An enhanced hybrid MRI thermometry technique for monitoring microwave thermal therapy

Alivar, Alaleh; Faridi, Pegah; Prakash, Punit; Natarajan, Balasubramaniam

doi:10.1117/12.2511666

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…While baseline drift is known to be a potential source of error during MRI thermometry for long durations [15], we observed the maximum drift over 60 min to be 0.4 °C; further, this level of drift could be corrected with established drift compensation techniques [39]- [41].…”

Section: Discussionmentioning

confidence: 66%

“…These data illustrate the ability of the proposed system to maintain localized heating to targeted regions over an extended duration of time. While baseline drift is known to be a potential source of error during MRI thermometry for long durations [15], we observed the maximum drift over 60 min to be 0.4 °C; further, this level of drift could be corrected with established drift compensation techniques [37][38][39].…”

Section: Discussionmentioning

confidence: 68%

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Simulation-based design and characterization of a microwave applicator for MR-guided hyperthermia experimental studies in small animals

Faridi

Bossmann

Prakash

2019

Biomed. Phys. Eng. Express

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Purpose:The objective of this study was to design and characterize a 2.45 GHz microwave hyperthermia applicator for delivering hyperthermia in experimental small animals to 2 -4 mm diameter targets located 1 -3 mm from the skin surface, with minimal heating of the surrounding tissue, under 14.1 T MRI real-time monitoring and feedback control. Materials and methods:An experimentally validated 3D computational model was employed to design and characterize a non-invasive directional water-cooled microwave hyperthermia applicator. We assessed the effects of: reflector geometry, monopole shape, cooling water temperature, and flow rate on spatial-temperature profiles. The system was integrated with realtime MR thermometry and feedback control to monitor and maintain temperature elevations in the range of 4 -5 °C at 1 -3 mm from the applicator surface. The quality of heating was quantified by determining the fraction of the target volume heated to the desired temperature, and the extent of heating in non-targeted regions.Results: Model-predicted hyperthermic profiles were in good agreement with experimental measurements (Dice Similarity Coefficient of 0.95 -0.99). Among the four considered criteria, a reflector aperture angle of 120 °, S-shaped monopole antenna with 0.6 mm displacement, and coolant flow rate of 150 ml/min were selected as the end result of the applicator design. The temperature of circulating water and input power were identified as free variables, allowing considerable flexibility in heating target sizes within varying distances from the applicator surface. 2 -4 mm diameter targets positioned 1 -3 mm from the applicator surface were heated to hyperthermic temperatures, with target coverage ratio ranging between 76 -93 % and 11 -26 % of non-targeted tissue heated. Conclusion:We have designed an experimental platform for MR-guided hyperthermia, incorporating a microwave applicator integrated with temperature-based feedback control to heat deep-seated targets for experimental studies in small animals.

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Section: Discussionmentioning

confidence: 66%