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Ballhausen H, Belka C, Li M. Prostate intra-fraction motion recorded by transperineal ultrasound. Sci Data 2024; 11:504. [PMID: 38755158 PMCID: PMC11099185 DOI: 10.1038/s41597-024-03365-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/09/2024] [Indexed: 05/18/2024] Open
Abstract
Infra-fraction motion of the prostate was recorded during 3.423 fractions of image guided radiotherapy (IGRT) in 191 patients, 14 of which were treated by intensity modulated radiation therapy (IMRT), and 177 of which were treated by volumetric arc therapy (VMAT). The prostate was imaged by three-dimensional and time-resolved transperineal ultrasound (4D-US) of type Clarity by Elekta AB, Stockholm, Sweden. The prostate volume was registered and the prostate position (center of volume) was recorded at a frequency of 2.0 samples per second. This raw data set contains a total of 1.985.392 prostate and patient couch positions over a time span of 272 hours, 52 minutes and 34 seconds of life radiotherapy as exported by the instrument software. This data set has been used for the validation of models of prostate intra-fraction motion and for the estimation of the dosimetric impact of actual intra-fraction motion on treatment quality and side effects. We hope that this data set may be reused by other groups for similar purposes.
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Affiliation(s)
- Hendrik Ballhausen
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Munich, Germany.
| | - Claus Belka
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, Munich, Germany
- Bavarian Cancer Research Center (BZKF), Munich, Germany
| | - Minglun Li
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Munich, Germany
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Li Y, Gong Z, Liu M, Li H, Gao H, Guo C, Yu L, Zhu C, Sun Z, Sun L, Xu H, He X. 3D-US and CBCT Dual-guided Radiotherapy for Postoperative Uterine Malignancy: A Primary Workflow Set-up. Technol Cancer Res Treat 2023; 22:15330338231212082. [PMID: 37993995 PMCID: PMC10666818 DOI: 10.1177/15330338231212082] [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: 03/03/2023] [Revised: 09/09/2023] [Accepted: 09/26/2023] [Indexed: 11/24/2023] Open
Abstract
Introduction: The consistency of clinical target volume is essential to guiding radiotherapy with precision for postoperative uterine malignancy patients. By introducing a three-dimensional ultrasound system (3D-US) into image-guided radiation therapy (IGRT), this study was designed to investigate the initial workflow set-up, the therapeutic potential, and the adverse events of 3D-US and cone-beam computed tomography (CBCT) dual-guided radiotherapy in postoperative uterine malignancy treatment. Methods: From April 2021 to December 2021, postoperative uterine malignancy patients were instructed to follow the previously standard protocol of daily radiation treatment, particularly a 3D-US (Clarity system) guiding was involved before CBCT. Soft-tissue-based displacements resulting from the additional US-IGRT were acquired in the LT (left)/RT (right), ANT (anterior)/POST (posterior), and SUP (superior)/INF(inferior) directions of the patient before fractional treatment. Displacement distributions before and after treatment either from 3D-US or from CBCT were also estimated and compared subsequently, and the urinary and rectal toxicity was further evaluated. Results: All the patients completed radiation treatment as planned. The assessment of 170 scans resulted in a mean displacement of (0.17 ± 0.24) cm, (0.19 ± 0.23) cm, (0.22 ± 0.26) cm for bladder in LT/RT, ANT/POST, and SUP/INF directions. A mean deviation of (0.26 ± 0.22) cm, (0.58 ± 0.5) cm, and (0.3 ± 0.23) cm was also observed for the bladder centroid between the CBCT and computed tomography -simulation images in three directions. Paired comparison between these two guidance shows that the variations from 3D-US are much smaller than those from CBCT in three directions, especially in ANT/POST and SUP/INF directions with significance (P = 0.000, 0.001, respectively). During treatment, and 0, 3, 6, 9, and 12 months after treatment, there was no severe urinary and rectal toxicity happened. Conclusion: A primary workflow of 3D-US and CBCT dual-guided radiotherapy has been established, which showed great therapeutic potential with mild to moderate urinary and rectal toxicity for postoperative uterine malignancy patients. But the clinical outcomes of this non-invasive technique need to be investigated further.
