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Session: Therapy General ePoster Viewing [Return to Session]

The Challenge of Base Depth Needle Placement in Prostate Brachytherapy: Video Documentation, Phantom Simulation, Manual and Mechanical Solutions

P McLaughlin1,2*, C Evans2, G Hixon1, V Narayana1,2, (1) Ascension Providence (2) University of Michigan, Ann Arbor, MI


PO-GePV-T-44 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: Ultrasound guided prostate brachytherapy implants are challenging as the needles used for source placement may not reach the base of the prostate. In this study, we have documented the mechanisms of needle placement and propose the use of a high speed pneumatic mechanical assist to overcome needle placement challenges.

Methods: High resolution recording of the ultrasound prostate implant procedure and needle placement was captured in 50 patients. Tissue displacement and needle deflection in the prostate was documented. The position of the needle tip as a function of the speed of needle placement was observed. A prostate phantom capable of displacement in the superior-inferior dimension was developed and used to test needle binding and needle displacement in the phantom. Finally, a high speed pneumatic mechanical assist device was developed and tested on the phantom.

Results: Analysis of the high-resolution videos show that the speed with which the needle penetrates the prostate is crucial to reaching the base of the prostate. The phenomena of needle binding wherein the needle binds to the prostate and displaces the entire prostate cephalad was clearly documented in the video recordings. A timid approach to needle placement tented the prostate compared to a high-speed needle stick approach. High-speed needle placement in the phantom showed a prostate displacement of up to 2 cm cephalad. The use of the pneumatic delivery device reduced the prostate base displacement to 1 mm.

Conclusion: Needles placed in the prostate under ultrasound guidance show numerous non-ideal delivery patterns. Use of high-resolution videos fully document the challenge of needles reaching the base of the prostate. The use of a pneumatic device indicates that the speed of the needle placement is crucial to reaching the base of the prostate as it prevents the needle from binding to the prostate and displacing it.


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