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Onofrey JA, Staib LH, Sarkar S, Venkataraman R, Nawaf CB, Sprenkle PC, Papademetris X. Learning Non-rigid Deformations for Robust, Constrained Point-based Registration in Image-Guided MR-TRUS Prostate Intervention. Med Image Anal 2017; 39:29-43. [PMID: 28431275 DOI: 10.1016/j.media.2017.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/28/2017] [Accepted: 04/03/2017] [Indexed: 01/13/2023]
Abstract
Accurate and robust non-rigid registration of pre-procedure magnetic resonance (MR) imaging to intra-procedure trans-rectal ultrasound (TRUS) is critical for image-guided biopsies of prostate cancer. Prostate cancer is one of the most prevalent forms of cancer and the second leading cause of cancer-related death in men in the United States. TRUS-guided biopsy is the current clinical standard for prostate cancer diagnosis and assessment. State-of-the-art, clinical MR-TRUS image fusion relies upon semi-automated segmentations of the prostate in both the MR and the TRUS images to perform non-rigid surface-based registration of the gland. Segmentation of the prostate in TRUS imaging is itself a challenging task and prone to high variability. These segmentation errors can lead to poor registration and subsequently poor localization of biopsy targets, which may result in false-negative cancer detection. In this paper, we present a non-rigid surface registration approach to MR-TRUS fusion based on a statistical deformation model (SDM) of intra-procedural deformations derived from clinical training data. Synthetic validation experiments quantifying registration volume of interest overlaps of the PI-RADS parcellation standard and tests using clinical landmark data demonstrate that our use of an SDM for registration, with median target registration error of 2.98 mm, is significantly more accurate than the current clinical method. Furthermore, we show that the low-dimensional SDM registration results are robust to segmentation errors that are not uncommon in clinical TRUS data.
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Affiliation(s)
| | - Lawrence H Staib
- Department of Radiology & Biomedical Imaging, USA; Department of Electrical Engineering, USA; Department of Biomedical Engineering, USA.
| | | | | | - Cayce B Nawaf
- Department of Urology, Yale University, New Haven, Connecticut, USA.
| | | | - Xenophon Papademetris
- Department of Radiology & Biomedical Imaging, USA; Department of Biomedical Engineering, USA.
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52
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Wang J, Tanderup K, Cunha A, Damato AL, Cohen GN, Kudchadker RJ, Mourtada F. Magnetic resonance imaging basics for the prostate brachytherapist. Brachytherapy 2017; 16:715-727. [PMID: 28396178 DOI: 10.1016/j.brachy.2017.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 02/23/2017] [Accepted: 03/04/2017] [Indexed: 11/27/2022]
Abstract
Magnetic resonance imaging (MRI) is increasingly being used in radiation therapy, and integration of MRI into brachytherapy in particular is becoming more common. We present here a systematic review of the basic physics and technical aspects of incorporating MRI into prostate brachytherapy. Terminology and MRI system components are reviewed along with typical work flows in prostate high-dose-rate and low-dose-rate brachytherapy. In general, the brachytherapy workflow consists of five key components: diagnosis, implantation, treatment planning (scan + plan), implant verification, and delivery. MRI integration is discussed for diagnosis; treatment planning; and MRI-guided brachytherapy implants, in which MRI is used to guide the physical insertion of the brachytherapy applicator or needles. Considerations and challenges for establishing an MRI brachytherapy program are also discussed.
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Affiliation(s)
- Jihong Wang
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX.
| | - Kari Tanderup
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Adam Cunha
- Department of Radiation Oncology, University of California-San Francisco, CA
| | - Antonio L Damato
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Gil'ad N Cohen
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Rajat J Kudchadker
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX
| | - Firas Mourtada
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX; Department of Radiation Oncology, Helen F. Graham Cancer Center, Newark, DE; Department of Radiation Oncology, Bodine Cancer Center, Thomas Jefferson University, Philadelphia, PA.
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Rylander S, Buus S, Pedersen EM, Bentzen L, Tanderup K. Dosimetric impact of contouring and needle reconstruction uncertainties in US-, CT- and MRI-based high-dose-rate prostate brachytherapy treatment planning. Radiother Oncol 2017; 123:125-132. [PMID: 28284493 DOI: 10.1016/j.radonc.2017.01.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE The purpose was to evaluate the dosimetric impact of target contouring and needle reconstruction uncertainties in an US-, CT- and MRI-based HDR prostate BT treatment planning. MATERIAL AND METHODS US, CT, and MR images were acquired post-needle insertion in 22 HDR-BT procedures for 11 consecutive patients. Dose plans were simulated for an US-, CT- and MRI-based HDR-BT treatment planning procedure. Planning uncertainties in US- and CT-based plans were evaluated using MRI-based planning as reference. Target (CTVProstate) was re-contoured on MRI. Dose results were expressed in total equivalent dose given in 2Gy fractionation dose for EBRT (46Gy) plus 2 HDR-BT fractions. RESULTS Uncertainties in US- and CT-based planning caused the planned CTVProstate-D90% to decrease with a mean of 2.9±5.0Gy (p=0.03) and 2.9±2.9Gy (p=0.001), respectively. The intra-observer contouring variation on MRI resulted in a mean variation of 1.6±1.5Gy in CTVProstate-D90%. Reconstruction uncertainties on US resulted in a dose variation of±3Gy to the urethra, whereas data for CT were not available for this. CONCLUSIONS Uncertainties related to contouring and reconstruction in US- and CT-based HDR-BT treatment plans resulted in a systematic overestimation of the prescribed target dose. Inter-modality uncertainties (US and CT versus MR) were larger than MR intra-observer uncertainties.
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Affiliation(s)
- Susanne Rylander
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.
| | - Simon Buus
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Erik M Pedersen
- Department of Radiology, Aarhus University Hospital, Aarhus, Denmark
| | - Lise Bentzen
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Kari Tanderup
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
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Lim TY, Kudchadker RJ, Wang J, Stafford RJ, MacLellan C, Rao A, Ibbott GS, Frank SJ. Effect of pulse sequence parameter selection on signal strength in positive-contrast MRI markers for MRI-based prostate postimplant assessment. Med Phys 2017; 43:4312. [PMID: 27370146 DOI: 10.1118/1.4953635] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE For postimplant dosimetric assessment, computed tomography (CT) is commonly used to identify prostate brachytherapy seeds, at the expense of accurate anatomical contouring. Magnetic resonance imaging (MRI) is superior to CT for anatomical delineation, but identification of the negative-contrast seeds is challenging. Positive-contrast MRI markers were proposed to replace spacers to assist seed localization on MRI images. Visualization of these markers under varying scan parameters was investigated. METHODS To simulate a clinical scenario, a prostate phantom was implanted with 66 markers and 86 seeds, and imaged on a 3.0T MRI scanner using a 3D fast radiofrequency-spoiled gradient recalled echo acquisition with various combinations of scan parameters. Scan parameters, including flip angle, number of excitations, bandwidth, field-of-view, slice thickness, and encoding steps were systematically varied to study their effects on signal, noise, scan time, image resolution, and artifacts. RESULTS The effects of pulse sequence parameter selection on the marker signal strength and image noise were characterized. The authors also examined the tradeoff between signal-to-noise ratio, scan time, and image artifacts, such as the wraparound artifact, susceptibility artifact, chemical shift artifact, and partial volume averaging artifact. Given reasonable scan time and managable artifacts, the authors recommended scan parameter combinations that can provide robust visualization of the MRI markers. CONCLUSIONS The recommended MRI pulse sequence protocol allows for consistent visualization of the markers to assist seed localization, potentially enabling MRI-only prostate postimplant dosimetry.
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Affiliation(s)
- Tze Yee Lim
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and The University of Texas at Houston Graduate School of Biomedical Sciences, 6767 Bertner Avenue, Houston, Texas 77030
| | - Rajat J Kudchadker
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
| | - Jihong Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
| | - R Jason Stafford
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
| | - Christopher MacLellan
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 and The University of Texas at Houston Graduate School of Biomedical Sciences, 6767 Bertner Avenue, Houston, Texas 77030
| | - Arvind Rao
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
| | - Geoffrey S Ibbott
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
| | - Steven J Frank
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
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Khalvati F, Salmanpour A, Rahnamayan S, Haider MA, Tizhoosh HR. Sequential Registration-Based Segmentation of the Prostate Gland in MR Image Volumes. J Digit Imaging 2017; 29:254-63. [PMID: 26546179 DOI: 10.1007/s10278-015-9844-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Accurate and fast segmentation and volume estimation of the prostate gland in magnetic resonance (MR) images are necessary steps in the diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semi-automated segmentation of individual slices in T2-weighted MR image sequences. The proposed sequential registration-based segmentation (SRS) algorithm, which was inspired by the clinical workflow during medical image contouring, relies on inter-slice image registration and user interaction/correction to segment the prostate gland without the use of an anatomical atlas. It automatically generates contours for each slice using a registration algorithm, provided that the user edits and approves the marking in some previous slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid). Five radiation oncologists participated in the study where they contoured the prostate MR (T2-weighted) images of 15 patients both manually and using the SRS algorithm. Compared to the manual segmentation, on average, the SRS algorithm reduced the contouring time by 62% (a speedup factor of 2.64×) while maintaining the segmentation accuracy at the same level as the intra-user agreement level (i.e., Dice similarity coefficient of 91 versus 90%). The proposed algorithm exploits the inter-slice similarity of volumetric MR image series to achieve highly accurate results while significantly reducing the contouring time.