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Affiliation(s)
- Yang Li
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Zhen Gong
- Department of Gynecology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Mengyu Liu
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Huixin Li
- Department of Gynecology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China
| | - Han Gao
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Chang Guo
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Le Yu
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Chenjing Zhu
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Zhihua Sun
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Li Sun
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Hanzi Xu
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
| | - Xia He
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
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The ProMotion LMU dataset (2022 edition), prostate intra-fraction motion recorded by transperineal ultrasound. Sci Data 2022; 9:455. [PMID: 35908072 PMCID: PMC9338943 DOI: 10.1038/s41597-022-01583-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
Infra-fraction motion of the prostate was recorded during 2.385 fractions of image guided radiotherapy (IGRT) in 126 patients, 14 of which were treated by intensity modulated radiation therapy (IMRT), and 112 of which were treated by volumetric arc therapy (VMAT). The prostate was imaged by three-dimensional and time-resolved transperineal ultrasound (4D-US) of type Clarity by Elekta, Stockholm, Sweden. The prostate volume was registered and the prostate position (center of volume) was recorded at a frequency of 2.0 samples per second. This raw data set contains a total of 1.138.024 prostate and patient couch positions over a time span of 158 hours, 25 minutes and 50 seconds of life radiotherapy as exported by the instrument software. This data set has been used for the validation of models of prostate intra-fraction motion and for the estimation of the dosimetric impact of actual intra-fraction motion on treatment quality and side effects. We hope that this data set may be reused by other groups for similar purposes. Measurement(s) | intrafraction motion of the prostate | Technology Type(s) | transperineal ultrasound (4D) | Sample Characteristic - Organism | Homo sapiens | Sample Characteristic - Environment | hospital | Sample Characteristic - Location | Germany |
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Ballhausen H, Li M, Belka C. The ProMotion LMU dataset, prostate intra-fraction motion recorded by transperineal ultrasound. Sci Data 2019; 6:269. [PMID: 31712658 PMCID: PMC6848118 DOI: 10.1038/s41597-019-0280-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/14/2019] [Indexed: 11/10/2022] Open
Abstract
Intra-fraction motion of the prostate was recorded during 721 fractions of image guided radiotherapy (IGRT) in 28 patients, 14 of which were treated by intensity modulated radiation therapy (IMRT), and 14 of which were treated by volumetric arc therapy (VMAT). The prostate was imaged by three-dimensional and time-resolved transperineal ultrasound (4D-US) of type Clarity by Elekta, Stockholm, Sweden. The prostate volume was registered and the prostate position (center of volume) was recorded at a frequency of 1.6 samples per second. This raw data set contains a total of 380.199 prostate and patient couch positions over a time span of 53 hours, 47 minutes and 29 seconds of life radiotherapy as exported by the instrument software. This data set has been used for the validation of models of prostate intra-fraction motion and for the estimation of the dosimetric impact of actual intra-fraction motion on treatment quality and side effects. We hope that this data set may be reused by other groups for similar purposes.
