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Gupta P, Heffter T, Zubair M, Hsu IC, Burdette EC, Diederich CJ. Treatment Planning Strategies for Interstitial Ultrasound Ablation of Prostate Cancer. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2024; 5:362-375. [PMID: 38899026 PMCID: PMC11186654 DOI: 10.1109/ojemb.2024.3397965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/28/2024] [Accepted: 05/03/2024] [Indexed: 06/21/2024] Open
Abstract
PURPOSE To develop patient-specific 3D models using Finite-Difference Time-Domain (FDTD) simulations and pre-treatment planning tools for the selective thermal ablation of prostate cancer with interstitial ultrasound. This involves the integration with a FDA 510(k) cleared catheter-based ultrasound interstitial applicators and delivery system. METHODS A 3D generalized "prostate" model was developed to generate temperature and thermal dose profiles for different applicator operating parameters and anticipated perfusion ranges. A priori planning, based upon these pre-calculated lethal thermal dose and iso-temperature clouds, was devised for iterative device selection and positioning. Full 3D patient-specific anatomic modeling of actual placement of single or multiple applicators to conformally ablate target regions can be applied, with optional integrated pilot-point temperature-based feedback control and urethral/rectum cooling. These numerical models were verified against previously reported ex-vivo experimental results obtained in soft tissues. RESULTS For generic prostate tissue, 360 treatment schemes were simulated based on the number of transducers (1-4), applied power (8-20 W/cm2), heating time (5, 7.5, 10 min), and blood perfusion (0, 2.5, 5 kg/m3/s) using forward treatment modelling. Selectable ablation zones ranged from 0.8-3.0 cm and 0.8-5.3 cm in radial and axial directions, respectively. 3D patient-specific thermal treatment modeling for 12 Cases of T2/T3 prostate disease demonstrate applicability of workflow and technique for focal, quadrant and hemi-gland ablation. A temperature threshold (e.g., Tthres = 52 °C) at the treatment margin, emulating placement of invasive temperature sensing, can be applied for pilot-point feedback control to improve conformality of thermal ablation. Also, binary power control (e.g., Treg = 45 °C) can be applied which will regulate the applied power level to maintain the surrounding temperature to a safe limit or maximum threshold until the set heating time. CONCLUSIONS Prostate-specific simulations of interstitial ultrasound applicators were used to generate a library of thermal-dose distributions to visually optimize and set applicator positioning and directivity during a priori treatment planning pre-procedure. Anatomic 3D forward treatment planning in patient-specific models, along with optional temperature-based feedback control, demonstrated single and multi-applicator implant strategies to effectively ablate focal disease while affording protection of normal tissues.
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Affiliation(s)
- Pragya Gupta
- Department of Radiation OncologyUniversity of California San FranciscoSan FranciscoCA94115USA
| | | | - Muhammad Zubair
- Department of Neurology and Neurological SciencesStanford UniversityStanfordCA94305USA
| | - I-Chow Hsu
- Department of Radiation OncologyUniversity of California San FranciscoSan FranciscoCA94115USA
| | | | - Chris J. Diederich
- Department of Radiation OncologyUniversity of California San FranciscoSan FranciscoCA94115USA
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AIUM Official Statement for the Statement on Biological Effects of Therapeutic Ultrasound. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2023; 42:E68-E73. [PMID: 37584480 DOI: 10.1002/jum.16315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/17/2023]
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Shoji S, Naruse J, Oda K, Kuroda S, Umemoto T, Nakajima N, Hasegawa M, Mukasa A, Koizumi N, Miyajima A. Current status and future outlook of ultrasound treatment for prostate cancer. J Med Ultrason (2001) 2023:10.1007/s10396-023-01368-x. [PMID: 37787881 DOI: 10.1007/s10396-023-01368-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/17/2023] [Indexed: 10/04/2023]
Abstract
Radical prostatectomy and radiation therapy are the standard treatment options for localized prostate cancer (PC). However, radical prostatectomy may cause the deterioration of urinary and sexual function, and radiation-induced hemorrhagic cystitis and severe rectal bleeding are risk factors for fatal conditions in patients after radiation therapy. With the recent development of magnetic resonance imaging (MRI) for the localization of clinically significant PC (csPC) and treatment modalities, "focal therapy", which cures csPC while preserving anatomical structures related to urinary and sexual functions, has become a minimally invasive treatment for localized PC. Based on the clinical results of transrectal high-intensity focused ultrasound (HIFU) for localized PC in the whole gland and focal therapy, HIFU is considered an attractive treatment option for focal therapy. Recently, the short-term clinical results of transurethral high-intensity directional ultrasound (HIDU) have been reported. With the resolution of some issues, HIDU may be commonly used for PC treatment similar to HIFU. Because HIFU and HIDU have limitations regarding the treatment of patients with large prostate calcifications and large prostate volumes, the proper use of these modalities will enable the treatment of any target area in the prostate. To establish a standard treatment strategy for localized PC, pair-matched and historically controlled studies are required to verify the oncological and functional outcomes of ultrasound treatment for patients with localized PC.
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Affiliation(s)
- Sunao Shoji
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
| | - Jun Naruse
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Kazuya Oda
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Satoshi Kuroda
- Department of Urology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan
| | - Tatsuya Umemoto
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Nobuyuki Nakajima
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Masanori Hasegawa
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Anju Mukasa
- Department of Mechanical and Intelligent Systems Engineering, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo, Japan
| | - Norihiro Koizumi
- Department of Mechanical and Intelligent Systems Engineering, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo, Japan
| | - Akira Miyajima
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
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Miura M, Takahashi S, Fukumoto M, Higashiyama H. Initial experience of transurethral ultrasound ablation of the prostate in Asia. BJUI COMPASS 2022; 3:405-407. [PMID: 36267195 PMCID: PMC9579879 DOI: 10.1002/bco2.175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/27/2022] [Accepted: 05/31/2022] [Indexed: 12/05/2022] Open
Affiliation(s)
| | - Satoru Takahashi
- Imaging Research Center Takatsuki General Hospital Takatsuki Japan
| | - Maiko Fukumoto
- Transplant Medical Support Office Sapporo Hokuyu Hospital Sapporo Japan
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Tollens F, Westhoff N, von Hardenberg J, Clausen S, Ehmann M, Zöllner FG, Adlung A, Bauer DF, Schoenberg SO, Nörenberg D. [MRI-guided minimally invasive treatment of prostate cancer]. Radiologe 2021; 61:829-838. [PMID: 34251481 DOI: 10.1007/s00117-021-00883-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2021] [Indexed: 11/27/2022]
Abstract
CLINICAL/METHODOLOGICAL ISSUE Multiparametric magnetic resonance imaging (mpMRI) of the prostate plays a crucial role in the diagnosis and local staging of primary prostate cancer. STANDARD RADIOLOGICAL METHODS Image-guided biopsy techniques such as MRI-ultrasound fusion not only allow guidance for targeted tissue sampling of index lesions for diagnostic confirmation, but also improve the detection of clinically significant prostate cancer. METHODOLOGICAL INNOVATIONS Minimally invasive, focal therapies of localized prostate cancer complement the treatment spectrum, especially for low- and intermediate-risk patients. PERFORMANCE In patients of low and intermediate risk, MR-guided, minimally invasive therapies could enable local tumor control, improved functional outcomes and possible subsequent therapy escalation. Further study results related to multimodal approaches and the application of artificial intelligence (AI) by machine and deep learning algorithms will help to leverage the full potential of focal therapies for prostate cancer in the upcoming era of precision medicine. ACHIEVEMENTS Completion of ongoing randomized trials comparing each minimally invasive therapy approach with established whole-gland procedures is needed before minimally invasive therapies can be implemented into existing treatment guidelines. PRACTICAL RECOMMENDATIONS This review article highlights minimally invasive therapies of prostate cancer and the key role of mpMRI for planning and conducting these therapies.
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Affiliation(s)
- Fabian Tollens
- Klinik für Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland
| | - Niklas Westhoff
- Klinik für Urologie und Urochirurgie, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Jost von Hardenberg
- Klinik für Urologie und Urochirurgie, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Sven Clausen
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Michael Ehmann
- Klinik für Strahlentherapie und Radioonkologie, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Frank G Zöllner
- Computerunterstützte Klinische Medizin, Mannheimer Institut für Intelligente Systeme in der Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Anne Adlung
- Computerunterstützte Klinische Medizin, Mannheimer Institut für Intelligente Systeme in der Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Dominik F Bauer
- Computerunterstützte Klinische Medizin, Mannheimer Institut für Intelligente Systeme in der Medizin, Medizinische Fakultät Mannheim, Universität Heidelberg, Mannheim, Deutschland
| | - Stefan O Schoenberg
- Klinik für Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland
| | - Dominik Nörenberg
- Klinik für Radiologie und Nuklearmedizin, Universitätsmedizin Mannheim, Medizinische Fakultät Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Deutschland.
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Sumser K, Bellizzi GG, van Rhoon GC, Paulides MM. The Potential of Adjusting Water Bolus Liquid Properties for Economic and Precise MR Thermometry Guided Radiofrequency Hyperthermia. SENSORS 2020; 20:s20102946. [PMID: 32456027 PMCID: PMC7288164 DOI: 10.3390/s20102946] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/14/2020] [Accepted: 05/21/2020] [Indexed: 11/23/2022]
Abstract
The potential of MR thermometry (MRT) fostered the development of MRI compatible radiofrequency (RF) hyperthermia devices. Such device integration creates major technological challenges and a crucial point for image quality is the water bolus (WB). The WB is located between the patient body and external sources to both couple electromagnetic energy and to cool the patient skin. However, the WB causes MRT errors and unnecessarily large field of view. In this work, we studied making the WB MRI transparent by an optimal concentration of compounds capable of modifying T2* relaxation without an impact on the efficiency of RF heating. Three different T2* reducing compounds were investigated, namely CuSO4, MnCl2, and Fe3O4. First, electromagnetic properties and T2* relaxation rates at 1.5 T were measured. Next, through multi-physics simulations, the predicted effect on the RF-power deposition pattern was evaluated and MRT precision was experimentally assessed. Our results identified 5 mM Fe3O4 solution as optimal since it does not alter the RF-power level needed and improved MRT precision from 0.39 °C to 0.09 °C. MnCl2 showed a similar MRT improvement, but caused unacceptable RF-power losses. We conclude that adding Fe3O4 has significant potential to improve RF hyperthermia treatment monitoring under MR guidance.