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Affiliation(s)
- Farzad Khalvati
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada.
| | - Aryan Salmanpour
- Department of Electrical, Computer and Software Engineering, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Shahryar Rahnamayan
- Department of Electrical, Computer and Software Engineering, University of Ontario Institute of Technology, Oshawa, ON, Canada
| | - Masoom A Haider
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada
| | - H R Tizhoosh
- Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
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Westendorp H, Hoekstra CJ, Immerzeel JJ, van de Pol SMG, Niël CGHJ, Kattevilder RAJ, Nuver TT, Minken AW, Moerland MA. Cone-beam CT-based adaptive planning improves permanent prostate brachytherapy dosimetry: An analysis of 1266 patients. Med Phys 2017; 44:1257-1267. [PMID: 28192614 DOI: 10.1002/mp.12156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 01/12/2017] [Accepted: 02/08/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate adaptive planning for permanent prostate brachytherapy and to identify the prostate regions that needed adaptation. METHODS AND MATERIALS After the implantation of stranded seeds, using real-time intraoperative planning, a transrectal ultrasound (TRUS)-scan was obtained and contoured. The positions of seeds were determined on a C-arm cone-beam computed tomography (CBCT)-scan. The CBCT-scan was registered to the TRUS-scan using fiducial gold markers. If dose coverage on the combined image-dataset was inadequate, an intraoperative adaptation was performed by placing remedial seeds. CBCT-based intraoperative dosimetry was analyzed for the prostate (D90, V100, and V150) and the urethra (D30). The effects of the adaptive dosimetry procedure for Day 30 were separately assessed. RESULTS We analyzed 1266 patients. In 17.4% of the procedures, an adaptation was performed. Without the dose contribution of the adaptation Day 30 V100 would be < 95% for half of this group. On Day 0, the increase due to the adaptation was 11.8 ± 7.2% (1SD) for D90 and 9.0 ± 6.4% for V100. On Day 30, we observed an increase in D90 of 12.3 ± 6.0% and in V100 of 4.2 ± 4.3%. For the total group, a D90 of 119.6 ± 9.1% and V100 of 97.7 ± 2.5% was achieved. Most remedial seeds were placed anteriorly near the base of the prostate. CONCLUSION CBCT-based adaptive planning enables identification of implants needing adaptation and improves prostate dose coverage. Adaptations were predominantly performed near the anterior base of the prostate.
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Affiliation(s)
- Hendrik Westendorp
- Department of Medical Physics, Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Carel J Hoekstra
- Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Jos J Immerzeel
- Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Sandrine M G van de Pol
- Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Charles G H J Niël
- Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Robert A J Kattevilder
- Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Tonnis T Nuver
- Department of Medical Physics, Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - André W Minken
- Department of Medical Physics, Department of Radiation Oncology, Radiotherapiegroep behandellocatie Deventer, Nico Bolkesteinlaan 85, 7416 SE, Deventer, The Netherlands
| | - Marinus A Moerland
- Department of Medical Physics, Department of Radiation Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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Magnetic resonance imaging in prostate brachytherapy: Evidence, clinical end points to data, and direction forward. Brachytherapy 2017; 16:659-664. [PMID: 28161432 DOI: 10.1016/j.brachy.2016.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 12/01/2016] [Accepted: 12/02/2016] [Indexed: 11/21/2022]
Abstract
The integration of multiparametric MRI into prostate brachytherapy has become a subject of interest over the past 2 decades. MRI directed high-dose-rate and low-dose-rate prostate brachytherapy offers the potential to improve treatment accuracy and standardize postprocedure quality. This article reviews the evidence to date on MRI utilization in prostate brachytherapy and postulates future pathways for MRI integration.
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Ménard C, Pambrun JF, Kadoury S. The utilization of magnetic resonance imaging in the operating room. Brachytherapy 2017; 16:754-760. [PMID: 28139421 DOI: 10.1016/j.brachy.2016.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/12/2016] [Accepted: 12/12/2016] [Indexed: 11/26/2022]
Abstract
Online image guidance in the operating room using ultrasound imaging led to the resurgence of prostate brachytherapy in the 1980s. Here we describe the evolution of integrating MRI technology in the brachytherapy suite or operating room. Given the complexity, cost, and inherent safety issues associated with MRI system integration, first steps focused on the computational integration of images rather than systems. This approach has broad appeal given minimal infrastructure costs and efficiencies comparable with standard care workflows. However, many concerns remain regarding accuracy of registration through the course of a brachytherapy procedure. In selected academic institutions, MRI systems have been integrated in or near the brachytherapy suite in varied configurations to improve the precision and quality of treatments. Navigation toolsets specifically adapted to prostate brachytherapy are in development and are reviewed.
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Affiliation(s)
- C Ménard
- University of Montréal Hospital Research Centre (CRCHUM), Montréal, QC, Canada; TECHNA Institute, University of Toronto, Toronto, ON, Canada; Princess Margaret Cancer Center, Toronto, ON, Canada.
| | - J-F Pambrun
- University of Montréal Hospital Research Centre (CRCHUM), Montréal, QC, Canada; École polytechnique de Montréal, Montréal, QC, Canada
| | - S Kadoury
- University of Montréal Hospital Research Centre (CRCHUM), Montréal, QC, Canada; École polytechnique de Montréal, Montréal, QC, Canada
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Clinical use of magnetic resonance imaging across the prostate brachytherapy workflow. Brachytherapy 2017; 16:734-742. [PMID: 28153700 DOI: 10.1016/j.brachy.2016.11.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/08/2016] [Accepted: 11/29/2016] [Indexed: 11/21/2022]
Abstract
MRI produces better soft tissue contrast than does ultrasonography or computed tomography for visualizing male pelvic anatomy and prostate cancer. Better visualization of the tumor and organs at risk could allow better conformation of the dose to the target volumes while at the same time minimizing the dose to critical structures and the associated toxicity. Although the use of MRI for prostate brachytherapy would theoretically result in an improved therapeutic ratio, its implementation been slow, mostly because of technical challenges. In this review, we describe the potential role of MRI at different steps in the treatment workflow for prostate brachytherapy: for patient selection, treatment planning, in the operating room, or for postimplant assessment. We further present the current clinical experience with MRI-guided prostate brachytherapy, both for permanent seed implantation and high-dose-rate brachytherapy.
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Yang X, Rossi PJ, Jani AB, Mao H, Zhou Z, Curran WJ, Liu T. Improved prostate delineation in prostate HDR brachytherapy with TRUS-CT deformable registration technology: A pilot study with MRI validation. J Appl Clin Med Phys 2017; 18:202-210. [PMID: 28291925 PMCID: PMC5689894 DOI: 10.1002/acm2.12040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 11/01/2016] [Accepted: 11/28/2016] [Indexed: 11/30/2022] Open
Abstract
Accurate prostate delineation is essential to ensure proper target coverage and normal-tissue sparing in prostate HDR brachytherapy. We have developed a prostate HDR brachytherapy technology that integrates intraoperative TRUS-based prostate contour into HDR treatment planning through TRUS-CT deformable registration (TCDR) to improve prostate contour accuracy. In a perspective study of 16 patients, we investigated the clinical feasibility as well as the performance of this TCDR-based HDR approach. We compared the performance of the TCDR-based approach with the conventional CT-based HDR in terms of prostate contour accuracy using MRI as the gold standard. For all patients, the average Dice prostate volume overlap was 91.1 ± 2.3% between the TCDR-based and the MRI-defined prostate volumes. In a subset of eight patients, inter and intro-observer reliability study was conducted among three experienced physicians (two radiation oncologists and one radiologist) for the TCDR-based HDR approach. Overall, a 10 to 40% improvement in prostate volume accuracy can be achieved with the TCDR-based approach as compared with the conventional CT-based prostate volumes. The TCDR-based prostate volumes match closely to the MRI-defined prostate volumes for all 3 observers (mean volume difference: 0.5 ± 7.2%, 1.8 ± 7.2%, and 3.5 ± 5.1%); while CT-based contours overestimated prostate volumes by 10.9 ± 28.7%, 13.7 ± 20.1%, and 44.7 ± 32.1%. This study has shown that the TCDR-based HDR brachytherapy is clinically feasible and can significantly improve prostate contour accuracy over the conventional CT-based prostate contour. We also demonstrated the reliability of the TCDR-based prostate delineation. This TCDR-based HDR approach has the potential to enable accurate dose planning and delivery, and potentially enhance prostate HDR treatment outcome.
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Affiliation(s)
- Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Peter J. Rossi
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Ashesh B. Jani
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Hui Mao
- Department of Radiology and Imaging Sciences and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Zhengyang Zhou
- Department of RadiologyNanjing Drum Tower HospitalNanjingChina
| | - Walter J. Curran
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
| | - Tian Liu
- Department of Radiation Oncology and Winship Cancer InstituteEmory UniversityAtlantaGAUSA
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Prostate Cancer Radiation Therapy: What Do Clinicians Have to Know? BIOMED RESEARCH INTERNATIONAL 2016; 2016:6829875. [PMID: 28116302 PMCID: PMC5225325 DOI: 10.1155/2016/6829875] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/18/2016] [Accepted: 10/31/2016] [Indexed: 12/11/2022]
Abstract
Radiotherapy (RT) for prostate cancer (PC) has steadily evolved over the last decades, with improving biochemical disease-free survival. Recently population based research also revealed an association between overall survival and doses ≥ 75.6 Gray (Gy) in men with intermediate- and high-risk PC. Examples of improved RT techniques are image-guided RT, intensity-modulated RT, volumetric modulated arc therapy, and stereotactic ablative body RT, which could facilitate further dose escalation. Brachytherapy is an internal form of RT that also developed substantially. New devices such as rectum spacers and balloons have been developed to spare rectal structures. Newer techniques like protons and carbon ions have the intrinsic characteristics maximising the dose on the tumour while minimising the effect on the surrounding healthy tissue, but clinical data are needed for confirmation in randomised phase III trials. Furthermore, it provides an overview of an important discussion issue in PC treatment between urologists and radiation oncologists: the comparison between radical prostatectomy and RT. Current literature reveals that all possible treatment modalities have the same cure rate, but a different toxicity pattern. We recommend proposing the possible different treatment modalities with their own advantages and side-effects to the individual patient. Clinicians and patients should make treatment decisions together (shared decision-making) while using patient decision aids.
