In vivo validation of a therapy planning system for laser-induced thermotherapy (LITT) of liver malignancies

Lehmann, Kai S.; Frericks, Bernd; Holmer, Christoph; Schenk, Andrea; Weihusen, Andreas; Knappe, Verena; Zurbuchen, Urte; Peitgen, Heinz O.; Buhr, H. J.; Ritz, JP

doi:10.1007/s00384-011-1175-y

Cited by 20 publications

(14 citation statements)

References 35 publications

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“…The automated aspect of this system's robotic arm offers additional unique advantages. Whereas the robotic guide arm of other existing devices must be manually positioned in the vicinity of the target before subsequent end effector localisation is achieved automatically or via joystick use, the robotic guide arm of this platform automatically moves from its docked position to the skin entry point based on the physician dictated plan [17, 20, 21, 30]. As this platform abrogates the need for manual movement of the device after initial registration and docking, the physician can focus on the biopsy and ablation planning steps instead of manually moving the robot during the procedure.…”

Section: Discussionmentioning

confidence: 99%

“…Early phantom and clinical experience with robotic navigation systems suggest procedural accuracy, reduced procedure time and reduced patient radiation exposure compared with freehand techniques [13–19]. Experience with software systems enabling ablation planning has also been favourably described [20, 21]. In this study, an IR assistance platform was evaluated that combines navigational software and robotic guidance to facilitate percutaneous biopsy and ablation probe placement.…”

Section: Introductionmentioning

confidence: 99%

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Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Koethe

Velusamy³

et al. 2013

Eur Radiol

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Objective To compare the accuracy of a robotic interventional radiologist (IR) assistance platform with a standard freehand technique for computed-tomography (CT)-guided biopsy and simulated radiofrequency ablation (RFA). Methods The accuracy of freehand single-pass needle insertions into abdominal phantoms was compared with insertions facilitated with the use of a robotic assistance platform (n = 20 each). Post-procedural CTs were analysed for needle placement error. Percutaneous RFA was simulated by sequentially placing five 17-gauge needle introducers into 5-cm diameter masses (n = 5) embedded within an abdominal phantom. Simulated ablations were planned based on pre-procedural CT, before multi-probe placement was executed freehand. Multi-probe placement was then performed on the same 5-cm mass using the ablation planning software and robotic assistance. Post-procedural CTs were analysed to determine the percentage of untreated residual target. Results Mean needle tip-to-target errors were reduced with use of the IR assistance platform (both P < 0.0001). Reduced percentage residual tumour was observed with treatment planning (P = 0.02). Conclusion Improved needle accuracy and optimised probe geometry are observed during simulated CT-guided biopsy and percutaneous ablation with use of a robotic IR assistance platform. This technology may be useful for clinical CT-guided biopsy and RFA, when accuracy may have an impact on outcome.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Koethe

Velusamy³

et al. 2013

Eur Radiol

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“…[47][48][49] Recent studies have validated the temperature and thermal damage profile computed using Pennes model with experiments in perfused ex vivo liver, as well as in vivo animal models. [49][50][51] The tissue acoustic and thermal properties used in the model for Eqs. (1) and (2) are listed in Table II.…”

Section: Iid Bioacoustic-thermal Modelmentioning

confidence: 99%

Multiple applicator hepatic ablation with interstitial ultrasound devices: Theoretical and experimental investigation

et al. 2012

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Purpose: To evaluate multiple applicator implant configurations of interstitial ultrasound devices for large volume ablation of liver tumors. Methods: A 3D bioacoustic-thermal model using the finite element method was implemented to assess multiple applicator implant configurations for thermal ablation with interstitial ultrasound energy. Interstitial applicators consist of linear arrays of up to four 10 mm-long tubular ultrasound transducers, each under separate and dynamic power control, enclosed within a water-cooled delivery catheter (2.4 mm OD). The authors considered parallel implants with two and three applicators (clustered configuration), spaced 2-3 cm apart, to simulate open surgical placement. In addition, the authors considered two applicator implants with applicators converging and diverging at angles of ∼20• , 30• , and 45• to simulate percutaneous placement. Heating experiments (10-15 min) were performed and compared against simulations employing the same experimental parameters. To estimate the performance of parallel, multiple applicator configurations in an in vivo setting, simulations were performed taking into account a range of blood perfusion levels (0, 5, 12, and 15 kg m −3 s −1 ) that may occur in tumors of varying vascularity. The impact of tailoring the power supplied to individual transducer elements along the length of applicators is explored for applicators inserted in non-parallel (converging and diverging) configurations. Thermal dose (t 43 > 240 min) and temperature thresholds (T > 52• C) were used to define the ablation zones, with dynamic changes to tissue acoustic and thermal properties incorporated within the model. Results: Experiments in ex vivo bovine liver yielded ablation zones ranging between 4.0-5.6 cm × 3.2-4.9 cm, in cross section. Ablation zone dimensions predicted by simulations with similar parameters to the experiments were in close agreement (within 5 mm). Simulations of in vivo heating showed that 15 min heating and interapplicator spacing less than 3 cm are required to obtain contiguous, complete ablation zones. The ability to create complete ablation zone profiles for nonparallel implants was illustrated by tailoring applied power levels along the length of applicators. Conclusions: Parallel implants consisting of three interstitial ultrasound applicators in a triangular configuration yield complete ablation zones measuring up to 6.2 cm × 5.7 cm after 15 min heating. At larger interapplicator spacing, the level of blood perfusion in the tumor may yield indentations along the periphery of the ablation zone. Tailoring applied power along the length of the applicator can accommodate for nonparallel implants, without compromising safety.

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“…4), with increased volumes resulting from increased velocity settings (F (1,20) ¼ 5840.623; P < 0.0005), and reduced volumes resulting from greater tightness positions (F (4,20) ¼ 1325.680; P < 0.0005). Critical however, was the examination of the interaction of the two factors, which further revealed a statistically significant effect (F (4,20) ¼ 103.839; P < 0.0005), indicating that as the Touhey cap was tightened, this lessened the increases imparted by the higher pump velocity settings.…”

Section: Effect Of Bone Anchor Touhey Cap On Flow Ratementioning

confidence: 98%

Assessment of irrigation dynamics in magnetic-resonance guided laser induced thermal therapy (MRgLITT)

et al. 2015

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In vivo validation of a therapy planning system for laser-induced thermotherapy (LITT) of liver malignancies

Cited by 20 publications

References 35 publications

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

Multiple applicator hepatic ablation with interstitial ultrasound devices: Theoretical and experimental investigation

Assessment of irrigation dynamics in magnetic-resonance guided laser induced thermal therapy (MRgLITT)

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