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Affiliation(s)
- Kemal Sumser
- Department of Radiation Oncology, Erasmus MC—Cancer Institute, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (G.G.B.); (G.C.v.R.); (M.M.P.)
- Correspondence:
| | - Gennaro G. Bellizzi
- Department of Radiation Oncology, Erasmus MC—Cancer Institute, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (G.G.B.); (G.C.v.R.); (M.M.P.)
| | - Gerard C. van Rhoon
- Department of Radiation Oncology, Erasmus MC—Cancer Institute, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (G.G.B.); (G.C.v.R.); (M.M.P.)
| | - Margarethus M. Paulides
- Department of Radiation Oncology, Erasmus MC—Cancer Institute, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (G.G.B.); (G.C.v.R.); (M.M.P.)
- EM4C&C Laboratory, Center for Care & Cure Technology Eindhoven (C3Te), Department of Electrical Engineering, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
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Anttinen M, Yli-Pietilä E, Suomi V, Mäkelä P, Sainio T, Saunavaara J, Eklund L, Blanco Sequeiros R, Taimen P, Boström PJ. Histopathological evaluation of prostate specimens after thermal ablation may be confounded by the presence of thermally-fixed cells. Int J Hyperthermia 2020; 36:915-925. [PMID: 31466481 DOI: 10.1080/02656736.2019.1652773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Purpose: Prostate cancer can be eradicated with heat exposure. However, high and rapid temperature elevations may cause thermofixation giving the appearance of viable tissue. The purpose was to characterize the immunoprofile and evaluate the viability of prostate regions with suspected thermofixation. Methods and materials: A prospective, ethics-approved and registered study (NCT03350529) enrolled six patients with MRI-visible, biopsy-concordant prostate cancer to undergo lesion-targeted MRI-guided transurethral ultrasound ablation (TULSA) followed by radical prostatectomy at 3 weeks, to evaluate the accuracy and efficacy of TULSA with whole-mount histology as a reference standard. If ambiguity about complete necrosis within the ablated region remained after hematoxylin-eosin staining, viability was assessed by immunohistochemistry. Treatment day MRI-thermometry and 3-week contrast-enhanced MRI post-TULSA were examined to assess ablation success and correlation with histopathology. Results: One patient presented with an apparently viable subregion inside the ablated area, surrounded by necrosis on H&E staining, located where temperature was highest on MRI-thermometry and tissues completely devascularized on MRI. Immunoprofile of the apparently viable tissue revealed changes in staining patterns suggesting thermofixation; the most significant evidence was the negative cytokeratin 8 staining detected with Cam5.2 antibody. A comprehensive literature review supports these observations of thermofixation with similar findings in prostate and other tissues. Conclusion: Thermally-fixed cells can sustain morphology on H&E staining. Misinterpretation of treatment failure may occur, if this phenomenon is not recognized and immunohistochemistry performed. Based on the previous literature and the current study, Cam5.2 staining for cytokeratin 8 appears to be a practical and reliable tool for distinguishing thermally-fixed from viable cells.
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Affiliation(s)
- Mikael Anttinen
- Department of Urology, Turku University Hospital , Turku , Finland
| | | | - Visa Suomi
- Department of Diagnostic Radiology, University of Turku , Turku , Finland.,Medical Imaging Centre of Southwest Finland, Turku University Hospital , Turku , Finland
| | - Pietari Mäkelä
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Teija Sainio
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Jani Saunavaara
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Lauri Eklund
- Medical Imaging Centre of Southwest Finland, Turku University Hospital , Turku , Finland.,Institute of Biomedicine, University of Turku , Turku , Finland.,Department of Pathology, Turku University Hospital , Turku , Finland
| | | | - Pekka Taimen
- Institute of Biomedicine, University of Turku , Turku , Finland.,Department of Pathology, Turku University Hospital , Turku , Finland
| | - Peter J Boström
- Department of Urology, Turku University Hospital , Turku , Finland
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Anttinen M, Mäkelä P, Suomi V, Kiviniemi A, Saunavaara J, Sainio T, Horte A, Eklund L, Taimen P, Sequeiros RB, Boström PJ. Feasibility of MRI-guided transurethral ultrasound for lesion-targeted ablation of prostate cancer. Scand J Urol 2019; 53:295-302. [PMID: 31556779 DOI: 10.1080/21681805.2019.1660707] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Background: MRI-guided transurethral ultrasound ablation (TULSA) has been evaluated for organ-confined prostate cancer (PCa). The purpose of this study was to assess the safety and toxicity, accuracy and short-term evolution of cell-death after lesion-targeted TULSA.Methods: This prospective, registered, Phase-I treat-and-3-week-resect-study enrolled six patients with MRI-visible-biopsy-concordant PCa. Lesions were targeted using TULSA with radical intent, except near neurovascular bundles (NVB). Robot-assisted-laparoscopic-prostatectomy (RALP) was performed at 3 weeks. Post-TULSA assessments included MRI (1 and 3 weeks), adverse events and quality-of-life (QoL) to 3 weeks, followed by RALP and whole-mount-histology. Treatment accuracy and demarcation of thermal injury were assessed using MRI and histology.Results: Six patients (median age = 70 years, prostate volume = 60 ml, PSA = 8.9 ng/ml) with eight biopsy-confirmed MRI-lesions (PIRADS ≥3) were TULSA-treated without complications (median sonication and MRI-times of 17 and 117 min). Foley-catheter removal was uneventful at 2-3 days. Compared to baseline, no differences in QoL were noted at 3 weeks. During follow-up, MRI-derived non-perfused-volume covered ablated targets and increased 36% by 3 weeks, correlating with necrosis-area on histology. Mean histological demarcation between complete necrosis and outer-limit-of-thermal-injury was 1.7 ± 0.4 mm. Coagulation necrosis extended to capsule except near NVB, where 3 mm safety-margins were applied. RALPs were uncomplicated and histopathology showed no viable cancer within the ablated tumor-containing target.Conclusions: Lesion-targeted TULSA demonstrates accurate and safe ablation of PCa. A significant increase of post-TULSA non-perfused-volume was observed during 3 weeks follow-up concordant with necrosis on histology. TULSA achieved coagulation necrosis of all targeted tissues. A limitation of this treat-and-resect-study-design was conservative treatment near NVB in patients scheduled for RALP.
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Affiliation(s)
- Mikael Anttinen
- Department of Urology, Turku University Hospital, Turku, Finland
| | - Pietari Mäkelä
- Department of Diagnostic Radiology, University of Turku, Turku, Finland
| | - Visa Suomi
- Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland
| | - Aida Kiviniemi
- Department of Diagnostic Radiology, University of Turku, Turku, Finland
| | - Jani Saunavaara
- Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland
| | - Teija Sainio
- Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland
| | - Antero Horte
- Department of Urology, Turku University Hospital, Turku, Finland
| | - Lauri Eklund
- Institute of Biomedicine, University of Turku, Turku, Finland.,Department of Pathology, Turku University Hospital, Turku, Finland
| | - Pekka Taimen
- Institute of Biomedicine, University of Turku, Turku, Finland.,Department of Pathology, Turku University Hospital, Turku, Finland
| | | | - Peter J Boström
- Department of Urology, Turku University Hospital, Turku, Finland
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Anthony GJ, Bader KB, Wang J, Zamora M, Ostdiek A, Antic T, Krueger S, Weiss S, Trogler WC, Blair SL, Kummel AC, Sammet S. MRI-guided transurethral insonation of silica-shell phase-shift emulsions in the prostate with an advanced navigation platform. Med Phys 2019; 46:774-788. [PMID: 30414276 PMCID: PMC6367027 DOI: 10.1002/mp.13279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 02/05/2023] Open
Abstract
PURPOSE In this study, the efficacy of transurethral prostate ablation in the presence of silica-shell ultrasound-triggered phase-shift emulsions (sUPEs) doped with MR contrast was evaluated. The influence of sUPEs on MR imaging assessment of the ablation zone was also investigated. METHODS sUPEs were doped with a magnetic resonance (MR) contrast agent, Gd2 O3 , to assess ultrasound transition. Injections of saline (sham), saline and sUPEs alone, and saline and sUPEs with Optison microbubbles were performed under guidance of a prototype interventional MRI navigation platform in a healthy canine prostate. Treatment arms were evaluated for differences in lesion size, T1 contrast, and temperature. In addition, non-perfused areas (NPAs) on dynamic contrast-enhanced (DCE) MRI, 55°C isotherms, and areas of 240 cumulative equivalent minutes at 43°C (CEM43 ) dose or greater computed from MR thermometry were measured and correlated with ablated areas indicated by histology. RESULTS For treatment arms including sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area ranged from 0.96-0.99, 0.98-0.99, and 0.91-0.99, respectively. In the absence of sUPEs, the computed correlation coefficients between the histological ablation zone and the NPA, 55°C isotherm, and 240 CEM43 area were 0.69, 0.54, and 0.50, respectively. Across all treatment arms, the areas of thermal tissue damage and NPAs were not significantly different (P = 0.47). Areas denoted by 55°C isotherms and 240 CEM43 dose boundaries were significantly larger than the areas of thermal damage, again for all treatment arms (P = 0.009 and 0.003, respectively). No significant differences in lesion size, T1 contrast, or temperature were observed between any of the treatment arms (P > 0.0167). Lesions exhibiting thermal fixation on histological analysis were present in six of nine insonations involving sUPE injections and one of five insonations involving saline sham injections. Significantly larger areas (P = 0.002), higher temperatures (P = 0.004), and more frequent ring patterns of restricted diffusion on ex vivo diffusion-weighted imaging (P = 0.005) were apparent in lesions with thermal fixation. CONCLUSIONS T1 contrast suggesting sUPE transition was not evident in sUPE treatment arms. The use of MR imaging metrics to predict prostate ablation was not diminished by the presence of sUPEs. Lesions generated in the presence of sUPEs exhibited more frequent thermal fixation, though there were no significant changes in the ablation areas when comparing arms with and without sUPEs. Thermal fixation corresponded to some qualitative imaging features.