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Shahedi M, Cool DW, Romagnoli C, Bauman GS, Bastian-Jordan M, Rodrigues G, Ahmad B, Lock M, Fenster A, Ward AD. Postediting prostate magnetic resonance imaging segmentation consistency and operator time using manual and computer-assisted segmentation: multiobserver study. J Med Imaging (Bellingham) 2016; 3:046002. [PMID: 27872873 DOI: 10.1117/1.jmi.3.4.046002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/19/2016] [Indexed: 11/14/2022] Open
Abstract
Prostate segmentation on T2w MRI is important for several diagnostic and therapeutic procedures for prostate cancer. Manual segmentation is time-consuming, labor-intensive, and subject to high interobserver variability. This study investigated the suitability of computer-assisted segmentation algorithms for clinical translation, based on measurements of interoperator variability and measurements of the editing time required to yield clinically acceptable segmentations. A multioperator pilot study was performed under three pre- and postediting conditions: manual, semiautomatic, and automatic segmentation. We recorded the required editing time for each segmentation and measured the editing magnitude based on five different spatial metrics. We recorded average editing times of 213, 328, and 393 s for manual, semiautomatic, and automatic segmentation respectively, while an average fully manual segmentation time of 564 s was recorded. The reduced measured postediting interoperator variability of semiautomatic and automatic segmentations compared to the manual approach indicates the potential of computer-assisted segmentation for generating a clinically acceptable segmentation faster with higher consistency. The lack of strong correlation between editing time and the values of typically used error metrics ([Formula: see text]) implies that the necessary postsegmentation editing time needs to be measured directly in order to evaluate an algorithm's suitability for clinical translation.
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Affiliation(s)
- Maysam Shahedi
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Robarts Research Institute, 1151 Richmond Street, London, Ontario N6A 5B7, Canada; University of Western Ontario, Graduate Program in Biomedical Engineering, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Derek W Cool
- University of Western Ontario, Robarts Research Institute, 1151 Richmond Street, London, Ontario N6A 5B7, Canada; University of Western Ontario, Department of Medical Imaging, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Cesare Romagnoli
- University of Western Ontario , Department of Medical Imaging, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Glenn S Bauman
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Department of Medical Biophysics, 1151 Richmond Street, London, Ontario N6A 3K7, Canada; University of Western Ontario, Department of Oncology, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Matthew Bastian-Jordan
- University of Western Ontario , Department of Medical Imaging, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - George Rodrigues
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Department of Oncology, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Belal Ahmad
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Department of Oncology, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Michael Lock
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Department of Oncology, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Aaron Fenster
- University of Western Ontario, Robarts Research Institute, 1151 Richmond Street, London, Ontario N6A 5B7, Canada; University of Western Ontario, Graduate Program in Biomedical Engineering, 1151 Richmond Street, London, Ontario N6A 3K7, Canada; University of Western Ontario, Department of Medical Imaging, 1151 Richmond Street, London, Ontario N6A 3K7, Canada; University of Western Ontario, Department of Medical Biophysics, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
| | - Aaron D Ward
- London Regional Cancer Program, 790 Commissioners Road, London, Ontario N6A 4L6, Canada; University of Western Ontario, Graduate Program in Biomedical Engineering, 1151 Richmond Street, London, Ontario N6A 3K7, Canada; University of Western Ontario, Department of Medical Biophysics, 1151 Richmond Street, London, Ontario N6A 3K7, Canada; University of Western Ontario, Department of Oncology, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
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Mashouf S, Safigholi H, Merino T, Soliman A, Ravi A, Morton G, Song WY. Sensitivity of clinically relevant dosimetric parameters to contouring uncertainty in postimplant dosimetry of low-dose-rate prostate permanent seed brachytherapy. Brachytherapy 2016; 15:774-779. [DOI: 10.1016/j.brachy.2016.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 08/12/2016] [Accepted: 08/31/2016] [Indexed: 11/26/2022]
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Zaorsky NG, Showalter TN, Ezzell GA, Nguyen PL, Assimos DG, D'Amico AV, Gottschalk AR, Gustafson GS, Keole SR, Liauw SL, Lloyd S, McLaughlin PW, Movsas B, Prestidge BR, Taira AV, Vapiwala N, Davis BJ. ACR Appropriateness Criteria ® external beam radiation therapy treatment planning for clinically localized prostate cancer, part I of II. Adv Radiat Oncol 2016; 2:62-84. [PMID: 28740916 PMCID: PMC5514238 DOI: 10.1016/j.adro.2016.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/12/2016] [Indexed: 12/24/2022] Open
Affiliation(s)
| | | | | | - Gary A Ezzell
- Mayo Clinic, Phoenix, Arizona (research author, contributing)
| | - Paul L Nguyen
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (panel vice-chair)
| | - Dean G Assimos
- University of Alabama School of Medicine, Birmingham, Alabama (American Urological Association)
| | - Anthony V D'Amico
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (American Society of Clinical Oncology)
| | | | | | | | | | - Shane Lloyd
- Huntsman Cancer Hospital, Salt Lake City, Utah
| | | | | | | | - Al V Taira
- Mills Peninsula Hospital, San Mateo, California
| | - Neha Vapiwala
- University of Pennsylvania, Philadelphia, Pennsylvania
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Intraoperative ultrasound-based planning can effectively replace postoperative CT-based planning for high-dose-rate brachytherapy for prostate cancer. Brachytherapy 2016; 15:399-405. [DOI: 10.1016/j.brachy.2016.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/06/2016] [Accepted: 04/06/2016] [Indexed: 11/17/2022]
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66
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Single fraction multimodal image guided focal salvage high-dose-rate brachytherapy for recurrent prostate cancer. J Contemp Brachytherapy 2016; 8:241-8. [PMID: 27504134 PMCID: PMC4965505 DOI: 10.5114/jcb.2016.61067] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/11/2016] [Indexed: 02/08/2023] Open
Abstract
PURPOSE We present a novel method for treatment of locally recurrent prostate cancer (PCa) following radiation therapy: focal, multimodal image guided high-dose-rate (HDR) brachytherapy. MATERIAL AND METHODS We treated two patients with recurrent PCa after primary (#1) or adjuvant (#2) external beam radiation therapy. Multiparametric magnetic resonance imaging (mpMRI), choline, positron emission tomography combined with computed tomography (PET/CT), or prostate-specific membrane antigen (PSMA)-PET combined with CT identified a single intraprostatic lesion. Positron emission tomography or magnetic resonance imaging - transrectal ultrasound (MRI-TRUS) fusion guided transperineal biopsy confirmed PCa within each target lesion. We defined a PET and mpMRI based gross tumor volume (GTV). A 5 mm isotropic margin was applied additionally to each lesion to generate a planning target volume (PTV), which accounts for technical fusion inaccuracies. A D90 of 18 Gy was intended in one fraction to each PTV using ultrasound guided HDR brachytherapy. RESULTS Six month follow-up showed adequate prostate specific antygen (PSA) decline in both patients (ΔPSA 83% in patient 1 and ΔPSA 59.3% in patient 2). Follow-up 3-tesla MRI revealed regressive disease in both patients and PSMA-PET/CT showed no evidence of active disease in patient #1. No acute or late toxicities occurred. CONCLUSIONS Single fraction, focal, multimodal image guided salvage HDR brachytherapy for recurrent prostate cancer is a feasible therapy for selected patients with single lesions. This approach has to be evaluated in larger clinical trials.
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67
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Development of a magnetic resonance imaging protocol to visualize encapsulated contrast agent markers in prostate brachytherapy recipients: initial patient experience. J Contemp Brachytherapy 2016; 8:235-42. [PMID: 27504133 PMCID: PMC4965498 DOI: 10.5114/jcb.2016.60506] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 05/29/2016] [Indexed: 11/30/2022] Open
Abstract
Purpose Computed tomography (CT)-based prostate post-implant dosimetry allows for definitive seed localization but is associated with high interobserver variation in prostate contouring. Currently, magnetic resonance imaging (MRI)-based post-implant dosimetry allows for accurate anatomical delineation but is limited due to inconsistent seed localization. Encapsulated contrast agent markers were previously proposed to overcome the seed localization limitation on MRI images by placing hyperintense markers adjacent to hypointense seeds. The aim of this study was to assess the appearance of these markers in prostatic tissue, and develop an MRI protocol to enable marker visualization. Material and methods We acquired MRI scans in prostate implant patients (n = 10) on day 0 (day of implant) and day 30 (month after implant). Before implantation of the markers, the routine post-implant MRI protocol included a 3D T2-weighted fast-spin-echo (FSE) sequence with which markers and seeds could not be clearly visualized. To visualize the MRI markers, a 3D fast radiofrequency-spoiled gradient-recalled echo (FSPGR) sequence was evaluated for marker and seed visibility, as well as prostate boundary definitions. Results The 3D FSPGR sequence allowed for the visualization of markers in the prostate, enabling the distinction of signal voids as seeds versus needle tracks. The updated post-implant MRI protocol consists of this 3D FSPGR scan and an optional 3D T2-weighted FSE scan. The optional 3D T2-weighted FSE sequence may be employed to better visualize intraprostatic detail. We also described the observed image artifacts, including seed susceptibility, marker chemical shift, partial volume averaging, motion, and wraparound artifacts. Conclusions We have demonstrated an MRI protocol for use with hyperintense encapsulated contrast agent markers to assist in the identification of hypointense seeds.
