scholarly journals Photoacoustic assisted device guidance and thermal lesion imaging for radiofrequency ablation

2019 ◽  
Author(s):  
Francis Kalloor Joseph ◽  
Srirang Manohar
Keyword(s):  
Radiofrequency Ablation ◽  
Thermal Lesion ◽  
Device Guidance

scholarly journals Thermal and electric Characteristics of High-power Short-duration Radiofrequency Ablation and Standard Radiofrequency Ablation: A Computer Simulation Study

2021 ◽  
Author(s):  
Kaihao Gu ◽  
Shengjie Yan ◽  
Xiaomei Wu
Keyword(s):  
Radiofrequency Ablation ◽  
Short Duration ◽  
High Power ◽  
Lesion Size ◽  
Lesion Volume ◽  
Rf Ablation ◽  
Thermal Lesion ◽  
Lesion Depth ◽  
Lesion Diameter ◽  
Rate Of Increase

Abstract Background: High power-short duration ablation is an emerging conception for cardiac RF treatment. But the biophysical ablation properties of this technique have not been fully explored. This study compared the electric field characteristics and thermal lesion dimension in High power-short duration (HP-SD) radio frequency (RF) ablation and standard RF ablation by using the finite element method. Results: The results demonstrated that the lesion size and temperature in HP–SD RF ablation increased faster than standard RF ablation. The thermal lesion volume in both ablation modes demonstrated a linear increase and the rate of increase of HP–SD RF ablation grew faster than that of standard RF ablation. For HP–SD application at 50 W for 5 s, the lesion depth was shallower (1.74 to 2.1 mm vs 2.40 to 3.15 mm) and the surface lesion diameter was broader (2.76 to 3.32 mm vs 2.42 to 2.66 mm) than that for standard RF ablation at 25 W for 30 s. Conclusion: Compared with standard RF ablation, HP–SD RF ablation creates a broader lesion width and surface lesion diameter but shallower lesion depth, with a faster increase in temperature. HP–SD ablation is more able to achieve uniform and contiguous lesion shape, which is a suitable for point-to-point RF ablation procedures.Higher temperature was formed in deeper space of cardiac tissue in HP–SD ablation. The duration of HP–SD ablation should be strictly controlled for preventing the steam occur in tissue.

scholarly journals Annular Fiber Probe for Interstitial Illumination in Photoacoustic Guidance of Radiofrequency Ablation

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4458
Author(s):  
Hindrik Kruit ◽  
Kalloor Joseph Francis ◽  
Elina Rascevska ◽  
Srirang Manohar
Keyword(s):  
Radiofrequency Ablation ◽  
Real Time ◽  
Optical Fibers ◽  
Liver Tumors ◽  
Ex Vivo ◽  
Bovine Liver ◽  
Needle Guidance ◽  
Recurrence Rates ◽  
Fiber Probe ◽  
Device Guidance

Unresectable liver tumors are commonly treated with percutaneous radiofrequency ablation (RFA). However, this technique is associated with high recurrence rates due to incomplete tumor ablation. Accurate image guidance of the RFA procedure contributes to successful ablation, but currently used imaging modalities have shortcomings in device guidance and treatment monitoring. We explore the potential of using photoacoustic (PA) imaging combined with conventional ultrasound (US) imaging for real-time RFA guidance. To overcome the low penetration depth of light in tissue, we have developed an annular fiber probe (AFP), which can be inserted into tissue enabling interstitial illumination of tissue. The AFP is a cannula with 72 optical fibers that allows an RFA device to slide through its lumen, thereby enabling PA imaging for RFA device guidance and ablation monitoring. We show that the PA signal from interstitial illumination is not affected by absorber-to-surface depth compared to extracorporeal illumination. We also demonstrate successful imaging of the RFA electrodes, a blood vessel mimic, a tumor-mimicking phantom, and ablated liver tissue boundaries in ex vivo chicken and bovine liver samples. PA-assisted needle guidance revealed clear needle tip visualization, a notable improvement to current US needle guidance. Our probe shows potential for RFA device guidance and ablation detection, which potentially aids in real-time monitoring.

scholarly journals A row-generation approach for simultaneous multiple needle trajectory planning in radiofrequency ablation

2021 ◽  
Author(s):  
Shefali Kulkarni-Thaker ◽  
Dionne M Aleman ◽  
Aaron Fenster
Keyword(s):  
Radiofrequency Ablation ◽  
Trajectory Planning ◽  
Programming Model ◽  
Treatment Plan ◽  
Set Cover ◽  
Thermal Lesion ◽  
Clinical Criteria ◽  
Damage Models ◽  
Needle Trajectory ◽  
First Time

Radiofrequency ablation is a thermal therapy for moderately-sized cancerous tumors. A target is killed with high temperatures obtained due to the current passed through one or more electrodes (needles) inserted into it. The needles' trajectory must be meticulously planned to prevent interference with dense organs like bone or puncturing of critical structures like veins. By approximating the thermal lesion to an ellipse, we predefine several valid needle trajectories and then solve an integer programming model to identify pairwise valid needle positions, that meet clinical criteria, using a variation of the classic set cover model. To improve the models' tractability and scalability, we use row generation-based decomposition techniques that determines pairwise validity using two different types of cuts. Finally, we analyze target and OAR damage using several thermal damage models. Thus, for the first time we present a full treatment plan that incorporates novel trajectory planning with thermal dose computations. Our method is tested on 12 liver targets: three targets each with four different surgical margins. We show promising results that meet clinical guidelines while obtaining full target coverage.

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