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Affiliation(s)
| | | | - James Wang
- The University of California San DiegoSan DiegoCA92093USA
| | | | | | | | | | | | | | - Sarah L. Blair
- The University of California San DiegoSan DiegoCA92093USA
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Suomi V, Treeby B, Jaros J, Makela P, Anttinen M, Saunavaara J, Sainio T, Kiviniemi A, Blanco R. Transurethral ultrasound therapy of the prostate in the presence of calcifications: A simulation study. Med Phys 2018; 45:4793-4805. [PMID: 30216469 DOI: 10.1002/mp.13183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/24/2018] [Accepted: 09/04/2018] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Transurethral ultrasound therapy is an investigational treatment modality which could potentially be used for the localized treatment of prostate cancer. One of the limiting factors of this therapy is prostatic calcifications. These attenuate and reflect ultrasound and thus reduce the efficacy of the heating. The aim of this study is to investigate how prostatic calcifications affect therapeutic efficacy, and to identify the best sonication strategy when calcifications are present. METHODS Realistic computational models were used on clinical patient data in order to simulate different therapeutic situations with naturally occurring calcifications as well as artificial calcifications of different sizes (1-10 mm) and distances (5-15 mm). Furthermore, different sonication strategies were tested in order to deliver therapy to the untreated tissue regions behind the calcifications. RESULTS The presence of calcifications in front of the ultrasound field was found to increase the peak pressure by 100% on average while the maximum temperature only rose by 9% during a 20-s sonication. Losses in ultrasound energy were due to the relatively large acoustic impedance mismatch between the prostate tissue and the calcifications (1.63 vs 3.20 MRayl) and high attenuation coefficient (0.78 vs 2.64 dB/MHz1.1 /cm), which together left untreated tissue regions behind the calcifications. In addition, elevated temperatures were seen in the region between the transducer and the calcifications. Lower sonication frequencies (1-4 MHz) were not able to penetrate through the calcifications effectively, but longer sonication durations (20-60 s) with selective transducer elements were effective in treating the tissue regions behind the calcifications. CONCLUSIONS Prostatic calcifications limit the reach of therapeutic ultrasound treatment due to reflections and attenuation. The tissue regions behind the calcifications can possibly be treated using longer sonication durations combined with proper transducer element selection. However, caution should be taken with calcifications located close to sensitive organs such as the urethra, bladder neck, or rectal wall.
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Affiliation(s)
- Visa Suomi
- Department of Radiology, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Bradley Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jiri Jaros
- Centre of Excellence IT4Innovation, Faculty of Information Technology, Brno University of Technology, Bozetechova 1/2, 612 66, Brno, Czech Republic
| | - Pietari Makela
- Department of Radiology, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Mikael Anttinen
- Department of Urology, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Jani Saunavaara
- Department of Medical Physics, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Teija Sainio
- Department of Medical Physics, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Aida Kiviniemi
- Department of Radiology, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
| | - Roberto Blanco
- Department of Radiology, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland
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Bonekamp D, Wolf MB, Roethke MC, Pahernik S, Hadaschik BA, Hatiboglu G, Kuru TH, Popeneciu IV, Chin JL, Billia M, Relle J, Hafron J, Nandalur KR, Staruch RM, Burtnyk M, Hohenfellner M, Schlemmer HP. Twelve-month prostate volume reduction after MRI-guided transurethral ultrasound ablation of the prostate. Eur Radiol 2018; 29:299-308. [PMID: 29943185 DOI: 10.1007/s00330-018-5584-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/08/2018] [Accepted: 06/01/2018] [Indexed: 12/24/2022]
Abstract
PURPOSE To quantitatively assess 12-month prostate volume (PV) reduction based on T2-weighted MRI and immediate post-treatment contrast-enhanced MRI non-perfused volume (NPV), and to compare measurements with predictions of acute and delayed ablation volumes based on MR-thermometry (MR-t), in a central radiology review of the Phase I clinical trial of MRI-guided transurethral ultrasound ablation (TULSA) in patients with localized prostate cancer. MATERIALS AND METHODS Treatment day MRI and 12-month follow-up MRI and biopsy were available for central radiology review in 29 of 30 patients from the published institutional review board-approved, prospective, multi-centre, single-arm Phase I clinical trial of TULSA. Viable PV at 12 months was measured as the remaining PV on T2-weighted MRI, less 12-month NPV, scaled by the fraction of fibrosis in 12-month biopsy cores. Reduction of viable PV was compared to predictions based on the fraction of the prostate covered by the MR-t derived acute thermal ablation volume (ATAV, 55°C isotherm), delayed thermal ablation volume (DTAV, 240 cumulative equivalent minutes at 43°C thermal dose isocontour) and treatment-day NPV. We also report linear and volumetric comparisons between metrics. RESULTS After TULSA, the median 12-month reduction in viable PV was 88%. DTAV predicted a reduction of 90%. Treatment day NPV predicted only 53% volume reduction, and underestimated ATAV and DTAV by 36% and 51%. CONCLUSION Quantitative volumetry of the TULSA phase I MR and biopsy data identifies DTAV (240 CEM43 thermal dose boundary) as a useful predictor of viable prostate tissue reduction at 12 months. Immediate post-treatment NPV underestimates tissue ablation. KEY POINTS • MRI-guided transurethral ultrasound ablation (TULSA) achieved an 88% reduction of viable prostate tissue volume at 12 months, in excellent agreement with expectation from thermal dose calculations. • Non-perfused volume on immediate post-treatment contrast-enhanced MRI represents only 64% of the acute thermal ablation volume (ATAV), and reports only 60% (53% instead of 88% achieved) of the reduction in viable prostate tissue volume at 12 months. • MR-thermometry-based predictions of 12-month prostate volume reduction based on 240 cumulative equivalent minute thermal dose volume are in excellent agreement with reduction in viable prostate tissue volume measured on pre- and 12-month post-treatment T2w-MRI.
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Affiliation(s)
- David Bonekamp
- Department of Radiology (E010), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
| | - M B Wolf
- Department of Radiology (E010), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - M C Roethke
- Department of Radiology (E010), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - S Pahernik
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - B A Hadaschik
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - G Hatiboglu
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - T H Kuru
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - I V Popeneciu
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - J L Chin
- Department of Urology, University of Western Ontario (UWO), London Health Sciences Center, Victoria Hospital, London, ON, Canada
| | - M Billia
- Department of Urology, University of Western Ontario (UWO), London Health Sciences Center, Victoria Hospital, London, ON, Canada
| | - J Relle
- Department of Urology, Beaumont Health System, Royal Oak, MI, USA
| | - J Hafron
- Department of Urology, Beaumont Health System, Royal Oak, MI, USA
| | - K R Nandalur
- Department of Radiology, Beaumont Health System, Royal Oak, MI, USA
| | - R M Staruch
- Clinical Science, Profound Medical Inc., Toronto, ON, Canada
| | - M Burtnyk
- Clinical Science, Profound Medical Inc., Toronto, ON, Canada
| | - M Hohenfellner
- Department of Urology, University Hospital Heidelberg, Heidelberg, Germany
| | - H-P Schlemmer
- Department of Radiology (E010), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
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Skarecky D, Yu H, Linehan J, Morales B, Su MY, Fwu P, Ahlering T. Hypothermic Cooling Measured by Thermal Magnetic Resonance Imaging; Feasibility and Implications for Virtual Imaging in the Urogenital Pelvis. Urology 2017; 108:220-224. [PMID: 28733200 DOI: 10.1016/j.urology.2017.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/02/2017] [Accepted: 07/06/2017] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To study the combination of thermal magnetic resonance imaging (MRI) and novel hypothermic cooling, via an endorectal cooling balloon (ECB), to assess the effective dispersion and temperature drop in pelvic tissue to potentially reduce inflammatory cascade in surgical applications. METHODS Three male subjects, before undergoing robot-assisted radical prostatectomy, were cooled via an ECB, rendered MRI compatible for patient safety before ECB hypothermia. MRI studies were performed using a 3T scanner and included T2-weighted anatomic scan for the pelvic structures, followed by a temperature mapping scan. The sequence was performed repeatedly during the cooling experiment, whereas the phase data were collected using an integrated MR-high-intensity focused ultrasound workstation in real time. Pelvic cooling was instituted with a cooling console located outside the MRI magnet room. RESULTS The feasibility of pelvic cooling measured a temperature drop of the ECB of 20-25 degrees in real time was achieved after an initial time delay of 10-15 seconds for the ECB to cool. The thermal MRI anatomic images of the prostate and neurovascular bundle demonstrate cooling at this interface to be 10-15 degrees, and also that cooling extends into the prostate itself ~5 degrees, and disperses into the pelvic region as well. CONCLUSION An MRI-compatible ECB coupled with thermal MRI is a feasible method to assess effective hypothermic diffusion and saturation to pelvic structures. By inference, hypothermia-induced rectal cooling could potentially reduce inflammation, scarring, and fistula in radical prostatectomy, as well as other urologic tissue procedures of high-intensity focused ultrasound, external beam radiation therapy, radioactive seed implants, transurethral microwave therapy, and transurethral resection of the prostate.