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68
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Kardell M, Magnusson M, Sandborg M, Alm Carlsson G, Jeuthe J, Malusek A. AUTOMATIC SEGMENTATION OF PELVIS FOR BRACHYTHERAPY OF PROSTATE. RADIATION PROTECTION DOSIMETRY 2016; 169:398-404. [PMID: 26567322 DOI: 10.1093/rpd/ncv461] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Advanced model-based iterative reconstruction algorithms in quantitative computed tomography (CT) perform automatic segmentation of tissues to estimate material properties of the imaged object. Compared with conventional methods, these algorithms may improve quality of reconstructed images and accuracy of radiation treatment planning. Automatic segmentation of tissues is, however, a difficult task. The aim of this work was to develop and evaluate an algorithm that automatically segments tissues in CT images of the male pelvis. The newly developed algorithm (MK2014) combines histogram matching, thresholding, region growing, deformable model and atlas-based registration techniques for the segmentation of bones, adipose tissue, prostate and muscles in CT images. Visual inspection of segmented images showed that the algorithm performed well for the five analysed images. The tissues were identified and outlined with accuracy sufficient for the dual-energy iterative reconstruction algorithm whose aim is to improve the accuracy of radiation treatment planning in brachytherapy of the prostate.
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Affiliation(s)
- M Kardell
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden
| | - M Magnusson
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden Computer Vision Laboratory, Department of Electrical Engineering, Linköping University, SE-58183 Linköping, Sweden
| | - M Sandborg
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden
| | - G Alm Carlsson
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden
| | - J Jeuthe
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden
| | - A Malusek
- Medical Radiation Physics, Department of Medical and Health Sciences and Center for Medical Image Science and Visualisation, Linköping University, SE-58185 Linköping, Sweden
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69
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Evaluation of a new transperineal ultrasound probe for inter-fraction image-guidance for definitive and post-operative prostate cancer radiotherapy. Phys Med 2016; 32:499-505. [PMID: 26851164 DOI: 10.1016/j.ejmp.2016.01.481] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/14/2016] [Accepted: 01/21/2016] [Indexed: 11/21/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate a new system based on transperineal ultrasound (TP-US) acquisitions for prostate and post-prostatectomy pre-treatment positioning by comparing this device to cone-beam computed tomography (CBCT). METHODS The differences between CBCT/CT and TP-US/TP-US registrations were analyzed on 427 and 453 sessions for 13 prostate and 14 post-prostatectomy patients, respectively. The inter-operator variability (IOV) of the registration process, and the impact and variability of the probe pressure were also evaluated. RESULTS CBCT and TP-US shift agreements at ± 5 mm were 76.6%, 95.1%, 96.3% and 90.3%, 85.0%, 97.6% in anterior-posterior, superior-inferior and left-right directions, for prostate and post-prostatectomy patients, respectively. IOV values were similar between the 2 modalities. Displacements above 5 mm due to strong pressures were observed on both localizations, but such pressures were rarely reproduced during treatment courses. CONCLUSIONS High concordance between CBCT/CT and TP-US/TP-US localization of prostates or prostatic beds was found in this study. TP-US based prepositioning is a feasible method to ensure accurate treatment delivery, and represents an attractive alternative to invasive and/or irradiating imaging modalities.
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70
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Khallaghi S, Sánchez CA, Rasoulian A, Nouranian S, Romagnoli C, Abdi H, Chang SD, Black PC, Goldenberg L, Morris WJ, Spadinger I, Fenster A, Ward A, Fels S, Abolmaesumi P. Statistical Biomechanical Surface Registration: Application to MR-TRUS Fusion for Prostate Interventions. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:2535-2549. [PMID: 26080380 DOI: 10.1109/tmi.2015.2443978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A common challenge when performing surface-based registration of images is ensuring that the surfaces accurately represent consistent anatomical boundaries. Image segmentation may be difficult in some regions due to either poor contrast, low slice resolution, or tissue ambiguities. To address this, we present a novel non-rigid surface registration method designed to register two partial surfaces, capable of ignoring regions where the anatomical boundary is unclear. Our probabilistic approach incorporates prior geometric information in the form of a statistical shape model (SSM), and physical knowledge in the form of a finite element model (FEM). We validate results in the context of prostate interventions by registering pre-operative magnetic resonance imaging (MRI) to 3D transrectal ultrasound (TRUS). We show that both the geometric and physical priors significantly decrease net target registration error (TRE), leading to TREs of 2.35 ± 0.81 mm and 2.81 ± 0.66 mm when applied to full and partial surfaces, respectively. We investigate robustness in response to errors in segmentation, varying levels of missing data, and adjusting the tunable parameters. Results demonstrate that the proposed surface registration method is an efficient, robust, and effective solution for fusing data from multiple modalities.
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71
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Barkati M, Simard D, Taussky D, Delouya G. Magnetic resonance imaging for prostate bed radiotherapy planning: An inter- and intra-observer variability study. J Med Imaging Radiat Oncol 2015; 60:255-9. [DOI: 10.1111/1754-9485.12416] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/10/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Maroie Barkati
- Department of Radiation Oncology; Centre hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame; Montreal Québec Canada
| | - Dany Simard
- Department of Radiation Oncology; Centre hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame; Montreal Québec Canada
| | - Daniel Taussky
- Department of Radiation Oncology; Centre hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame; Montreal Québec Canada
| | - Guila Delouya
- Department of Radiation Oncology; Centre hospitalier de l'Université de Montréal (CHUM), Hôpital Notre-Dame; Montreal Québec Canada
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72
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Khallaghi S, Sánchez CA, Rasoulian A, Sun Y, Imani F, Khojaste A, Goksel O, Romagnoli C, Abdi H, Chang S, Mousavi P, Fenster A, Ward A, Fels S, Abolmaesumi P. Biomechanically Constrained Surface Registration: Application to MR-TRUS Fusion for Prostate Interventions. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:2404-2414. [PMID: 26054062 DOI: 10.1109/tmi.2015.2440253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In surface-based registration for image-guided interventions, the presence of missing data can be a significant issue. This often arises with real-time imaging modalities such as ultrasound, where poor contrast can make tissue boundaries difficult to distinguish from surrounding tissue. Missing data poses two challenges: ambiguity in establishing correspondences; and extrapolation of the deformation field to those missing regions. To address these, we present a novel non-rigid registration method. For establishing correspondences, we use a probabilistic framework based on a Gaussian mixture model (GMM) that treats one surface as a potentially partial observation. To extrapolate and constrain the deformation field, we incorporate biomechanical prior knowledge in the form of a finite element model (FEM). We validate the algorithm, referred to as GMM-FEM, in the context of prostate interventions. Our method leads to a significant reduction in target registration error (TRE) compared to similar state-of-the-art registration algorithms in the case of missing data up to 30%, with a mean TRE of 2.6 mm. The method also performs well when full segmentations are available, leading to TREs that are comparable to or better than other surface-based techniques. We also analyze robustness of our approach, showing that GMM-FEM is a practical and reliable solution for surface-based registration.
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73
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Westendorp H, Nuver TT, Moerland MA, Minken AW. An automated, fast and accurate registration method to link stranded seeds in permanent prostate implants. Phys Med Biol 2015; 60:N391-403. [DOI: 10.1088/0031-9155/60/20/n391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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74
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Ultrasound versus Cone-beam CT image-guided radiotherapy for prostate and post-prostatectomy pretreatment localization. Phys Med 2015; 31:997-1004. [PMID: 26422200 DOI: 10.1016/j.ejmp.2015.07.147] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 07/15/2015] [Accepted: 07/28/2015] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To evaluate the accuracy of an intra-modality trans-abdominal ultrasound (TA-US) device against soft-tissue based Cone-Beam Computed tomography (CBCT) registration for prostate and post-prostatectomy pre-treatment positioning. METHODS The differences between CBCT and US shifts were calculated on 25 prostate cancer patients (cohort A) and 11 post-prostatectomy patients (cohort B), resulting in 284 and 106 paired shifts for cohorts A and B, respectively. As a second step, a corrective method was applied to the US registration results to decrease the systematic shifts observed between TA-US and CBCT results. This method consisted of subtracting the mean difference obtained between US and CBCT registration results during the first 3 sessions from the US registration results of the subsequent sessions. Inter-operator registration variability (IOV) was also investigated for both modalities. RESULTS After initial review, about 20% of the US images were excluded because of insufficient quality. The average differences between US and CBCT were: 2.8 ± 4.1 mm, -0.9 ± 4.2 mm, 0.4 ± 3.4 mm for cohort A and 1.3 ± 5.0 mm, -2.3 ± 4.6 mm, 0.5 ± 2.9 mm for cohort B, in the anterior-posterior (AP), superior-inferior (SI) and lateral (LR) directions, respectively. After applying the corrective method, only the differences in the AP direction remained significant (p < 0.05). The IOV values were between 0.6-2.0 mm and 2.1-3.5 mm for the CBCT and TA-US modalities, respectively. CONCLUSIONS Based on the obtained results and on the image quality, the TA-US imaging modality is not safely interchangeable with CBCT for pre-treatment repositioning. Treatment margins adaptation based on the correction of the systematic shifts should be considered.
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75
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Liu D, Meyer T, Usmani N, Kay I, Husain S, Angyalfi S, Sloboda R. Implanted brachytherapy seed movement reflecting transrectal ultrasound probe-induced prostate deformation. Brachytherapy 2015; 14:809-17. [PMID: 26392375 DOI: 10.1016/j.brachy.2015.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 08/13/2015] [Accepted: 08/17/2015] [Indexed: 12/01/2022]
Abstract
PURPOSE Compression of the prostate during transrectal ultrasound-guided permanent prostate brachytherapy is not accounted for during treatment planning. Dosimetry effects are expected to be small but have not been reported. The study aims to characterize the seed movement and prostate deformation due to probe pressure and to estimate the effects on dosimetry. METHODS AND MATERIALS C-arm fluoroscopy imaging was performed to reconstruct the implanted seed distributions (compressed and relaxed prostate) for 10 patients immediately after implantation. The compressed prostate was delineated on ultrasound and registered to the fluoroscopy-derived seed distribution via manual seed localization. Thin-plate spline mapping, generated with implanted seeds as control points, was used to characterize the deformation field and to infer the prostate contour in the absence of probe compression. Differences in TG-43 dosimetry for the compressed prostate and that on probe removal were calculated. RESULTS Systematic seed movement patterns were observed on probe removal. Elastic decompression was characterized by expansion in the anterior-posterior direction and contraction in the superior-inferior and lateral directions up to 4 mm. Bilateral shearing in the anterior direction was up to 6 mm, resulting in contraction of the 145 Gy prescription isodose line by 2 mm with potential consequences for the posterior-lateral margin. The average whole prostate D90 increased by 2% of prescription dose (6% max; p < 0.01). CONCLUSIONS The current investigation presents a novel study on ultrasound probe-induced deformation. Seed movements were characterized, and the associated dosimetry effects were nonnegligible, contrary to common expectation.
