup of Figure 3: A TFT-LCD monitor supported by a metallic arm, an active or inactive cathodic screen (CRT) monitor as well as numerous metallic catheters surrounding the electromagnetic needle in the publications report using polycarbonate (PMMA) phantom
Mentions: The results of the position error analysis are depicted in Figure 11. For each study case, a tracking reference measurement was first performed without the presence of any equipment, and a mean absolute positional error was computed. The components were then brought into place in vicinity of the EM needle or in periphery of the experimental zone and another measurement was performed. The difference between the two mean errors allowed to quantitatively assert the strength of the EM distortion generated by the considered equipment. It can be seen in Figure 11 that all three reference measurements produced absolute positional errors of approximately 1 mm, which is the result of the intrinsic noise level of the Aurora® EMTS. The presence of a CRT monitor (powered or not) and metallic catheters had virtually no influence on the mean positional error, inducing deviations of at most 0.1 mm from their respective reference values. However, as intuitively predicted, the metallic arm support generated a significant amount of EM distortion. Mean position error differences of approximately 0.5 mm are observed when the arm is located 10 cm away from the needle sensor, and distortion effects are still visible when it is moved further away at 30 cm. These observations are explained by the fact that typical metallic arm supports like the one used in this study are made of stainless steel, which is ferromagnetic in nature and also a relatively good conductor. Therefore, it can easily distorts EM fields. The metallic catheters, on the other hand, caused no important distortion due to their very thin medical grade metal coating.

Bottom Line: 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.The 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.

View Article: PubMed Central - PubMed

Affiliation: Département de Radio-Oncologie et Centre de Recherche du CHU de Québec, Québec, Canada ; Département de Physique, de Génie Physique et d'Optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Canada.

ABSTRACT

Purpose: Accurate 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 methods: The 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.

Results: The 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.

Conclusions: The 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.

No MeSH data available.


Related in: MedlinePlus