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Affiliation(s)
- Douglas Skarecky
- Department of Urology, University of California Irvine, Orange, CA.
| | - Hon Yu
- Department of Radiology, University of California Irvine, Orange, CA
| | - Jennifer Linehan
- Department of Urology, John Wayne Cancer Institute, Santa Monica, CA
| | - Blanca Morales
- Department of Urology, University of California Irvine, Orange, CA
| | - Min-Ying Su
- Department of Radiology, University of California Irvine, Orange, CA
| | - Peter Fwu
- Department of Radiology, University of California Irvine, Orange, CA
| | - Thomas Ahlering
- Department of Urology, University of California Irvine, Orange, CA
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Golan R, Bernstein AN, McClure TD, Sedrakyan A, Patel NA, Parekh DJ, Marks LS, Hu JC. Partial Gland Treatment of Prostate Cancer Using High-Intensity Focused Ultrasound in the Primary and Salvage Settings: A Systematic Review. J Urol 2017; 198:1000-1009. [PMID: 28433640 DOI: 10.1016/j.juro.2017.03.137] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2017] [Indexed: 12/14/2022]
Abstract
PURPOSE Advances in prostate imaging, biopsy and ablative technologies have been accompanied by growing enthusiasm for partial gland ablation, particularly using high-intensity focused ultrasound, to treat prostate cancer. Preserving noncancerous prostate tissue and minimizing damage to the neurovascular bundles and external urethral sphincter may improve functional outcomes. MATERIALS AND METHODS A systematic review was performed following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using a combination of MeSH® terms, free text search and examination of relevant bibliographies using MEDLINE® and Embase® from the inception of each database through October 10, 2016. We excluded studies describing exclusively whole gland ablation, case reports and series where treatment was followed by immediate resection. RESULTS A total of 13 studies that enrolled 543 patients were included. Of the studies 11 were performed in the primary setting and 2 in the salvage setting. Median followup ranged from 6 months to 10.6 years. Rates of posttreatment erectile dysfunction and urinary incontinence ranged from 0% to 48% and 0% to 50%, respectively, with definitions varying by study. Overall there were 254 reported complications. Marked heterogeneity between studies limited the ability to pool results regarding functional and oncologic outcomes. A total of 76 patients (14%) subsequently received further oncologic treatment. CONCLUSIONS Early evidence suggests that partial gland ablation is a safe treatment option for men with localized disease. Longer term data are needed to evaluate oncologic efficacy and functional outcomes, and will aid in identifying the optimal candidates for therapy. Standardization of outcomes definitions will allow for better comparison between studies and among treatment modalities.
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Affiliation(s)
- Ron Golan
- Department of Urology, Weill Cornell Medical College, New York, New York
| | - Adrien N Bernstein
- Department of Urology, Weill Cornell Medical College, New York, New York
| | - Timothy D McClure
- Department of Urology, Weill Cornell Medical College, New York, New York
| | - Art Sedrakyan
- Department of Healthcare Policy and Research, Weill Cornell Medical College, New York, New York
| | - Neal A Patel
- Department of Urology, Weill Cornell Medical College, New York, New York
| | - Dipen J Parekh
- Department of Urology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Leonard S Marks
- Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Jim C Hu
- Department of Urology, Weill Cornell Medical College, New York, New York.
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Ramsay E, Mougenot C, Staruch R, Boyes A, Kazem M, Bronskill M, Foster H, Sugar L, Haider M, Klotz L, Chopra R. Evaluation of Focal Ablation of Magnetic Resonance Imaging Defined Prostate Cancer Using Magnetic Resonance Imaging Controlled Transurethral Ultrasound Therapy with Prostatectomy as the Reference Standard. J Urol 2016; 197:255-261. [PMID: 27545572 DOI: 10.1016/j.juro.2016.06.100] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2016] [Indexed: 01/02/2023]
Abstract
PURPOSE We evaluated magnetic resonance imaging controlled transurethral ultrasound therapy as a treatment for magnetic resonance imaging defined focal prostate cancer using subsequent prostatectomy and histology as the reference standard. MATERIALS AND METHODS Five men completed this pilot study, which was approved by the institutional review board. Prior to radical prostatectomy focal tumors identified by magnetic resonance imaging were treated by coagulating targeted subtotal 3-dimensional volumes of prostate tissue using magnetic resonance imaging controlled transurethral focused ultrasound. Treatment was performed with a 3 Tesla clinical magnetic resonance imaging unit combined with modified clinical planning software for high intensity focused ultrasound therapy. After prostatectomy whole mount histological sections parallel to the magnetic resonance imaging treatment planes were used to compare magnetic resonance imaging measurements with thermal damage at the cellular level and, thus, evaluate treatment and target accuracy. RESULTS Three-dimensional target volumes of 4 to 20 cc and with radii up to 35 mm from the urethra were treated successfully. Mean ± SD temperature control accuracy at the target boundary was -1.6 ± 4.8C and the mean spatial targeting accuracy achieved was -1.5 ± 2.8 mm. Mean treatment accuracy with respect to histology was -0.4 ± 1.7 mm with all index tumors falling inside the histological outer limit of thermal injury. CONCLUSIONS Magnetic resonance imaging guided transurethral ultrasound therapy is capable of generating thermal coagulation and tumor destruction in targeted 3-dimensional angular sectors out to the prostate capsule for prostate glands up to 70 cc in volume. Ultrasound parameters needed to achieve ablation at the prostate capsule were determined, providing a foundation for future studies.
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Affiliation(s)
- Elizabeth Ramsay
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | | | - Robert Staruch
- Philips Research North America, Cambridge, Massachusetts
| | - Aaron Boyes
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Mohammad Kazem
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Michael Bronskill
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Harry Foster
- Department of Anaesthesiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto
| | - Linda Sugar
- Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Masoom Haider
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Laurence Klotz
- Department of Urology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Rajiv Chopra
- Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.
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15
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Chin JL, Billia M, Relle J, Roethke MC, Popeneciu IV, Kuru TH, Hatiboglu G, Mueller-Wolf MB, Motsch J, Romagnoli C, Kassam Z, Harle CC, Hafron J, Nandalur KR, Chronik BA, Burtnyk M, Schlemmer HP, Pahernik S. Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Tissue in Patients with Localized Prostate Cancer: A Prospective Phase 1 Clinical Trial. Eur Urol 2016; 70:447-55. [PMID: 26777228 DOI: 10.1016/j.eururo.2015.12.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/16/2015] [Indexed: 02/07/2023]
Abstract
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. Thirty patients (median age: 69 yr; interquartile range [IQR]: 67-71 yr) with biopsy-proven low-risk (80%) and intermediate-risk (20%) PCa were treated and followed for 12 mo. INTERVENTION MRI-TULSA treatment was delivered with the therapeutic intent of conservative whole-gland ablation including 3-mm safety margins and 10% residual viable prostate expected around the capsule. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Primary end points were safety (adverse events) and feasibility (technical accuracy and precision of conformal thermal ablation). Exploratory outcomes included quality of life, prostate-specific antigen (PSA), and biopsy at 12 mo. RESULTS AND LIMITATIONS Median treatment time was 36min (IQR: 26-44) and prostate volume was 44ml (IQR: 38-48). Spatial control of thermal ablation was ±1.3mm on MRI thermometry. Common Terminology Criteria for Adverse Events included hematuria (43% grade [G] 1; 6.7% G2), urinary tract infections (33% G2), acute urinary retention (10% G1; 17% G2), and epididymitis (3.3% G3). There were no rectal injuries. Median pretreatment International Prostate Symptom Score 8 (IQR: 5-13) returned to 6 (IQR: 4-10) at 3 mo (mean change: -2; 95% confidence interval [CI], -4 to 1). Median pretreatment International Index of Erectile Function 13 (IQR: 6-28) recovered to 13 (IQR: 5-25) at 12 mo (mean change: -1; 95% CI, -5 to 3). Median PSA decreased 87% at 1 mo and was stable at 0.8 ng/ml (IQR: 0.6-1.1) to 12 mo. Positive biopsies showed 61% reduction in total cancer length, clinically significant disease in 9 of 29 patients (31%; 95% CI, 15-51), and any disease in 16 of 29 patients (55%; 95% CI, 36-74). CONCLUSIONS MRI-TULSA was feasible, safe, and technically precise for whole-gland prostate ablation in patients with localized PCa. Phase 1 data are sufficiently compelling to study MRI-TULSA further in a larger prospective trial with reduced safety margins. PATIENT SUMMARY We used magnetic resonance imaging-guided transurethral ultrasound to heat and ablate the prostate in men with prostate cancer. We showed that the treatment can be targeted within a narrow range (1mm) and has a well-tolerated side effect profile. A larger study is under way. TRIAL REGISTRATION NCT01686958, DRKS00005311.
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Affiliation(s)
- Joseph L Chin
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada.
| | - Michele Billia
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada
| | | | | | | | - Timur H Kuru
- University Hospital Heidelberg, Heidelberg, Germany
| | | | | | | | - Cesare Romagnoli
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada
| | - Zahra Kassam
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada
| | - Christopher C Harle
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada
| | | | | | - Blaine A Chronik
- University of Western Ontario, London Health Sciences Centre, London, ON, Canada
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16
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Prostate Focused Ultrasound Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 880:21-41. [PMID: 26486330 DOI: 10.1007/978-3-319-22536-4_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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17
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Sammet S, Partanen A, Yousuf A, Sammet CL, Ward EV, Wardrip C, Niekrasz M, Antic T, Razmaria A, Farahani K, Sokka S, Karczmar G, Oto A. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate. World J Radiol 2015; 7:521-530. [PMID: 26753067 PMCID: PMC4697126 DOI: 10.4329/wjr.v7.i12.521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 06/15/2015] [Accepted: 11/25/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer.
METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy.
RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These results indicated intact cavernous nerve functionality. In all specimens, regions of thermal ablation were limited to areas within the prostate capsule and no damage was observed in periprostatic tissues. Additionally, a visual analysis of the ablation zones on contrast-enhanced MR images acquired post ultrasound treatment correlated excellent with the ablation zones on thermal dose maps. All of the ablation zones received a consensus score of 3 (excellent) for the location and size of the correlation between the histologic ablation zone and MRI based ablation zone. During the prostatectomy and histologic examination, no damage was noted in the bladder or rectum.
CONCLUSION: Trans-urethral ultrasound treatment of the prostate with MRI guidance has potential to safely, reliably, and accurately ablate prostatic regions, while minimizing the morbidities associated with conventional whole-gland resection or therapy.
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18
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Huang CW, Sun MK, Chen BT, Shieh J, Chen CS, Chen WS. Simulation of thermal ablation by high-intensity focused ultrasound with temperature-dependent properties. ULTRASONICS SONOCHEMISTRY 2015; 27:456-465. [PMID: 26186867 DOI: 10.1016/j.ultsonch.2015.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
An integrated computational framework was developed in this study for modeling high-intensity focused ultrasound (HIFU) thermal ablation. The temperature field was obtained by solving the bioheat transfer equation (BHTE) through the finite element method; while, the thermal lesion was considered as a denatured material experiencing phase transformation and modeled with the latent heat. An equivalent attenuation coefficient, which considers the temperature-dependent properties of the target material and the ultrasound diffraction due to bubbles, was proposed in the nonlinear thermal transient analysis. Finally, a modified thermal dose formulation was proposed to predict the lesion size, shape and location. In-vitro thermal ablation experiments on transparent tissue phantoms at different energy levels were carried out to validate this computational framework. The temperature histories and lesion areas from the proposed model show good correlation with those from the in-vitro experiments.
