Single-Center Evaluation of Treatment Success Using Two Different Protocols for MRI-Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer.

Objectives: To assess differences in 24-month oncologic and functional outcomes in men with low to intermediate-risk prostate cancer treated with MRI-guided transurethral ultrasound ablation (TULSA) using intentionally conservative versus intensified treatment parameters.

Patients And Methods: Patients from a single center involved in two multicenter trials were included in this analysis. This included 14 of 30 patients with Gleason 3 + 3 from a Phase I study using intentionally conservative treatment parameters, and 15 of 115 patients with Gleason ≤ 3 + 4 from a pivotal study using intensified parameters.

Magnetic resonance imaging-guided transurethral ultrasound ablation in patients with localised prostate cancer: 3-year outcomes of a prospective Phase I study.

Objectives: To report the 3-year follow-up of a Phase I study of magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (TULSA) in 30 men with localised prostate cancer. Favourable 12-month safety and ablation precision were previously described.

Patients And Methods: As a mandated safety criterion, TULSA was delivered as near whole-gland ablation, applying 3-mm margins sparing 10% of peripheral prostate tissue in 30 men.

Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Cancer.

Purpose: Magnetic resonance imaging-guided transurethral ultrasound ablation uses directional thermal ultrasound under magnetic resonance imaging thermometry feedback control for prostatic ablation. We report 12-month outcomes from a prospective multicenter trial (TACT).

Materials And Methods: A total of 115 men with favorable to intermediate risk prostate cancer across 13 centers were treated with whole gland ablation sparing the urethra and apical sphincter.

MR Imaging-Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer: Preliminary Experience from a Single Center in a Prospective, Multi-Center, Single-Arm Clinical Trial.

This report details a single-center experience of using magnetic resonance imaging-guided transurethral ultrasound ablation (TULSA) for whole-gland prostate treatment. Nine men with organ-confined low-to-intermediate-risk prostate cancer underwent the TULSA procedure. The primary endpoint of reduction of more than 75% was achieved in 8 of 9 patients, and all patients demonstrated a histologic benefit at 12-month biopsy.

Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Tissue in Patients with Localized Prostate Cancer: A Prospective Phase 1 Clinical Trial.

Background: Magnetic resonance imaging-guided transurethral ultrasound ablation (MRI-TULSA) is a novel minimally invasive technology for ablating prostate tissue, potentially offering good disease control of localized cancer and low morbidity.

Objective: To determine the clinical safety and feasibility of MRI-TULSA for whole-gland prostate ablation in a primary treatment setting of localized prostate cancer (PCa).

Design, Setting, And Participants: A single-arm prospective phase 1 study was performed at three tertiary referral centers in Canada, Germany, and the United States.

Magnetic resonance image guided transurethral ultrasound prostate ablation: a preclinical safety and feasibility study with 28-day followup.

Purpose: We determine the safety and feasibility of magnetic resonance image guided transurethral ultrasound prostate ablation using active temperature feedback control in a preclinical canine model with 28-day followup.

Materials And Methods: After a long acclimatization period we performed ultrasound treatment in 8 subjects using the magnetic resonance image guided TULSA-PRO™ transurethral ultrasound prostate ablation system. Comprehensive examinations and observations were done before and throughout the 28-day followup, including assessment of clinically significant treatment related adverse events.

MR imaging-controlled transurethral ultrasound therapy for conformal treatment of prostate tissue: initial feasibility in humans.

Purpose: To evaluate the feasibility and safety of magnetic resonance (MR) imaging-controlled transurethral ultrasound therapy for prostate cancer in humans.

Materials And Methods: This pilot study was approved by the institutional review board and was performed in eight men (mean age, 60 years; range, 49-70 years) with localized prostate cancer (Gleason score≤7, prostate-specific antigen level #15 μg/L) immediately before radical prostatectomy. All patients provided written informed consent.

Coagulation of human prostate volumes with MRI-controlled transurethral ultrasound therapy: results in gel phantoms.

Purpose: The feasibility and safety of magnetic resonance imaging (MRI)-controlled transurethral ultrasound therapy were demonstrated recently in a preliminary human study in which a small subvolume of prostate tissue was treated prior to radical prostatectomy. Translation of this technology to full clinical use, however, requires the capability to generate thermal coagulation in a volume up to that of the prostate gland itself. The aim of this study was to investigate the parameters required to treat a full 3D human prostate accurately with a multi-element transurethral applicator and multiplanar MR temperature control.

Investigation of power and frequency for 3D conformal MRI-controlled transurethral ultrasound therapy with a dual frequency multi-element transducer.