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Affiliation(s)
- Derek Liu
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
| | - Tyler Meyer
- Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta, Canada; Department of Oncology, University of Calgary, Calgary, Alberta, Canada
| | - Nawaid Usmani
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada; Department of Radiation Oncology, Cross Cancer Institute, Edmonton, Alberta, Canada
| | - Ian Kay
- Department of Medical Physics and Bioengineering, Canterbury District Health Board, Christchurch, New Zealand
| | - Siraj Husain
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada; Department of Radiation Oncology, Tom Baker Cancer Centre, Calgary, Alberta, Canada
| | - Steve Angyalfi
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada; Department of Radiation Oncology, Tom Baker Cancer Centre, Calgary, Alberta, Canada
| | - Ron Sloboda
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
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Occlusion of the Internal Iliac Artery Is Associated with Smaller Prostate and Decreased Urinary Tract Symptoms. J Vasc Interv Radiol 2015; 26:1305-10. [DOI: 10.1016/j.jvir.2015.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 03/12/2015] [Accepted: 04/22/2015] [Indexed: 11/21/2022] Open
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77
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Mousavi SR, Wang H, Hesabgar SM, Scholl TJ, Samani A. A novel shape-similarity-based elastography technique for prostate cancer assessment. Med Phys 2015; 42:5110-9. [DOI: 10.1118/1.4927572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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78
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Effect of a urinary catheter on seed position and rectal and bladder doses in CT-based post-implant dosimetry for prostate cancer brachytherapy. J Contemp Brachytherapy 2015. [PMID: 26207109 PMCID: PMC4499521 DOI: 10.5114/jcb.2015.52624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To assess the variability in rectal and bladder dosimetric parameters determined according to post-implant computed tomography (CT) images in patients with or without a urethral catheter. MATERIAL AND METHODS Patients with prostate cancer who were scheduled to undergo CT after brachytherapy between October 2012 and January 2014 were included. We obtained CT series with and without a urinary catheter in each patient. We compared the rectal and bladder doses in 18 patients on each CT series. RESULTS The shifts in the seed positions between with and without a catheter in place were 1.3 ± 0.3 mm (mean ± standard deviation). The radiation doses to the rectum, as determined on the CT series, with a urethral catheter were higher than those on CT without a catheter (p < 0.001). Radiation doses to the bladder with a catheter were significantly lower than those without a catheter (p = 0.027). CONCLUSIONS Post-implant dosimetry (PID) with no catheter showed significantly lower rectal doses and higher bladder doses than those of PID with a catheter. We recommend the PID procedure for CT images in patients without a catheter. Use of CT with a catheter is limited to identifying urethral position.
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79
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Shahedi M, Cool DW, Romagnoli C, Bauman GS, Bastian-Jordan M, Gibson E, Rodrigues G, Ahmad B, Lock M, Fenster A, Ward AD. Spatially varying accuracy and reproducibility of prostate segmentation in magnetic resonance images using manual and semiautomated methods. Med Phys 2015; 41:113503. [PMID: 25370674 DOI: 10.1118/1.4899182] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Three-dimensional (3D) prostate image segmentation is useful for cancer diagnosis and therapy guidance, but can be time-consuming to perform manually and involves varying levels of difficulty and interoperator variability within the prostatic base, midgland (MG), and apex. In this study, the authors measured accuracy and interobserver variability in the segmentation of the prostate on T2-weighted endorectal magnetic resonance (MR) imaging within the whole gland (WG), and separately within the apex, midgland, and base regions. METHODS The authors collected MR images from 42 prostate cancer patients. Prostate border delineation was performed manually by one observer on all images and by two other observers on a subset of ten images. The authors used complementary boundary-, region-, and volume-based metrics [mean absolute distance (MAD), Dice similarity coefficient (DSC), recall rate, precision rate, and volume difference (ΔV)] to elucidate the different types of segmentation errors that they observed. Evaluation for expert manual and semiautomatic segmentation approaches was carried out. Compared to manual segmentation, the authors' semiautomatic approach reduces the necessary user interaction by only requiring an indication of the anteroposterior orientation of the prostate and the selection of prostate center points on the apex, base, and midgland slices. Based on these inputs, the algorithm identifies candidate prostate boundary points using learned boundary appearance characteristics and performs regularization based on learned prostate shape information. RESULTS The semiautomated algorithm required an average of 30 s of user interaction time (measured for nine operators) for each 3D prostate segmentation. The authors compared the segmentations from this method to manual segmentations in a single-operator (mean whole gland MAD = 2.0 mm, DSC = 82%, recall = 77%, precision = 88%, and ΔV = - 4.6 cm(3)) and multioperator study (mean whole gland MAD = 2.2 mm, DSC = 77%, recall = 72%, precision = 86%, and ΔV = - 4.0 cm(3)). These results compared favorably with observed differences between manual segmentations and a simultaneous truth and performance level estimation reference for this data set (whole gland differences as high as MAD = 3.1 mm, DSC = 78%, recall = 66%, precision = 77%, and ΔV = 15.5 cm(3)). The authors found that overall, midgland segmentation was more accurate and repeatable than the segmentation of the apex and base, with the base posing the greatest challenge. CONCLUSIONS The main conclusions of this study were that (1) the semiautomated approach reduced interobserver segmentation variability; (2) the segmentation accuracy of the semiautomated approach, as well as the accuracies of recently published methods from other groups, were within the range of observed expert variability in manual prostate segmentation; and (3) further efforts in the development of computer-assisted segmentation would be most productive if focused on improvement of segmentation accuracy and reduction of variability within the prostatic apex and base.
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Affiliation(s)
- Maysam Shahedi
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada; Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7, Canada; and Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Derek W Cool
- Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7, Canadaand The Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Cesare Romagnoli
- The Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Glenn S Bauman
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada; The Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7, Canada; and The Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Matthew Bastian-Jordan
- The Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Eli Gibson
- Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7, Canada and Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - George Rodrigues
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada and The Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Belal Ahmad
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada and The Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Michael Lock
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada and The Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Aaron Fenster
- Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario N6A 3K7, Canada; The Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7, Canada; and The Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Aaron D Ward
- London Regional Cancer Program, London, Ontario N6A 5W9, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario N6A 3K7, Canada; The Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7, Canada; and The Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7, Canada
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Converting from CT- to MRI-only-based target definition in radiotherapy of localized prostate cancer. Strahlenther Onkol 2015; 191:862-8. [DOI: 10.1007/s00066-015-0868-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/12/2015] [Indexed: 11/30/2022]
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Gardner SJ, Wen N, Kim J, Liu C, Pradhan D, Aref I, Cattaneo R, Vance S, Movsas B, Chetty IJ, Elshaikh MA. Contouring variability of human- and deformable-generated contours in radiotherapy for prostate cancer. Phys Med Biol 2015; 60:4429-47. [PMID: 25988718 DOI: 10.1088/0031-9155/60/11/4429] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was designed to evaluate contouring variability of human-and deformable-generated contours on planning CT (PCT) and CBCT for ten patients with low-or intermediate-risk prostate cancer. For each patient in this study, five radiation oncologists contoured the prostate, bladder, and rectum, on one PCT dataset and five CBCT datasets. Consensus contours were generated using the STAPLE method in the CERR software package. Observer contours were compared to consensus contour, and contour metrics (Dice coefficient, Hausdorff distance, Contour Distance, Center-of-Mass [COM] Deviation) were calculated. In addition, the first day CBCT was registered to subsequent CBCT fractions (CBCTn: CBCT2-CBCT5) via B-spline Deformable Image Registration (DIR). Contours were transferred from CBCT1 to CBCTn via the deformation field, and contour metrics were calculated through comparison with consensus contours generated from human contour set. The average contour metrics for prostate contours on PCT and CBCT were as follows: Dice coefficient-0.892 (PCT), 0.872 (CBCT-Human), 0.824 (CBCT-Deformed); Hausdorff distance-4.75 mm (PCT), 5.22 mm (CBCT-Human), 5.94 mm (CBCT-Deformed); Contour Distance (overall contour)-1.41 mm (PCT), 1.66 mm (CBCT-Human), 2.30 mm (CBCT-Deformed); COM Deviation-2.01 mm (PCT), 2.78 mm (CBCT-Human), 3.45 mm (CBCT-Deformed). For human contours on PCT and CBCT, the difference in average Dice coefficient between PCT and CBCT (approx. 2%) and Hausdorff distance (approx. 0.5 mm) was small compared to the variation between observers for each patient (standard deviation in Dice coefficient of 5% and Hausdorff distance of 2.0 mm). However, additional contouring variation was found for the deformable-generated contours (approximately 5.0% decrease in Dice coefficient and 0.7 mm increase in Hausdorff distance relative to human-generated contours on CBCT). Though deformable contours provide a reasonable starting point for contouring on CBCT, we conclude that contours generated with B-Spline DIR require physician review and editing if they are to be used in the clinic.