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Affiliation(s)
- C W Huang
- Department of Civil Engineering, Chung Yuan Christian University, Taoyuan, Taiwan.
| | - M K Sun
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan
| | - B T Chen
- Department of Civil Engineering, Chung Yuan Christian University, Taoyuan, Taiwan
| | - J Shieh
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
| | - C S Chen
- Department of Civil Engineering, National Taiwan University, Taipei, Taiwan
| | - W S Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan.
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Abstract
Advances in medical imaging have enabled the development of new minimally and completely noninvasive therapies that produce a desired biological effect in a target, such as a tumor, with minimal damage to the surrounding tissue. One means of noninvasively achieving bioeffects in tissue is the use of ultrasound to generate heat. Specialized ultrasound transducers can be used to generate focal regions of heating non invasively, without inserting anything into the body or affecting the tissue outside the target region. Ultrasound thermal therapy can be used with magnetic resonance (MR) imaging (MRI) guidance and MRI temperature feedback to automatically control temperature distributions during heating, producing accurate thermal lesions, or maintaining optimal conditions to enhance drug delivery.
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20
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Schmitt A, Mougenot C, Chopra R. Spatiotemporal filtering of MR-temperature artifacts arising from bowel motion during transurethral MR-HIFU. Med Phys 2015; 41:113302. [PMID: 25370670 DOI: 10.1118/1.4897382] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Transurethral MR-HIFU is a minimally invasive image-guided treatment for localized prostate cancer that enables precise targeting of tissue within the gland. The treatment is performed within a clinical MRI to obtain real-time MR thermometry used as an active feedback to control the spatial heating pattern in the prostate and to monitor for potential damage to surrounding tissues. This requires that the MR thermometry measurements are an accurate representation of the true tissue temperature. The proton resonance frequency shift thermometry method used is sensitive to tissue motion and changes in the local magnetic susceptibility that can be caused by the motion of air bubbles in the rectum, which can impact the performance of transurethral MR-HIFU in these regions of the gland. METHODS A method is proposed for filtering of temperature artifacts based on the temporal variance of the temperature, using empirical and dynamic positional knowledge of the ultrasonic heating beam, and an estimation of the measurement noise. A two-step correction strategy is introduced which eliminates artifact-detected temperature variations while keeping the noise level low through spatial averaging. RESULTS The filter has been evaluated by postprocessing data from five human transurethral ultrasound treatments. The two-step correction process led to reduced final temperature standard deviation in the prostate and rectum areas where the artifact was located, without negatively affecting areas distal to the artifact. The performance of the filter was also found to be consistent across all six of the data sets evaluated. The evaluation of the detection criterion parameter M determined that a value of M = 3 achieves a conservative filter with minimal loss of spatial resolution during the process. CONCLUSIONS The filter was able to remove most artifacts due to the presence of moving air bubbles in the rectum during transurethral MR-HIFU. A quantitative estimation of the filter capabilities shows a systematic improvement in the standard deviation of the corrected temperature maps in the rectum zone as well as in the entire acquired slice.
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Affiliation(s)
- Alain Schmitt
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada
| | - Charles Mougenot
- Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3, Canada
| | - Rajiv Chopra
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canadaand Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9061
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21
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Burtnyk M, Hill T, Cadieux-Pitre H, Welch I. Magnetic Resonance Image Guided Transurethral Ultrasound Prostate Ablation: A Preclinical Safety and Feasibility Study with 28-Day Followup. J Urol 2015; 193:1669-75. [DOI: 10.1016/j.juro.2014.11.089] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Mathieu Burtnyk
- Profound Medical, Inc., Toronto, Ontario, Canada
- Animal Care and Veterinary Services, Western University (TH, HC-P, IW), London, Ontario, Canada
| | - Tracy Hill
- Profound Medical, Inc., Toronto, Ontario, Canada
- Animal Care and Veterinary Services, Western University (TH, HC-P, IW), London, Ontario, Canada
| | - Heather Cadieux-Pitre
- Profound Medical, Inc., Toronto, Ontario, Canada
- Animal Care and Veterinary Services, Western University (TH, HC-P, IW), London, Ontario, Canada
| | - Ian Welch
- Profound Medical, Inc., Toronto, Ontario, Canada
- Animal Care and Veterinary Services, Western University (TH, HC-P, IW), London, Ontario, Canada
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22
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Yiallouras C, Ioannides K, Dadakova T, Pavlina M, Bock M, Damianou C. Three-axis MR-conditional robot for high-intensity focused ultrasound for treating prostate diseases transrectally. J Ther Ultrasound 2015; 3:2. [PMID: 25657846 PMCID: PMC4318438 DOI: 10.1186/s40349-014-0023-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A prototype magnetic resonance image (MRI)-conditional robot was developed for navigating a high-intensity focused ultrasound (HIFU) system in order to treat prostate cancer transrectally. MATERIALS AND METHODS The developed robotic device utilizes three PC-controlled axes: a linear axis for motion along the rectum, an angular axis for rotation in the rectum, and a linear axis to lift the robot up and down. Experiments with the system were performed in a 1.5-T MRI system using gel phantoms. RESULT The robot was successfully operated in a 1.5-T clinical MRI system. The effect of piezoelectric motors and optical encoders was quantified based on the reduction of signal to noise ratio. Discrete and overlapping lesions were created accurately by moving the HIFU transducer with the robotic device. CONCLUSION An MRI-conditional HIFU robot was developed which can create controlled thermal lesions under MRI guidance. The intention is to use this robot transrectally in the future for the treatment of prostate cancer.
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Affiliation(s)
- Christos Yiallouras
- />MEDSONIC LTD, Limassol, Cyprus
- />Biomedical Engineering Department, City University, London, UK
| | | | - Tetiana Dadakova
- />Radiology—Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Matt Pavlina
- />Radiology—Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Michael Bock
- />Radiology—Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Christakis Damianou
- />MEDSONIC LTD, Limassol, Cyprus
- />Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
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Yiallouras C, Damianou C. Review of MRI positioning devices for guiding focused ultrasound systems. Int J Med Robot 2014; 11:247-55. [PMID: 25045075 DOI: 10.1002/rcs.1601] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 11/10/2022]
Abstract
BACKGROUND This article contains a review of positioning devices that are currently used in the area of magnetic resonance imaging (MRI) guided focused ultrasound surgery (MRgFUS). METHODS The paper includes an extensive review of literature published since the first prototype system was invented in 1991. RESULTS The technology has grown into a fast developing area with application to any organ accessible to ultrasound. The initial design operated using hydraulic principles, while the latest technology incorporates piezoelectric motors. Although, in the beginning there were fears regarding MRI safety, during recent years, the deployment of MR-safe positioning devices in FUS has become routine. Many of these positioning devices are now undergoing testing in clinical trials. CONCLUSION Existing MRgFUS systems have been utilized mostly in oncology (fibroids, brain, liver, kidney, bone, pancreas, eye, thyroid, and prostate). It is anticipated that, in the near future, there will be a positioning device for every organ that is accessible by focused ultrasound.
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Affiliation(s)
- C Yiallouras
- Department of Bioengineering, City University, London, UK.,R&D, MEDSONIC LTD, Limassol, Cyprus
| | - C Damianou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus.,R&D, MEDSONIC LTD, Limassol, Cyprus
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Wu X, Zhang F, Chen R, Zheng W, Yang X. Recent advances in imaging-guided interventions for prostate cancers. Cancer Lett 2014; 349:114-9. [PMID: 24769076 DOI: 10.1016/j.canlet.2014.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 04/02/2014] [Accepted: 04/16/2014] [Indexed: 11/26/2022]
Abstract
The numbers of patients diagnosed with prostate cancers is increasing due to the widespread application of prostate-specific antigen screening and subsequent prostate biopsies. The methods of systemic administration of therapeutics are not target-specific and thus cannot efficiently destroy prostate tumour cells while simultaneously sparing the surrounding normal tissues and organs. Recent advances in imaging-guided minimally invasive therapeutic techniques offer considerable potential for the effective management of prostate cancers. An objective understanding of the feasibility, effectiveness, morbidity, and deficiencies of these interventional techniques is essential for both clinical practice and scientific progress. This review presents the recent advances in imaging-guided interventional techniques for the diagnosis and treatment of prostate cancers.
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Affiliation(s)
- Xia Wu
- Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, 3 East Qingchun Road, Hangzhou 310016, China; Image-Guided Bio-Molecular Intervention Research and Section of Vascular & Interventional Radiology, Department of Radiology, University of Washington School of Medicine, 850 Republican Street, Seattle, WA 98109, USA.
| | - Feng Zhang
- Image-Guided Bio-Molecular Intervention Research and Section of Vascular & Interventional Radiology, Department of Radiology, University of Washington School of Medicine, 850 Republican Street, Seattle, WA 98109, USA.
| | - Ran Chen
- Department of Diagnostic Ultrasound and Echocardiography, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University,3 East Qingchun Road, Hangzhou 310016, China.
| | - Weiliang Zheng
- Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, 3 East Qingchun Road, Hangzhou 310016, China.
| | - Xiaoming Yang
- Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, 3 East Qingchun Road, Hangzhou 310016, China; Image-Guided Bio-Molecular Intervention Research and Section of Vascular & Interventional Radiology, Department of Radiology, University of Washington School of Medicine, 850 Republican Street, Seattle, WA 98109, USA.