Transurethral ultrasound therapy uses real-time magnetic resonance (MR) temperature feedback to enable the 3D control of thermal therapy accurately in a region within the prostate. Previous canine studies showed the feasibility of this method in vivo. The aim of this study was to reduce the procedure time, while maintaining targeting accuracy, by investigating new combinations of treatment parameters.

MRI-controlled transurethral ultrasound therapy for localised prostate cancer.

Minimally invasive treatments for localised prostate cancer are being developed with the aim of achieving effective disease control with low morbidity. High-temperature thermal therapy aimed at producing irreversible thermal coagulation of the prostate gland is attractive because of the rapid onset of thermal injury, and the immediate visualisation of tissue response using medical imaging. High-intensity ultrasound therapy has been shown to be an effective means of achieving thermal coagulation of prostate tissue using minimally invasive devices inserted into the rectum, urethra, or directly into the gland itself.

3D conformal MRI-controlled transurethral ultrasound prostate therapy: validation of numerical simulations and demonstration in tissue-mimicking gel phantoms.

MRI-controlled transurethral ultrasound therapy uses a linear array of transducer elements and active temperature feedback to create volumes of thermal coagulation shaped to predefined prostate geometries in 3D. The specific aims of this work were to demonstrate the accuracy and repeatability of producing large volumes of thermal coagulation (>10 cc) that conform to 3D human prostate shapes in a tissue-mimicking gel phantom, and to evaluate quantitatively the accuracy with which numerical simulations predict these 3D heating volumes under carefully controlled conditions. Eleven conformal 3D experiments were performed in a tissue-mimicking phantom within a 1.

Simulation study on the heating of the surrounding anatomy during transurethral ultrasound prostate therapy: a 3D theoretical analysis of patient safety.

Purpose: MRI-guided transurethral ultrasound therapy can generate highly accurate volumes of thermal coagulation conforming to 3D human prostate geometries. This work simulated, quantified, and evaluated the thermal impact of these treatments on the rectum, pelvic bone, neurovascular bundles (NVBs), and urinary sphincters because damage to these structures can lead to complications.

Methods: Twenty 3D anatomical models of prostate cancer patients were used with detailed bioacoustic simulations incorporating an active feedback algorithm which controlled a rotating, planar ultrasound transducer (17, 4 x 3 mm2 elements, 10 W(acoustic)/cm2).

Analysis of the spatial and temporal accuracy of heating in the prostate gland using transurethral ultrasound therapy and active MR temperature feedback.

A new MRI-guided therapy is being developed as a minimally invasive treatment for localized prostate cancer utilizing high-intensity ultrasound energy to generate a precise region of thermal coagulation within the prostate gland. The purpose of this study was to evaluate in vivo the capability to produce a spatial heating pattern in the prostate that accurately matched the shape of a target region using transurethral ultrasound heating and active MR temperature feedback. Experiments were performed in a canine model (n = 9) in a 1.

Quantitative analysis of 3-D conformal MRI-guided transurethral ultrasound therapy of the prostate: theoretical simulations.

Purpose: The capability of MRI-guided transurethral ultrasound therapy to produce continuous regions of thermal coagulation that conform to human prostate geometries was evaluated using 3-D anatomical models of prostate cancer patients.

Methods: Numerical simulations incorporating acoustic and biothermal modeling and a novel temperature control feedback algorithm were used to evaluate treatment accuracy of a rotating dual-frequency multi-element transducer. Treatments were simulated on twenty anatomical models obtained from the manual segmentation of the prostate and surrounding structures on MR images of prostate cancer patients obtained prior to radical prostatectomy.

Analysis of factors important for transurethral ultrasound prostate heating using MR temperature feedback.

The feasibility of using MR thermometry for temperature feedback to control a transurethral ultrasound heating applicator with planar transducers was investigated. The sensitivity of a temperature-based feedback algorithm to spatial (control point area, slice thickness, angular alignment) and non-spatial (imaging time, temperature uncertainty) parameters was evaluated through numerical simulations. The angular alignment of the control point with the ultrasound beam was an important parameter affecting the average spatial error in heat delivery.

Method for MRI-guided conformal thermal therapy of prostate with planar transurethral ultrasound heating applicators.

A method for conformal prostate thermal therapy using transurethral ultrasound heating applicators incorporating planar transducers is described. The capability to shape heating patterns to the geometry of the prostate gland from a single element in a multi-element heating applicator was evaluated using Bioheat transfer modelling. Eleven prostate geometries were obtained from patients who underwent MR imaging of the prostate gland prior to radical prostatectomy.