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Affiliation(s)
- Stephen J Gardner
- Department of Radiation Oncology, Josephine Ford Cancer Institute, Henry Ford Health System, Detroit, MI 48202, USA
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A new two-step accurate CT-MRI fusion technique for post-implant prostate cancer. J Contemp Brachytherapy 2015; 7:117-21. [PMID: 26034491 PMCID: PMC4444459 DOI: 10.5114/jcb.2015.51290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 01/18/2015] [Accepted: 02/24/2015] [Indexed: 01/14/2023] Open
Abstract
Purpose To develop an accurate method of fusing computed tomography (CT) with magnetic resonance imaging (MRI) for post-implant dosimetry after prostate seed implant brachytherapy. Material and methods Prostate cancer patients were scheduled to undergo CT and MRI after brachytherapy. We obtained the three MRI sequences on fat-suppressed T1-weighted imaging (FST1-WI), T2-weighted imaging (T2-WI), and T2*-weighted imaging (T2*-WI) in each patient. We compared the lengths and widths of 450 seed source images in the 10 study patients on CT, FST1-WI, T2-WI, and T2*-WI. After CT-MRI fusion using source positions by the least-squares method, we decided the center of each seed source and measured the distance of these centers between CT and MRI to estimate the fusion accuracy. Results The measured length and width of the seeds were 6.1 ± 0.5 mm (mean ± standard deviation) and 3.2 ± 0.2 mm on CT, 5.9 ± 0.4 mm, and 2.4 ± 0.2 mm on FST1-WI, 5.5 ± 0.5 mm and 1.8 ± 0.2 mm on T2-WI, and 7.8 ± 1.0 mm and 4.1 ± 0.7 mm on T2*-WI, respectively. The measured source location shifts on CT/FST1-WI and CT/T2-WI after image fusion in the 10 study patients were 0.9 ± 0.4 mm and 1.4 ± 0.2 mm, respectively. The shift on CT/FST1-WI was less than on CT/T2-WI (p = 0.005). Conclusions For post-implant dosimetry after prostate seed implant brachytherapy, more accurate fusion of CT and T2-WI is achieved if CT and FST1-WI are fused first using the least-squares method and the center position of each source, followed by fusion of the FST1-WI and T2-WI images. This method is more accurate than direct image fusion.
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Fedorov A, Khallaghi S, Sánchez CA, Lasso A, Fels S, Tuncali K, Sugar EN, Kapur T, Zhang C, Wells W, Nguyen PL, Abolmaesumi P, Tempany C. Open-source image registration for MRI-TRUS fusion-guided prostate interventions. Int J Comput Assist Radiol Surg 2015; 10:925-34. [PMID: 25847666 DOI: 10.1007/s11548-015-1180-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/17/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE We propose two software tools for non-rigid registration of MRI and transrectal ultrasound (TRUS) images of the prostate. Our ultimate goal is to develop an open-source solution to support MRI-TRUS fusion image guidance of prostate interventions, such as targeted biopsy for prostate cancer detection and focal therapy. It is widely hypothesized that image registration is an essential component in such systems. METHODS The two non-rigid registration methods are: (1) a deformable registration of the prostate segmentation distance maps with B-spline regularization and (2) a finite element-based deformable registration of the segmentation surfaces in the presence of partial data. We evaluate the methods retrospectively using clinical patient image data collected during standard clinical procedures. Computation time and Target Registration Error (TRE) calculated at the expert-identified anatomical landmarks were used as quantitative measures for the evaluation. RESULTS The presented image registration tools were capable of completing deformable registration computation within 5 min. Average TRE was approximately 3 mm for both methods, which is comparable with the slice thickness in our MRI data. Both tools are available under nonrestrictive open-source license. CONCLUSIONS We release open-source tools that may be used for registration during MRI-TRUS-guided prostate interventions. Our tools implement novel registration approaches and produce acceptable registration results. We believe these tools will lower the barriers in development and deployment of interventional research solutions and facilitate comparison with similar tools.
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84
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Fontanarosa D, van der Meer S, Bamber J, Harris E, O'Shea T, Verhaegen F. Review of ultrasound image guidance in external beam radiotherapy: I. Treatment planning and inter-fraction motion management. Phys Med Biol 2015; 60:R77-114. [PMID: 25592664 DOI: 10.1088/0031-9155/60/3/r77] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In modern radiotherapy, verification of the treatment to ensure the target receives the prescribed dose and normal tissues are optimally spared has become essential. Several forms of image guidance are available for this purpose. The most commonly used forms of image guidance are based on kilovolt or megavolt x-ray imaging. Image guidance can also be performed with non-harmful ultrasound (US) waves. This increasingly used technique has the potential to offer both anatomical and functional information.This review presents an overview of the historical and current use of two-dimensional and three-dimensional US imaging for treatment verification in radiotherapy. The US technology and the implementation in the radiotherapy workflow are described. The use of US guidance in the treatment planning process is discussed. The role of US technology in inter-fraction motion monitoring and management is explained, and clinical studies of applications in areas such as the pelvis, abdomen and breast are reviewed. A companion review paper (O'Shea et al 2015 Phys. Med. Biol. submitted) will extensively discuss the use of US imaging for intra-fraction motion quantification and novel applications of US technology to RT.
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Affiliation(s)
- Davide Fontanarosa
- Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center (MUMC), Maastricht 6201 BN, the Netherlands. Oncology Solutions Department, Philips Research, High Tech Campus 34, Eindhoven 5656 AE, the Netherlands
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Prostate volume and implant configuration during 48 hours of temporary prostate brachytherapy: limited effect of oedema. Radiat Oncol 2014; 9:272. [PMID: 25497373 PMCID: PMC4268808 DOI: 10.1186/s13014-014-0272-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 11/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In pulsed-dose rate prostate brachytherapy the dose is delivered during 48 hours after implantation, making the treatment sensitive to oedematic effects possibly affecting dose delivery. The aim was to study changes in prostate volume during treatment by analysing catheter configurations on three subsequent scans. METHODS Prostate expansion was determined for 19 patients from the change in spatial distribution of the implanted catheters, using three CT-scans: a planning CT (CT1) and two CTs after 24 and 48 hours (CT2, CT3). An additional 4 patients only received one repeat CT (after 24 hours). The mean radial distance (MRD) of all dwell positions to the geometric centre of all dwell positions used was calculated to evaluate volume changes. From three implanted markers changes in inter-marker distances were assessed. The relative shifts of all dwell positions were determined using catheter- and marker-based registrations. Wilcoxon signed-rank tests were performed to compare the results from the different time points. RESULTS The MRDs measured on the two repeat CTs were significantly different from CT1. The mean prostate volume change derived from the difference in MRD was +4.3% (range -9.3% to +15.6%) for CT1-CT2 (p < .05) and +4.4% (range -7.5% to +16.3%) for CT1-CT3 (p < .05). These values represented a mean increase of 1.2 cm(3) in the first 24 hours and 1.5 cm(3) in the subsequent 24 hours. There was no clear sign of prostate expansion from the change in inter-marker distance (CT1-CT2: 0.2 ± 1.8 mm; CT1-CT3: 0.6 ± 2.2 mm). Catheter configuration remained stable; shifts in catheter positions were largest in the C-C direction: 0 ± 1.8 mm for CT1-CT2 and 0 ± 1.4 mm for CT2-CT3. CONCLUSIONS The volume changes derived from catheter displacements were small and therefore considered clinically insignificant. Implant configuration remains stable during 2 days of treatment, confirming the safety of this technique.
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Presles B, Fargier-Voiron M, Biston MC, Lynch R, Munoz A, Liebgott H, Pommier P, Rit S, Sarrut D. Semiautomatic registration of 3D transabdominal ultrasound images for patient repositioning during postprostatectomy radiotherapy. Med Phys 2014; 41:122903. [DOI: 10.1118/1.4901642] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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87
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Yang X, Rossi P, Ogunleye T, Marcus DM, Jani AB, Mao H, Curran WJ, Liu T. Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy. Med Phys 2014; 41:111915. [PMID: 25370648 PMCID: PMC4241831 DOI: 10.1118/1.4897615] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. METHODS The authors' approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1-3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS-CT image fusion. After TRUS-CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. RESULTS For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors' approach and the MRI-based volume was 7.28% ± 0.86%, and the prostate volume Dice overlap coefficient was 91.89% ± 1.19%. CONCLUSIONS The authors have developed a novel approach to improve prostate contour utilizing intraoperative TRUS-based prostate volume in the CT-based prostate HDR treatment planning, demonstrated its clinical feasibility, and validated its accuracy with MRIs. The proposed segmentation method would improve prostate delineations, enable accurate dose planning and treatment delivery, and potentially enhance the treatment outcome of prostate HDR brachytherapy.
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Affiliation(s)
- Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Peter Rossi
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Tomi Ogunleye
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - David M Marcus
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Ashesh B Jani
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Hui Mao
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia 30322
| | - Walter J Curran
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
| | - Tian Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322
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Sandhu GK, Angyalfi S, Dunscombe PB, Khan RF. Is tissue harmonic ultrasound imaging (THI) of the prostatic urethra and rectum superior to brightness (B) mode imaging? An observer study. Phys Med 2014; 30:662-8. [DOI: 10.1016/j.ejmp.2014.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/27/2014] [Accepted: 04/08/2014] [Indexed: 12/01/2022] Open
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Tao R, Tavakoli M, Sloboda R, Usmani N. A comparison of US- versus MR-based 3-D Prostate Shapes Using Radial Basis Function Interpolation and Statistical Shape Models. IEEE J Biomed Health Inform 2014; 19:623-34. [PMID: 24860042 DOI: 10.1109/jbhi.2014.2324975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper presents a comparison of three-dimensional (3-D) segmentations of the prostate, based on two-dimensional (2-D) manually segmented contours, obtained using ultrasound (US) and magnetic resonance (MR) imaging data collected from 40 patients diagnosed with localized prostate cancer and scheduled to receive brachytherapy treatment. The approach we propose here for 3-D prostate segmentation first uses radial basis function interpolation to construct a 3-D point distribution model for each prostate. Next, a modified principal axis transformation is utilized for rigid registration of the US and MR images of the same prostate in preparation for the following shape comparison. Then, statistical shape models are used to capture the segmented 3-D prostate geometries for the subsequent cross-modality comparison. Our study includes not only cross-modality geometric comparisons in terms of prostate volumes and dimensions, but also an investigation of interchangeability of the two imaging modalities in terms of automatic contour segmentation at the pre-implant planning stage of prostate brachytherapy treatment. By developing a new scheme to compare the two imaging modalities in terms of the segmented 3-D shapes, we have taken a first step necessary for building coupled US-MR segmentation strategies for prostate brachytherapy pre-implant planning, which at present is predominantly informed by US images only.