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Rata M, Birlea V, Murillo A, Paquet C, Cotton F, Salomir R. Endoluminal MR-guided ultrasonic applicator embedding cylindrical phased-array transducers and opposed-solenoid detection coil. Magn Reson Med 2014; 73:417-26. [PMID: 24478117 DOI: 10.1002/mrm.25099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/18/2013] [Accepted: 12/07/2013] [Indexed: 12/20/2022]
Abstract
PURPOSE MR-guided high-intensity contact ultrasound (HICU) was suggested as an alternative therapy for esophageal and rectal cancer. To offer high-quality MR guidance, two prototypes of receive-only opposed-solenoid coil were integrated with 64-element cylindrical phased-array ultrasound transducers (rectal/esophageal). METHODS The design of integrated coils took into account the transducer geometry (360° acoustic window within endoluminal space). The rectal coil was sealed on a plastic support and placed reversibly on the transducer head. The esophageal coil was fully embedded within the transducer head, resulting in one indivisible device. Comparison of integrated versus external coils was performed on a clinical 1.5T scanner. RESULTS The integrated coils showed higher sensitivity compared with the standard extracorporeal coil with factors of up to 7.5 (rectal applicator) and 3.3 (esophageal applicator). High-resolution MR images for both anatomy (voxel 0.4 × 0.4 × 5 mm(3)) and thermometry (voxel 0.75 × 0.75 × 8 mm(3), 2 s/image) were acquired in vivo with the rectal endoscopic device. The temperature feedback loop accurately controlled multiple control points over the region of interest. CONCLUSION This study showed significant improvement of MR data quality using endoluminal integrated coils versus standard external coil. Inframillimeter spatial resolution and accurate feedback control of MR-guided HICU thermotherapy were achieved.
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Affiliation(s)
- Mihaela Rata
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Université de Lyon, Université Claude Bernard Lyon 1, Lyon, F-69003, France
| | - Vlad Birlea
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Babes-Bolyai University, Faculty of Physics, Cluj-Napoca, Romania
| | - Adriana Murillo
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France
| | - Christian Paquet
- Université de Lyon, VetAgro Sup, EA 4174, Marcy l'Etoile, F-69280, France
| | - François Cotton
- Université de Lyon, Université Claude Bernard Lyon 1, Lyon, F-69003, France.,MR Unit, Radiology Department, Lyon Sud University Hospital, Hospices Civils de Lyon, Pierre-Bénite, F-69495, France
| | - Rares Salomir
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Radiology Department, Faculty of Medicine, University of Geneva, Geneva, CH-1211, Switzerland
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Applicators for magnetic resonance-guided ultrasonic ablation of benign prostatic hyperplasia. Invest Radiol 2014; 48:387-94. [PMID: 23462673 DOI: 10.1097/rli.0b013e31827fe91e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The aims of this study were to evaluate in a canine model applicators designed for ablation of human benign prostatic hyperplasia (BPH) in vivo under magnetic resonance imaging (MRI) guidance, including magnetic resonance thermal imaging (MRTI), determine the ability of MRI techniques to visualize ablative changes in prostate, and evaluate the acute and longer term histologic appearances of prostate tissue ablated during these studies. MATERIALS AND METHODS An MRI-compatible transurethral device incorporating a tubular transducer array with dual 120° sectors was used to ablate canine prostate tissue in vivo, in zones similar to regions of human BPH (enlarged transition zones). Magnetic resonance thermal imaging was used for monitoring of ablation in a 3-T environment, and postablation MRIs were performed to determine the visibility of ablated regions. Three canine prostates were ablated in acute studies, and 2 animals were rescanned before killing at 31 days postablation. Acute and chronic appearances of ablated prostate tissue were evaluated histologically and were correlated with the MRTI and postablation MRI scans. RESULTS It was possible to ablate regions similar in size to enlarged transition zone in human BPH in 6 to 18 minutes. Regions of acute ablation showed a central "heat-fixed" region surrounded by a region of more obvious necrosis with complete disruption of tissue architecture. After 31 days, ablated regions demonstrated complete apparent resorption of ablated tissue with formation of cystic regions containing fluid. The inherent cooling of the urethra using the technique resulted in complete urethral preservation in all cases. CONCLUSIONS Prostatic ablation of zones of size and shape corresponding to human BPH is possible using appropriate transurethral applicators using MRTI, and ablated tissue may be depicted clearly in contrast-enhanced magnetic resonance images. The ability accurately to monitor prostate tissue heating, the apparent resorption of ablated regions over 1 month, and the inherent urethral preservation suggest that the magnetic resonance-guided techniques described are highly promising for the in vivo ablation of symptomatic human BPH.
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Yiallouras C, Mylonas N, Damianou C. MRI-compatible positioning device for guiding a focused ultrasound system for transrectal treatment of prostate cancer. Int J Comput Assist Radiol Surg 2013; 9:745-53. [DOI: 10.1007/s11548-013-0964-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 11/12/2013] [Indexed: 10/25/2022]
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Partanen A, Yerram NK, Trivedi H, Dreher MR, Oila J, Hoang AN, Volkin D, Nix J, Turkbey B, Bernardo M, Haines DC, Benjamin CJ, Linehan WM, Choyke P, Wood BJ, Ehnholm GJ, Venkatesan AM, Pinto PA. Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy of the prostate: a preclinical study with radiological and pathological correlation using customised MRI-based moulds. BJU Int 2013; 112:508-16. [PMID: 23746198 DOI: 10.1111/bju.12126] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To characterise the feasibility and safety of a novel transurethral ultrasound (US)-therapy device combined with real-time multi-plane magnetic resonance imaging (MRI)-based temperature monitoring and temperature feedback control, to enable spatiotemporally precise regional ablation of simulated prostate gland lesions in a preclinical canine model. To correlate ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. MATERIALS AND METHODS Three dogs were treated with three targeted ablations each, using a prototype MRI-guided transurethral US-therapy system (Philips Healthcare, Vantaa, Finland). MRI provided images for treatment planning, guidance, real-time multi-planar thermometry, as well as post-treatment evaluation of efficacy. After treatment, specimens underwent histopathological analysis to determine the extent of necrosis and cell viability. Statistical analyses (Pearson's correlation, Student's t-test) were used to evaluate the correlation between ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. RESULTS MRI combined with a transurethral US-therapy device enabled multi-planar temperature monitoring at the target as well as in surrounding tissues, allowing for safe, targeted, and controlled ablations of prescribed lesions. Ablated volumes measured by cumulative thermal dose positively correlated with volumes determined by histopathological analysis (r(2) 0.83, P < 0.001). Post-procedural contrast-enhanced and diffusion-weighted MRI showed a positive correlation with non-viable areas on histopathological analysis (r(2) 0.89, P < 0.001, and r(2) 0.91, P = 0.003, respectively). Additionally, there was a positive correlation between ablated volumes according to cumulative thermal dose and volumes identified on post-procedural contrast-enhanced MRI (r(2) 0.77, P < 0.01). There was no difference in mean ablation volumes assessed with the various analysis methods (P > 0.05, Student's t-test). CONCLUSIONS MRI-guided transurethral US therapy enabled safe and targeted ablations of prescribed lesions in a preclinical canine prostate model. Ablation volumes were reliably predicted by intra- and post-procedural imaging. Clinical studies are needed to confirm the feasibility, safety, oncological control, and functional outcomes of this therapy in patients in whom focal therapy is indicated.
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Affiliation(s)
- Ari Partanen
- Philips Healthcare, Cleveland, OH; Department of Physics, University of Helsinki, Helsinki, Finland
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Prakash P, Salgaonkar VA, Diederich CJ. Modelling of endoluminal and interstitial ultrasound hyperthermia and thermal ablation: applications for device design, feedback control and treatment planning. Int J Hyperthermia 2013; 29:296-307. [PMID: 23738697 PMCID: PMC4087028 DOI: 10.3109/02656736.2013.800998] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Endoluminal and catheter-based ultrasound applicators are currently under development and are in clinical use for minimally invasive hyperthermia and thermal ablation of various tissue targets. Computational models play a critical role in device design and optimisation, assessment of therapeutic feasibility and safety, devising treatment monitoring and feedback control strategies, and performing patient-specific treatment planning with this technology. The critical aspects of theoretical modelling, applied specifically to endoluminal and interstitial ultrasound thermotherapy, are reviewed. Principles and practical techniques for modeling acoustic energy deposition, bioheat transfer, thermal tissue damage, and dynamic changes in the physical and physiological state of tissue are reviewed. The integration of these models and applications of simulation techniques in identification of device design parameters, development of real time feedback-control platforms, assessing the quality and safety of treatment delivery strategies, and optimisation of inverse treatment plans are presented.
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Affiliation(s)
- Punit Prakash
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506, USA.
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Todd N, Prakash J, Odéen H, de Bever J, Payne A, Yalavarthy P, Parker DL. Toward real-time availability of 3D temperature maps created with temporally constrained reconstruction. Magn Reson Med 2013; 71:1394-404. [PMID: 23670981 DOI: 10.1002/mrm.24783] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/11/2013] [Accepted: 04/03/2013] [Indexed: 11/05/2022]
Abstract
PURPOSE To extend the previously developed temporally constrained reconstruction (TCR) algorithm to allow for real-time availability of three-dimensional (3D) temperature maps capable of monitoring MR-guided high intensity focused ultrasound applications. METHODS A real-time TCR (RT-TCR) algorithm is developed that only uses current and previously acquired undersampled k-space data from a 3D segmented EPI pulse sequence, with the image reconstruction done in a graphics processing unit implementation to overcome computation burden. Simulated and experimental data sets of HIFU heating are used to evaluate the performance of the RT-TCR algorithm. RESULTS The simulation studies demonstrate that the RT-TCR algorithm has subsecond reconstruction time and can accurately measure HIFU-induced temperature rises of 20°C in 15 s for 3D volumes of 16 slices (RMSE = 0.1°C), 24 slices (RMSE = 0.2°C), and 32 slices (RMSE = 0.3°C). Experimental results in ex vivo porcine muscle demonstrate that the RT-TCR approach can reconstruct temperature maps with 192 × 162 × 66 mm 3D volume coverage, 1.5 × 1.5 × 3.0 mm resolution, and 1.2-s scan time with an accuracy of ±0.5°C. CONCLUSION The RT-TCR algorithm offers an approach to obtaining large coverage 3D temperature maps in real-time for monitoring MR-guided high intensity focused ultrasound treatments.
