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Kennedy AC, Douglass MJJ, Santos AMC. Being certain about uncertainties: a robust evaluation method for high-dose-rate prostate brachytherapy treatment plans including the combination of uncertainties. Phys Eng Sci Med 2023; 46:1115-1130. [PMID: 37249825 PMCID: PMC10480262 DOI: 10.1007/s13246-023-01279-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 05/12/2023] [Indexed: 05/31/2023]
Abstract
In high-dose-rate (HDR) prostate brachytherapy the combined effect of uncertainties cause a range of possible dose distributions deviating from the nominal plan, and which are not considered during treatment plan evaluation. This could lead to dosimetric misses for critical structures and overdosing of organs at risk. A robust evaluation method to assess the combination of uncertainties during plan evaluation is presented and demonstrated on one HDR prostate ultrasound treatment plan retrospectively. A range of uncertainty scenarios are simulated by changing six parameters in the nominal plan and calculating the corresponding dose distribution. Two methods are employed to change the parameters, a probabilistic approach using random number sampling to evaluate the likelihood of variation in dose distributions, and a combination of the most extreme possible values to access the worst-case dosimetric outcomes. One thousand probabilistic scenarios were run on the single treatment plan with 43.2% of scenarios passing seven of the eight clinical objectives. The prostate D90 had a standard deviation of 4.4%, with the worst case decreasing the dose by up to 27.2%. The urethra D10 was up to 29.3% higher than planned in the worst case. All DVH metrics in the probabilistic scenarios were found to be within acceptable clinical constraints for the plan under statistical tests for significance. The clinical significance of the results from the robust evaluation method presented on any individual treatment plan needs to be compared in the context of a historical data set that contains patient outcomes with robustness analysis data to ascertain a baseline acceptance.
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Affiliation(s)
- Andrew C. Kennedy
- School of Physical Sciences, University of Adelaide, Adelaide, SA 5005 Australia
| | - Michael J. J. Douglass
- School of Physical Sciences, University of Adelaide, Adelaide, SA 5005 Australia
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, SA 5000 Australia
- Australian Bragg Centre for Proton Therapy and Research, North Terrace, Adelaide, SA 5000 Australia
| | - Alexandre M. C. Santos
- School of Physical Sciences, University of Adelaide, Adelaide, SA 5005 Australia
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, SA 5000 Australia
- Australian Bragg Centre for Proton Therapy and Research, North Terrace, Adelaide, SA 5000 Australia
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Doyle AJ, Cody D, Knight S, King DM, Sullivan FJ, Browne JE. Contrast-Specific Spherical Lesion Phantoms and Ancillary Analysis Software for the Objective Evaluation of Transrectal Ultrasound System Contrast Detectability. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1615-1627. [PMID: 35659496 DOI: 10.1016/j.ultrasmedbio.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 06/15/2023]
Abstract
Brachytherapy is an efficacious treatment option because of its benefits for patient recovery, dose localization and conformity, but these favorable outcomes can be ensured only if the transrectal ultrasound (TRUS) system is optimized for the specific application of ultrasound-guided prostate brachytherapy. The ability to delineate the prostate from surrounding tissue during TRUS-guided prostate brachytherapy is vital for treatment planning, and consequently, so is the contrast resolution. This study describes the development of task-specific contrast-detail phantoms with clinically relevant contrast and spherical target sizes for contrast-detail performance evaluation of TRUS systems used in the brachytherapy procedure. The procedure for objective assessment of the contrast detectability of the TRUS systems is also described; a program was developed in MATLAB (R2017a, The MathWorks, Natick, MA, USA) to quantitatively analyze image quality in terms of the lesion signal-to-noise ratio (LSNR) and validated with representative control test images. The LSNR of the Hitachi EUB-7500A (2013, Hitachi, Ltd, Tokyo, Japan) TRUS system was measured on sagittal and transverse TRUS images of the contrast-detail phantoms described in this work. Results revealed the efficacy of the device as an image quality evaluation tool and the impact of the size, depth and relative contrast of the targets to the surrounding tissue on the contrast detectability of a TRUS system for both transducer arrays. The MATLAB program objectively measured the contrast detectability of the TRUS system and has the potential to determine optimized imaging parameters that could be designed as part of standardization of the imaging protocol used in TRUS-guided prostate brachytherapy for prostate cancer.
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Affiliation(s)
- Andrea Jane Doyle
- School of Physics and Clinical and Optometric Sciences, Medical Ultrasound Physics and Technology Group, Centre for Industrial and Engineering Optics, Focas, Technological University Dublin, Dublin, Ireland; RCSI SIM Centre for Simulation Education and Research, RCSI University of Medicine and Health Sciences, Dublin, Ireland.
| | - Dervil Cody
- School of Physics and Clinical and Optometric Sciences, Medical Ultrasound Physics and Technology Group, Centre for Industrial and Engineering Optics, Focas, Technological University Dublin, Dublin, Ireland
| | - Silvin Knight
- School of Medicine, Trinity College Dublin, University of Dublin, Dublin, Ireland
| | | | - Francis J Sullivan
- Prostate Cancer Institute, National University of Ireland Galway, Galway, Ireland; Department of Radiotherapy, Galway Clinic, Galway, Ireland
| | - Jacinta E Browne
- School of Physics and Clinical and Optometric Sciences, Medical Ultrasound Physics and Technology Group, Centre for Industrial and Engineering Optics, Focas, Technological University Dublin, Dublin, Ireland; Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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Anvari A, Forsberg F, Samir AE. A Primer on the Physical Principles of Tissue Harmonic Imaging. Radiographics 2015; 35:1955-64. [DOI: 10.1148/rg.2015140338] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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