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Wang W, Wu L. Computed Tomography-guided Percutaneous Permanent Iodine-125 Implantation for Patients with Malignant Osseous Tumors. TUMORI JOURNAL 2014. [DOI: 10.1177/1578.17208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Weiyu Wang
- Shandong Medical Imaging Research Institute, Shandong University Medical College, Jinan
- Department of Radiology, Affiliated Anhui Provincial Hospital, Anhui Medical University, Hefei, China
| | - Lebin Wu
- Shandong Medical Imaging Research Institute, Shandong University Medical College, Jinan
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91
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Impact of probe pressure variability on prostate localization for ultrasound-based image-guided radiotherapy. Radiother Oncol 2014; 111:132-7. [DOI: 10.1016/j.radonc.2014.02.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/24/2014] [Accepted: 02/15/2014] [Indexed: 11/17/2022]
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Qiu W, Yuan J, Ukwatta E, Sun Y, Rajchl M, Fenster A. Dual optimization based prostate zonal segmentation in 3D MR images. Med Image Anal 2014; 18:660-73. [PMID: 24721776 DOI: 10.1016/j.media.2014.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 02/18/2014] [Accepted: 02/24/2014] [Indexed: 10/25/2022]
Abstract
Efficient and accurate segmentation of the prostate and two of its clinically meaningful sub-regions: the central gland (CG) and peripheral zone (PZ), from 3D MR images, is of great interest in image-guided prostate interventions and diagnosis of prostate cancer. In this work, a novel multi-region segmentation approach is proposed to simultaneously segment the prostate and its two major sub-regions from only a single 3D T2-weighted (T2w) MR image, which makes use of the prior spatial region consistency and incorporates a customized prostate appearance model into the segmentation task. The formulated challenging combinatorial optimization problem is solved by means of convex relaxation, for which a novel spatially continuous max-flow model is introduced as the dual optimization formulation to the studied convex relaxed optimization problem with region consistency constraints. The proposed continuous max-flow model derives an efficient duality-based algorithm that enjoys numerical advantages and can be easily implemented on GPUs. The proposed approach was validated using 18 3D prostate T2w MR images with a body-coil and 25 images with an endo-rectal coil. Experimental results demonstrate that the proposed method is capable of efficiently and accurately extracting both the prostate zones: CG and PZ, and the whole prostate gland from the input 3D prostate MR images, with a mean Dice similarity coefficient (DSC) of 89.3±3.2% for the whole gland (WG), 82.2±3.0% for the CG, and 69.1±6.9% for the PZ in 3D body-coil MR images; 89.2±3.3% for the WG, 83.0±2.4% for the CG, and 70.0±6.5% for the PZ in 3D endo-rectal coil MR images. In addition, the experiments of intra- and inter-observer variability introduced by user initialization indicate a good reproducibility of the proposed approach in terms of volume difference (VD) and coefficient-of-variation (CV) of DSC.
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Affiliation(s)
- Wu Qiu
- Robarts Research Institute, University of Western Ontario, London, ON, Canada.
| | - Jing Yuan
- Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Eranga Ukwatta
- Robarts Research Institute, University of Western Ontario, London, ON, Canada; Biomedical Engineering Graduate Program, University of Western Ontario, London, ON, Canada
| | - Yue Sun
- Robarts Research Institute, University of Western Ontario, London, ON, Canada; Biomedical Engineering Graduate Program, University of Western Ontario, London, ON, Canada
| | - Martin Rajchl
- Robarts Research Institute, University of Western Ontario, London, ON, Canada; Biomedical Engineering Graduate Program, University of Western Ontario, London, ON, Canada
| | - Aaron Fenster
- Robarts Research Institute, University of Western Ontario, London, ON, Canada; Biomedical Engineering Graduate Program, University of Western Ontario, London, ON, Canada; Medical Biophysics, University of Western Ontario, London, ON, Canada
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93
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Qiu W, Yuan J, Ukwatta E, Tessier D, Fenster A. Three-dimensional prostate segmentation using level set with shape constraint based on rotational slices for 3D end-firing TRUS guided biopsy. Med Phys 2014; 40:072903. [PMID: 23822454 DOI: 10.1118/1.4810968] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Prostate segmentation is an important step in the planning and treatment of 3D end-firing transrectal ultrasound (TRUS) guided prostate biopsy. In order to improve the accuracy and efficiency of prostate segmentation in 3D TRUS images, an improved level set method is incorporated into a rotational-slice-based 3D prostate segmentation to decrease the accumulated segmentation errors produced by the slice-by-slice segmentation method. METHODS A 3D image is first resliced into 2D slices in a rotational manner in both the clockwise and counterclockwise directions. All slices intersect approximately along the rotational scanning axis and have an equal angular spacing. Six to eight boundary points are selected to initialize a level set function to extract the prostate contour within the first slice. The segmented contour is then propagated to the adjacent slice and is used as the initial contour for segmentation. This process is repeated until all slices are segmented. A modified distance regularization level set method is used to segment the prostate in all resliced 2D slices. In addition, shape-constraint and local-region-based energies are imposed to discourage the evolved level set function to leak in regions with weak edges or without edges. An anchor point based energy is used to promote the level set function to pass through the initial selected boundary points. The algorithm's performance was evaluated using distance- and volume-based metrics (sensitivity (Se), Dice similarity coefficient (DSC), mean absolute surface distance (MAD), maximum absolute surface distance (MAXD), and volume difference) by comparison with expert delineations. RESULTS The validation results using thirty 3D patient images showed that the authors' method can obtain a DSC of 93.1% ± 1.6%, a sensitivity of 93.0% ± 2.0%, a MAD of 1.18 ± 0.36 mm, a MAXD of 3.44 ± 0.8 mm, and a volume difference of 2.6 ± 1.9 cm(3) for the entire prostate. A reproducibility experiment demonstrated that the proposed method yielded low intraobserver and interobserver variability in terms of DSC. The mean segmentation time of the authors' method for all patient 3D TRUS images was 55 ± 3.5 s, in addition to 30 ± 5 s for initialization. CONCLUSIONS To address the challenges involved with slice-based 3D prostate segmentation, a level set based method is proposed in this paper. This method is especially developed for a 3D end-firing TRUS guided prostate biopsy system. The extensive experimental results demonstrate that the proposed method is accurate, robust, and computationally efficient.
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Affiliation(s)
- Wu Qiu
- Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario N6A 5K8, Canada.
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Schulz J, Skrøvseth SO, Tømmerås VK, Marienhagen K, Godtliebsen F. A semiautomatic tool for prostate segmentation in radiotherapy treatment planning. BMC Med Imaging 2014; 14:4. [PMID: 24460666 PMCID: PMC3933010 DOI: 10.1186/1471-2342-14-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 01/15/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Delineation of the target volume is a time-consuming task in radiotherapy treatment planning, yet essential for a successful treatment of cancers such as prostate cancer. To facilitate the delineation procedure, the paper proposes an intuitive approach for 3D modeling of the prostate by slice-wise best fitting ellipses. METHODS The proposed estimate is initialized by the definition of a few control points in a new patient. The method is not restricted to particular image modalities but assumes a smooth shape with elliptic cross sections of the object. A training data set of 23 patients was used to calculate a prior shape model. The mean shape model was evaluated based on the manual contour of 10 test patients. The patient records of training and test data are based on axial T1-weighted 3D fast-field echo (FFE) sequences. The manual contours were considered as the reference model. Volume overlap (Vo), accuracy (Ac) (both ratio, range 0-1, optimal value 1) and Hausdorff distance (HD) (mm, optimal value 0) were calculated as evaluation parameters. RESULTS The median and median absolute deviation (MAD) between manual delineation and deformed mean best fitting ellipses (MBFE) was Vo (0.9 ± 0.02), Ac (0.81 ± 0.03) and HD (4.05 ± 1.3)mm and between manual delineation and best fitting ellipses (BFE) was Vo (0.96 ± 0.01), Ac (0.92 ± 0.01) and HD (1.6 ± 0.27)mm. Additional results show a moderate improvement of the MBFE results after Monte Carlo Markov Chain (MCMC) method. CONCLUSIONS The results emphasize the potential of the proposed method of modeling the prostate by best fitting ellipses. It shows the robustness and reproducibility of the model. A small sample test on 8 patients suggest possible time saving using the model.
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Affiliation(s)
- Jörn Schulz
- Department of Mathematics and Statistics, University of Tromsø, 9037 Tromsø, Norway.