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Affiliation(s)
- Nick Todd
- Department of Radiology, University of Utah, Salt Lake City, Utah, USA
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Chopra R, Colquhoun A, Burtnyk M, N'djin WA, Kobelevskiy I, Boyes A, Siddiqui K, Foster H, Sugar L, Haider MA, Bronskill M, Klotz L. MR imaging-controlled transurethral ultrasound therapy for conformal treatment of prostate tissue: initial feasibility in humans. Radiology 2012; 265:303-13. [PMID: 22929332 DOI: 10.1148/radiol.12112263] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
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. This phase 0 feasibility and safety study is the first evaluation in humans. Transurethral ultrasound therapy was performed with the patient under spinal anesthesia by using a clinical 1.5-T MR unit. Patients then underwent radical prostatectomy, and the resected gland was sliced in the plane of treatment to compare the MR imaging measurements with the pattern of thermal damage. The overall procedure time and coagulation rate were measured. In addition, the spatial targeting accuracy was evaluated, as was the thermal history along the thermal damage boundaries in the gland. RESULTS The average procedure time was 3 hours, with 2 or fewer hours spent in the MR unit. The treatment was well tolerated by all patients, and a temperature uncertainty of less than 2°C was observed in the treatments. The mean temperature and thermal dose measured along the boundary of thermal coagulation were 52.3°C±2.1 and 3457 (cumulative equivalent minutes at 43°C)±5580, respectively. The mean treatment rate was 0.5 mL/min, and a spatial targeting accuracy of -1.0 mm±2.6 was achieved. CONCLUSION MR imaging-controlled transurethral ultrasound therapy is feasible, safe, and well tolerated. This technology could be an attractive approach for whole-gland or focal therapy.
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Affiliation(s)
- Rajiv Chopra
- Imaging Research, Sunnybrook Research Institute, 2075 Bayview Ave, Room C713, Toronto, ON, Canada M4N 3M5.
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Zini C, Hipp E, Thomas S, Napoli A, Catalano C, Oto A. Ultrasound- and MR-guided focused ultrasound surgery for prostate cancer. World J Radiol 2012; 4:247-52. [PMID: 22778876 PMCID: PMC3391669 DOI: 10.4329/wjr.v4.i6.247] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/15/2012] [Accepted: 05/22/2012] [Indexed: 02/06/2023] Open
Abstract
Prostate cancer (PC) is one of the most frequently diagnosed cancers in men. There are a number of treatment options for PC with a different therapeutic approach between USA and Europe. Radical prostatectomy is one of the most used therapies but focal gland therapy is an emerging approach, especially for localized tumors. In this scenario, high intensity focused ultrasound (HIFU) has been incorporated in certain medical association guidelines. HIFU has been employed for about 10 years especially for localized PC. Results are promising with a 5-year biochemical survival rate ranging from 45% to 84%. Collateral events are rare and HIFU retreatment is not common. Magnetic resonance guided focused ultrasound surgery (MRgFUS) was recently presented as a method for ablation with focused ultrasound under magnetic resonance imaging guidance. It has the advantage of improved targeting and real time temperature monitoring but only a few studies have been conducted with human patients. The aim of this review is to describe the current status of HIFU and MRgFUS in the therapy of PC.
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Mocikova I, Babela J, Balaz V. Prostate cancer - the role of magnetic resonance imaging. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2012; 156:103-7. [DOI: 10.5507/bp.2012.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Hofstetter LW, Yeo DTB, Dixon WT, Kempf JG, Davis CE, Foo TK. Fat-referenced MR thermometry in the breast and prostate using IDEAL. J Magn Reson Imaging 2012; 36:722-32. [PMID: 22581513 DOI: 10.1002/jmri.23692] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 04/02/2012] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To demonstrate a three-echo fat-referenced MR thermometry technique that estimates and corrects for time-varying phase disturbances in heterogeneous tissues. MATERIALS AND METHODS Fat protons do not exhibit a temperature-dependent frequency shift. Fat-referenced thermometry methods exploit this insensitivity and use the signal from fat to measure and correct for magnetic field disturbances. In this study, we present a fat-referenced method that uses interpolation of the fat signal to correct for phase disturbances in fat free regions. Phantom and ex vivo tissue cool-down experiments were performed to evaluate the accuracy of this method in the absence of motion. Non-heated in vivo imaging of the breast and prostate was performed to demonstrate measurement robustness in the presence of systemic and motion-induced field disturbances. Measurement accuracy of the method was compared to conventional proton resonance frequency shift MR thermometry. RESULTS In the ex vivo porcine tissue experiment, maximum measurement error of the fat-referenced method was reduced 42% from 3.3 to 1.9°C when compared to conventional MR thermometry. In the breasts, measurement errors were reduced by up to 70% from 6.4 to 1.9°C. CONCLUSION Ex vivo and in vivo results show that the proposed method reduces measurement errors in the heterogeneous tissue experiments when compared to conventional MR thermometry.
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Prakash P, Diederich CJ. Considerations for theoretical modelling of thermal ablation with catheter-based ultrasonic sources: implications for treatment planning, monitoring and control. Int J Hyperthermia 2012; 28:69-86. [PMID: 22235787 DOI: 10.3109/02656736.2011.630337] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
PURPOSE To determine the impact of including dynamic changes in tissue physical properties during heating on feedback controlled thermal ablation with catheter-based ultrasound. Additionally, we compared the impact of several indicators of thermal damage on predicted extents of ablation zones for planning and monitoring ablations with this modality. METHODS A 3D model of ultrasound ablation with interstitial and transurethral applicators incorporating temperature-based feedback control was used to simulate thermal ablations in prostate and liver tissue. We investigated five coupled models of heat dependent changes in tissue acoustic attenuation/absorption and blood perfusion of varying degrees of complexity. Dimensions of the ablation zone were computed using temperature, thermal dose, and Arrhenius thermal damage indicators of coagulative necrosis. A comparison of the predictions by each of these models was illustrated on a patient-specific anatomy in the treatment planning setting. RESULTS Models including dynamic changes in blood perfusion and acoustic attenuation as a function of thermal dose/damage predicted near-identical ablation zone volumes (maximum variation < 2.5%). Accounting for dynamic acoustic attenuation appeared to play a critical role in estimating ablation zone size, as models using constant values for acoustic attenuation predicted ablation zone volumes up to 50% larger or 47% smaller in liver and prostate tissue, respectively. Thermal dose (t(43) ≥ 240 min) and thermal damage (Ω ≥ 4.6) thresholds for coagulative necrosis are in good agreement for all heating durations, temperature thresholds in the range of 54°C for short (<5 min) duration ablations and 50°C for long (15 min) ablations may serve as surrogates for determination of the outer treatment boundary. CONCLUSIONS Accounting for dynamic changes in acoustic attenuation/absorption appeared to play a critical role in predicted extents of ablation zones. For typical 5-15 min ablations with this modality, thermal dose and Arrhenius damage measures of ablation zone dimensions are in good agreement, while appropriately selected temperature thresholds provide a computationally cheaper surrogate.
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Affiliation(s)
- Punit Prakash
- Thermal Therapy Research Group, Department of Radiation Oncology, University of California-San Francisco, CA 94143, USA.
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N'djin WA, Burtnyk M, Bronskill M, Chopra R. Investigation of power and frequency for 3D conformal MRI-controlled transurethral ultrasound therapy with a dual frequency multi-element transducer. Int J Hyperthermia 2012; 28:87-104. [PMID: 22235788 DOI: 10.3109/02656736.2011.622343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
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. Simulations and validation experiments in gel phantoms were used, with a collection of nine 3D realistic target prostate boundaries obtained from previous preclinical studies, where multi-slice MR images were acquired with the transurethral device in place. Acoustic power and rotation rate were varied based on temperature feedback at the prostate boundary. Maximum acoustic power and rotation rate were optimised interdependently, as a function of prostate radius and transducer operating frequency. The concept of dual frequency transducers was studied, using the fundamental frequency or the third harmonic component depending on the prostate radius. Numerical modelling enabled assessment of the effects of several acoustic parameters on treatment outcomes. The range of treatable prostate radii extended with increasing power, and tended to narrow with decreasing frequency. Reducing the frequency from 8 MHz to 4 MHz or increasing the surface acoustic power from 10 to 20 W/cm(2) led to treatment times shorter by up to 50% under appropriate conditions. A dual frequency configuration of 4/12 MHz with 20 W/cm(2) ultrasound intensity exposure can treat entire prostates up to 40 cm(3) in volume within 30 min. The interdependence between power and frequency may, however, require integrating multi-parametric functions in the controller for future optimisations.
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Affiliation(s)
- William Apoutou N'djin
- Imaging Research, Sunnybrook Health Sciences Centre, and Department of Medical Biophysics, University of Toronto, Ontario, Canada.
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Miller DL, Smith NB, Bailey MR, Czarnota GJ, Hynynen K, Makin IRS. Overview of therapeutic ultrasound applications and safety considerations. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2012; 31:623-34. [PMID: 22441920 PMCID: PMC3810427 DOI: 10.7863/jum.2012.31.4.623] [Citation(s) in RCA: 331] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Applications of ultrasound in medicine for therapeutic purposes have been accepted and beneficial uses of ultrasonic biological effects for many years. Low-power ultrasound of about 1 MHz has been widely applied since the 1950s for physical therapy in conditions such as tendinitis and bursitis. In the 1980s, high-pressure-amplitude shock waves came into use for mechanically resolving kidney stones, and "lithotripsy" rapidly replaced surgery as the most frequent treatment choice. The use of ultrasonic energy for therapy continues to expand, and approved applications now include uterine fibroid ablation, cataract removal (phacoemulsification), surgical tissue cutting and hemostasis, transdermal drug delivery, and bone fracture healing, among others. Undesirable bioeffects can occur, including burns from thermal-based therapies and severe hemorrhage from mechanical-based therapies (eg, lithotripsy). In all of these therapeutic applications of ultrasound bioeffects, standardization, ultrasound dosimetry, benefits assurance, and side-effect risk minimization must be carefully considered to ensure an optimal benefit to risk ratio for the patient. Therapeutic ultrasound typically has well-defined benefits and risks and therefore presents a manageable safety problem to the clinician. However, safety information can be scattered, confusing, or subject to commercial conflicts of interest. Of paramount importance for managing this problem is the communication of practical safety information by authoritative groups, such as the American Institute of Ultrasound in Medicine, to the medical ultrasound community. In this overview, the Bioeffects Committee of the American Institute of Ultrasound in Medicine outlines the wide range of therapeutic ultrasound methods, which are in clinical use or under study, and provides general guidance for ensuring therapeutic ultrasound safety.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan, 3240A Medical Science Building I, 1301 Catherine St, Ann Arbor, MI 48109-5667, USA.