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Gunnlaugsson A, Kjellén E, Hagberg O, Thellenberg-Karlsson C, Widmark A, Nilsson P. Change in prostate volume during extreme hypo-fractionation analysed with MRI. Radiat Oncol 2014; 9:22. [PMID: 24410739 PMCID: PMC3901329 DOI: 10.1186/1748-717x-9-22] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 01/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypo-fractionated external beam radiotherapy with narrow CTV-PTV margins is increasingly applied for prostate cancer. This demands a precise target definition and knowledge on target location and extension during treatment. It is unclear how increase in fraction size affects changes in prostate volume during treatment. Our aim was to study prostate volume changes during extreme hypo-fractionation (7 × 6.1 Gy) by using sequential MRIs. METHODS Twenty patients treated with extreme hypo-fractionation were recruited from an on-going prospective randomized phase III trial. An MRI scan was done before start of treatment, at mid treatment and at the end of radiotherapy. The prostate was delineated at each MRI and the volume and maximum extension in left-right, anterior-posterior and cranial-caudal directions were measured. RESULTS There was a significant increase in mean prostate volume (14%) at mid treatment as compared to baseline. The prostate volume remained enlarged (9%) at the end of radiotherapy. Prostate swelling was most pronounced in the anterior-posterior and cranial-caudal directions. CONCLUSIONS Extreme hypo-fractionation induced a significant prostate swelling during treatment that was still present at the time of last treatment fraction. Our results indicate that prostate swelling is an important factor to take into account when applying treatment margins during short extreme hypo-fractionation, and that tight margins should be applied with caution.
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96
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Fully automated prostate segmentation on MRI: comparison with manual segmentation methods and specimen volumes. AJR Am J Roentgenol 2014; 201:W720-9. [PMID: 24147502 DOI: 10.2214/ajr.12.9712] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of our study was to compare calculated prostate volumes derived from tridimensional MR measurements (ellipsoid formula), manual segmentation, and a fully automated segmentation system as validated by actual prostatectomy specimens. MATERIALS AND METHODS Ninety-eight consecutive patients (median age, 60.6 years; median prostate-specific antigen [PSA] value, 6.85 ng/mL) underwent triplane T2-weighted MRI on a 3-T magnet with an endorectal coil while undergoing diagnostic workup for prostate cancer. Prostate volume estimates were determined using the formula for ellipsoid volume based on tridimensional measurements, manual segmentation of triplane MRI, and automated segmentation based on normalized gradient fields cross-correlation and graph-search refinement. Estimates of prostate volume based on ellipsoid volume, manual segmentation, and automated segmentation were compared with prostatectomy specimen volumes. Prostate volume estimates were compared using the Pearson correlation coefficient and linear regression analysis. The Dice similarity coefficient was used to quantify spatial agreement between manual segmentation and automated segmentation. RESULTS The Pearson correlation coefficient revealed strong positive correlation between prostatectomy specimen volume and prostate volume estimates derived from manual segmentation (R = 0.89-0.91, p < 0.0001) and automated segmentation (R = 0.88-0.91, p < 0.0001). No difference was observed between manual segmentation and automated segmentation. Mean partial and full Dice similarity coefficients of 0.92 and 0.89, respectively, were achieved for axial automated segmentation. CONCLUSION Prostate volume estimates obtained with a fully automated 3D segmentation tool based on normalized gradient fields cross-correlation and graph-search refinement can yield highly accurate prostate volume estimates in a clinically relevant time of 10 seconds. This tool will assist in developing a broad range of applications including routine prostate volume estimations, image registration, biopsy guidance, and decision support systems.
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Khalvati F. Automated consensus contour building for prostate MRI. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2014; 2014:5534-5537. [PMID: 25571248 DOI: 10.1109/embc.2014.6944880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Inter-observer variability is the lack of agreement among clinicians in contouring a given organ or tumour in a medical image. The variability in medical image contouring is a source of uncertainty in radiation treatment planning. Consensus contour of a given case, which was proposed to reduce the variability, is generated by combining the manually generated contours of several clinicians. However, having access to several clinicians (e.g., radiation oncologists) to generate a consensus contour for one patient is costly. This paper presents an algorithm that automatically generates a consensus contour for a given case using the atlases of different clinicians. The algorithm was applied to prostate MR images of 15 patients manually contoured by 5 clinicians. The automatic consensus contours were compared to manual consensus contours where a median Dice similarity coefficient (DSC) of 88% was achieved.
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98
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Crehange G, Krishnamurthy D, Cunha JA, Pickett B, Kurhanewicz J, Hsu IC, Gottschalk AR, Shinohara K, Roach M, Pouliot J. Cold spot mapping inferred from MRI at time of failure predicts biopsy-proven local failure after permanent seed brachytherapy in prostate cancer patients: implications for focal salvage brachytherapy. Radiother Oncol 2013; 109:246-50. [PMID: 24231238 DOI: 10.1016/j.radonc.2013.10.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/22/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf. MATERIAL AND METHODS Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF. RESULTS pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold. CONCLUSIONS Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.
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Affiliation(s)
- Gilles Crehange
- Department of Radiation Oncology, Helen Diller Family Comprehensive Cancer Center, UCSF, San Francisco, USA; Department of Radiation Oncology, Dijon University Hospital, France.
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Even AJG, Nuver TT, Westendorp H, Hoekstra CJ, Slump CH, Minken AW. High-dose-rate prostate brachytherapy based on registered transrectal ultrasound and in-room cone-beam CT images. Brachytherapy 2013; 13:128-36. [PMID: 24041955 DOI: 10.1016/j.brachy.2013.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 07/25/2013] [Accepted: 08/01/2013] [Indexed: 11/25/2022]
Abstract
PURPOSE To present a high-dose-rate (HDR) brachytherapy procedure for prostate cancer using transrectal ultrasound (TRUS) to contour the regions of interest and registered in-room cone-beam CT (CBCT) images for needle reconstruction. To characterize the registration uncertainties between the two imaging modalities and explore the possibility of performing the procedure solely on TRUS. METHODS AND MATERIALS Patients were treated with a TRUS/CBCT-based HDR brachytherapy procedure. For 100 patients, dosimetric results were analyzed. For 40 patients, registration uncertainties were examined by determining differences in fiducial marker positions on TRUS and registered CBCT. The accuracy of needle reconstruction on TRUS was investigated by determining the position differences of needle tips on TRUS and CBCT. The dosimetric impact of reregistration and needle reconstruction on TRUS only was studied for 8 patients. RESULTS The average prostate V100 was 97.8%, urethra D10 was 116.3%, and rectum D1 cc was 66.4% of the prescribed dose. For 85% of the patients, registration inaccuracies were within 3 mm. Large differences were found between needle tips on TRUS and CBCT, especially in cranial-caudal direction, with a maximum of 10.4 mm. Reregistration resulted in a maximum V100 reduction of 0.9%, whereas needle reconstruction on TRUS only gave a maximum reduction of 9.4%. CONCLUSIONS HDR prostate brachytherapy based on TRUS combined with CBCT is an accurate method. Registration uncertainties, and consequently dosimetric inaccuracies, are small compared with the uncertainties of performing the procedure solely based on static TRUS images. CBCT imaging is a requisite in our current procedure.
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Affiliation(s)
- Aniek J G Even
- Department of Medical Physics, Radiotherapeutic Institute RISO, Deventer, The Netherlands; MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Tonnis T Nuver
- Department of Medical Physics, Radiotherapeutic Institute RISO, Deventer, The Netherlands; Department of Radiation Oncology, Radiotherapeutic Institute RISO, Deventer, The Netherlands.
| | - Hendrik Westendorp
- Department of Medical Physics, Radiotherapeutic Institute RISO, Deventer, The Netherlands; Department of Radiation Oncology, Radiotherapeutic Institute RISO, Deventer, The Netherlands
| | - Carel J Hoekstra
- Department of Radiation Oncology, Radiotherapeutic Institute RISO, Deventer, The Netherlands
| | - Cornelis H Slump
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - André W Minken
- Department of Medical Physics, Radiotherapeutic Institute RISO, Deventer, The Netherlands; Department of Radiation Oncology, Radiotherapeutic Institute RISO, Deventer, The Netherlands
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Hanvey S, McJury M, Tho LM, Glegg M, Thomson M, Grose D, James A, Rizwanullah M, Paterson C, Foster J. The influence of MRI scan position on patients with oropharyngeal cancer undergoing radical radiotherapy. Radiat Oncol 2013; 8:129. [PMID: 23714579 PMCID: PMC3681609 DOI: 10.1186/1748-717x-8-129] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study was to demonstrate how magnetic resonance imaging (MRI) patient position protocols influence registration quality in patients with oropharyngeal cancer undergoing radical radiotherapy and the consequences for gross tumour volume (GTV) definition and radiotherapy planning. Methods and materials Twenty-two oropharyngeal patients underwent a computed tomography (CT), a diagnostic MRI (MRID) and an MRI in the radiotherapy position within an immobilization mask (MRIRT). Clinicians delineated the GTV on the CT viewing the MRID separately (GTVC); on the CT registered to MRID (GTVD) and on the CT registered to MRIRT (GTVRT). Planning target volumes (PTVs) were denoted similarly. Registration quality was assessed by measuring disparity between structures in the three set-ups. Volumetric modulated arc therapy (VMAT) radiotherapy planning was performed for PTVC, PTVD and PTVRT. To determine the dose received by the reference PTVRT, we optimized for PTVC and PTVD while calculating the dose to PTVRT. Statistical significance was determined using the two-tailed Mann–Whitney or two-tailed paired student t-tests. Results A significant improvement in registration accuracy was found between CT and MRIRT versus the MRID measuring distances from the centre of structures (geometric mean error of 2.2 mm versus 6.6 mm). The mean GTVC (44.1 cm3) was significantly larger than GTVD (33.7 cm3, p value = 0.027) or GTVRT (30.5 cm3, p value = 0.014). When optimizing the VMAT plans for PTVC and investigating the mean dose to PTVRT neither the dose to 99% (58.8%) nor 95% of the PTV (84.7%) were found to meet the required clinical dose constraints of 90% and 95% respectively. Similarly, when optimizing for PTVD the mean dose to PTVRT did not meet clinical dose constraints for 99% (14.9%) nor 95% of the PTV (66.2%). Only by optimizing for PTVRT were all clinical dose constraints achieved. Conclusions When oropharyngeal patients MRI scans are performed in the radiotherapy position there are significant improvements in CT-MR image registration, target definition and PTV dose coverage.
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