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Langley J, Potter W, Phipps C, Huang F, Zhao Q. A self-reference PRF-shift MR thermometry method utilizing the phase gradient. Phys Med Biol 2011; 56:N307-20. [DOI: 10.1088/0031-9155/56/24/n02] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Li Y, Zeng Y, Mooney SM, Yin B, Mizokami A, Namiki M, Getzenberg RH. Resistance to paclitaxel increases the sensitivity to other microenvironmental stresses in prostate cancer cells. J Cell Biochem 2011; 112:2125-37. [PMID: 21465536 DOI: 10.1002/jcb.23134] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The microenvironment is central to many aspects of cancer pathobiology and has been proposed to play a role in the development of cancer cell resistance to therapy. To examine the response to microenvironmental conditions, two paclitaxel resistant prostate cancer (PCa) cell lines (stable and reversible) and one reversible heat resistant cell line were studied. In comparison to their parental cell lines, both paclitaxel resistant cell lines (stable and reversible) were more sensitive to microenvironmental heat, potentially yielding a synergistic therapeutic opportunity. In the two phenotypic cells repopulated after acute heat or paclitaxel treatments, there was an inverse correlation between paclitaxel and heat resistance: resistance to paclitaxel imparted sensitivity to heat; resistance to heat imparted sensitivity to paclitaxel. These studies indicate that as cancer cells evolve resistance to single microenvironmental stress they may be more sensitive to others, perhaps allowing us to design new approaches for PCa therapy.
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Affiliation(s)
- Youqiang Li
- Department of Urology, James Buchanan Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA
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Da Rosa MR, Trachtenberg J, Chopra R, Haider MA. Early experience in MRI-guided therapies of prostate cancer: HIFU, laser and photodynamic treatment. Cancer Imaging 2011; 11 Spec No A:S3-8. [PMID: 22187023 PMCID: PMC3266567 DOI: 10.1102/1470-7330.2011.9003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Prostate cancer screening has resulted in earlier diagnosis with lower-grade disease, leading to over-detection and over-treatment in a significant number of patients. Current whole-gland radical treatments are associated with significant rates of morbidity. The high prevalence of low-risk disease together with an inability to accurately identify those men harboring more aggressive cancers has led to tremendous research in low-morbidity focal therapies for prostate cancer. This review summarizes the early experiences with focal therapy with emphasis on early applications of laser, high-intensity focuses ultrasound, and photodynamic approaches.
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Affiliation(s)
- M R Da Rosa
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
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Clarke GM, Peressotti C, Constantinou P, Hosseinzadeh D, Martel A, Yaffe MJ. Increasing specimen coverage using digital whole-mount breast pathology: Implementation, clinical feasibility and application in research. Comput Med Imaging Graph 2011; 35:531-41. [DOI: 10.1016/j.compmedimag.2011.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 03/13/2011] [Accepted: 05/03/2011] [Indexed: 01/16/2023]
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Yarmolenko PS, Moon EJ, Landon C, Manzoor A, Hochman DW, Viglianti BL, Dewhirst MW. Thresholds for thermal damage to normal tissues: an update. Int J Hyperthermia 2011; 27:320-43. [PMID: 21591897 DOI: 10.3109/02656736.2010.534527] [Citation(s) in RCA: 416] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The purpose of this review is to summarise a literature survey on thermal thresholds for tissue damage. This review covers published literature for the consecutive years from 2002-2009. The first review on this subject was published in 2003. It included an extensive discussion of how to use thermal dosimetric principles to normalise all time-temperature data histories to a common format. This review utilises those same principles to address sensitivity of a variety of tissues, but with particular emphasis on brain and testis. The review includes new data on tissues that were not included in the original review. Several important observations have come from this review. First, a large proportion of the papers examined for this review were discarded because time-temperature history at the site of thermal damage assessment was not recorded. It is strongly recommended that future research on this subject include such data. Second, very little data is available examining chronic consequences of thermal exposure. On a related point, the time of assessment of damage after exposure is critically important for assessing whether damage is transient or permanent. Additionally, virtually no data are available for repeated thermal exposures which may occur in certain recreational or occupational activities. For purposes of regulatory guidelines, both acute and lasting effects of thermal damage should be considered.
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Affiliation(s)
- Pavel S Yarmolenko
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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Lindner U, Lawrentschuk N, Schatloff O, Trachtenberg J, Lindner A. Evolution from active surveillance to focal therapy in the management of prostate cancer. Future Oncol 2011; 7:775-87. [DOI: 10.2217/fon.11.51] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Organ-preserving therapies are widely accepted in many facets of medicine and, more recently, in oncology. For example, partial nephrectomy is now accepted as a preferred alternative over radical nephrectomy for small (up to 4 cm or T1) tumors. Focal therapy (FT) is another organ-preserving strategy applying energy (cryotherapy, laser ablation and/or high-intensity focused ultrasound) to destroy tumors while leaving the majority of the organ, surrounding tissue and structures unscathed and functional. Owing to the perceived multifocality of prostate cancer (PCa) technology limitations, in the past PCa was not considered suitable for FT. However, with the rise of active surveillance for the management of low-risk PCa in carefully selected patients, FT is emerging as an alternative. This is owing to technology improvements in imaging and energy-delivery systems to ablate tissue, as well as the realization that many men and clinicians still desire tumor control. With the postulated ability to ablate tumors with minimal morbidity, FT may have found a role in the management of PCa; the aim of FT a being long-term cancer control without the morbidity associated with radical therapies. Data for FT in PCa have been derived from case series and small Phase I trials, with larger cohort studies with longer follow-up having only just commenced. More data from large trials on the safety and efficacy of FT are required before this approach can be recommended in men with PCa. Importantly, studies must confirm that no viable cancer cells remain in the region of ablation. FT might eventually prove to be a ‘middle ground’ between active surveillance and radical treatment, combining minimal morbidity with cancer control and the potential for retreatment.
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Affiliation(s)
- Uri Lindner
- Department of Urology, Tel Hashomer Hospital (affiliated with Tel Aviv University), 52621, Israel
| | - Nathan Lawrentschuk
- University of Melbourne, Department of Surgery, Urology Unit & Ludwig Institute for Cancer Research, Austin Hospital, Heidelberg, VIC 3084, Australia
| | - Oscar Schatloff
- Department of Urology, Assaf Harofe Medical Center (affiliated with Tel Aviv University), Zerifin 70300, Israel
| | - John Trachtenberg
- Department of Urology & Surgical Oncology, Princess Margaret Hospital, 610 University Ave., Toronto, ON M5G 2M9, Canada
| | - Arie Lindner
- Department of Urology, Assaf Harofe Medical Center (affiliated with Tel Aviv University), Zerifin 70300, Israel
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Chopra R, Burtnyk M, N’djin WA, Bronskill M. MRI-controlled transurethral ultrasound therapy for localised prostate cancer. Int J Hyperthermia 2010; 26:804-21. [DOI: 10.3109/02656736.2010.503670] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Burtnyk M, N’Djin WA, Kobelevskiy I, Bronskill M, Chopra R. 3D conformal MRI-controlled transurethral ultrasound prostate therapy: validation of numerical simulations and demonstration in tissue-mimicking gel phantoms. Phys Med Biol 2010; 55:6817-39. [DOI: 10.1088/0031-9155/55/22/014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Lindner U, Lawrentschuk N, Trachtenberg J. Image guidance for focal therapy of prostate cancer. World J Urol 2010; 28:727-34. [DOI: 10.1007/s00345-010-0604-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 09/29/2010] [Indexed: 10/18/2022] Open
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Abstract
Focal therapy is emerging as an alternative to active surveillance for the management of low-risk prostate cancer in carefully selected patients. The aim of focal therapy is long-term cancer control without the associated morbidity that plagues all radical therapies. Different energy modalities have been used to focally ablate cancer tissue, and available techniques include cryotherapy, laser ablation, high-intensity focused ultrasound and photodynamic therapy. The majority of evidence for focal therapy has come from case series and small phase I trials, and larger cohort studies with longer follow-up are only now being commenced. More data from large trials on the safety and efficacy of focal therapy are therefore required before this approach can be recommended in men with prostate cancer; in particular, studies must confirm that no viable cells remain in the region of ablation. Focal therapy might eventually prove to be a 'middle ground' between active surveillance and radical treatment, combining minimal morbidity with cancer control and the potential for re-treatment.
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MRI-guided transurethral ultrasound therapy of the prostate gland using real-time thermal mapping: initial studies. Urology 2010; 76:1506-11. [PMID: 20709381 DOI: 10.1016/j.urology.2010.04.046] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 03/31/2010] [Accepted: 04/24/2010] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To confirm the correlation between planning and thermal injury of the prostate as determined by magnetic resonance imaging (MRI) and histology in canine and humans treated with transurethral ultrasound. MATERIAL AND METHODS Canine studies: 2 sets of in vivo studies were performed under general anesthesia in 1.5 T clinical MRI. Nine dogs were treated using single transducer; 8 dogs were treated using urethral applicator with multiple transducers. Rectal cooling was maintained. After initial imaging, a target boundary was selected and high-intensity ultrasound energy delivered. The spatial temperature distribution was measured continuously every 5 seconds with MR thermometry using the proton-resonant frequency shift method. The goal was to achieve 55 °C at the target boundary. After treatment, the prostate was harvested and fixed with adjoining tissue, including rectum. Temperature maps, anatomical images, and histologic sections were registered to each other and compared. Human studies: To date, 5 patients with localized prostate cancer have been treated immediately before radical prostatectomy. Approximately 30% of the gland volume was targeted. RESULTS A continuous pattern of thermal coagulation was successfully achieved within the target region, with an average spatial precision of 1-2 mm. Radical prostatectomy was routine, with an uncomplicated postoperative course in all patients. The correlation between anatomical, thermal, and histologic images was ≤3 mm. Treatment time was <30 minutes. No thermal damage to rectal tissue was observed. CONCLUSIONS Thermal ablation within the prescribed target of the prostate has been successfully demonstrated in canine studies. The treatment is also feasible in humans.
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Burtnyk M, Chopra R, Bronskill M. Simulation study on the heating of the surrounding anatomy during transurethral ultrasound prostate therapy: A 3D theoretical analysis of patient safety. Med Phys 2010; 37:2862-75. [DOI: 10.1118/1.3426313] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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