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Affiliation(s)
- Hendrik Ballhausen
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Minglun Li
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Claus Belka
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
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Zhou S, Luo L, Li J, Lin M, Chen L, Shao J, Lu S, Ma Y, Zhang Y, Chen W, Liu M, Liu S, He L. Analyses of the factors influencing the accuracy of three-dimensional ultrasound in comparison with cone-beam CT in image-guided radiotherapy for prostate cancer with or without pelvic lymph node irradiation. Radiat Oncol 2019; 14:22. [PMID: 30696488 PMCID: PMC6352439 DOI: 10.1186/s13014-019-1217-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/08/2019] [Indexed: 11/16/2022] Open
Abstract
Background Three-dimensional ultrasound (3DUS) is an attractive option in image-guided radiotherapy (IGRT) for prostate cancer (PCa) patients. However, the potential factors influencing the accuracy of 3DUS in comparison with cone-beam CT (CBCT) in IGRT for PCa patients haven’t been clearly identified. Methods The differences between US/US and CBCT/CT registrations were analyzed over 586 and 580 sessions for 24 and 25 PCa patients treated with or without pelvic lymph node irradiation, respectively. The clinical factors that may influence registration differences were also evaluated. Results The average discrepancies between US/US and CBCT/CT registrations were − 0.28 ± 5.28 mm, − 0.16 ± 3.48 mm, and − 0.47 ± 4.31 mm in the superior-inferior (SI), left-right (LR), and anterior-posterior (AP) directions, respectively. The discrepancies were respectively less than 5 mm longitudinally, laterally, and vertically in 64.4 and 70.1%, 84.9 and 89.2%, and 75.9 and 79.1% of the patients treated with or without pelvic lymph node irradiation, respectively. The registration differences were significantly smaller at least in one direction in patients younger than 70 years, without pelvic lymph node irradiation, guided by transperineal ultrasonography and had a bladder volume smaller than 300 mL. Conclusions Age, irradiated regions, 3DUS modality, and bladder volume are important factors that may influence the differences between US/US and CBCT/CT registrations. 3DUS guidance is more feasible for younger PCa patients with a better control of bladder volume during the treatment and those who did not undergo pelvic lymph node irradiation. Electronic supplementary material The online version of this article (10.1186/s13014-019-1217-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sha Zhou
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Liling Luo
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Jibin Li
- Department of Clinical Research, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Maosheng Lin
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Li Chen
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Jianhui Shao
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Shipei Lu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Yaru Ma
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Yingting Zhang
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Wenfen Chen
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Mengzhong Liu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China
| | - Shiliang Liu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China.
| | - Liru He
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, No. 651, Dongfeng Road East, Guangzhou, 510060, China.
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Comparison of 2 transabdominal ultrasound image guidance techniques for prostate and prostatic fossa radiation therapy. Pract Radiat Oncol 2017; 7:e99-e107. [PMID: 28274407 DOI: 10.1016/j.prro.2016.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/09/2016] [Accepted: 07/05/2016] [Indexed: 11/24/2022]
Abstract
PURPOSE Our clinic is a long-term user of a first-generation transabdominal (TA) biplanar (2.5-dimensional [2.5D]) ultrasound image guidance (USIG) system for prostate cancer treatments. We are also an early adopter and development partner for a new, second-generation, fully 3D USIG system that allows for volumetric TA localization of the prostate. This new system has been evaluated at our institution by direct comparison with the previously established first-generation TA method for prostate alignment. METHODS AND MATERIALS We compared the 2 TA-USIG methods on the same subjects and same treatment sessions. A total of 1428 fractions delivered to 41 treated patients (16 intact prostate, 25 fossa) were analyzed regarding the agreement of alignments between the 2 US positioning systems. Patients were first aligned to tattoos using treatment room lasers. TA-USIG using the 3D system was then performed to align contours derived during the computed tomography simulation process to their corresponding daily US-visualized structures. The US-3D system image guidance shifts were performed and recorded as the "initial" shifts. A 2.5D system alignment was then immediately performed using the same computed tomography derived reference contours and the indicated shifts, relative to the 3D system, were recorded as the difference between the 2 alignment methods. RESULTS The average difference between the 2 TA-USIG alignments for all patients was 0.4 ± 0.7 mm, 0.7 ± 0.9 mm, and 0.5 ± 0.9 mm in the left-right, anteroposterior, and superoinferior directions, respectively. No significant difference in system agreement between intact prostate versus fossa patients was observed. CONCLUSION Our comparison of an established 2.5D USIG method with a newer, fully 3D approach for prostate alignment of 41 different patients (1428 fractions) shows excellent agreement with each other, despite the nontrivial difference in imaging approaches. This shows that the 2 specific USIG approaches yield results that are consistent with each other, and that the USIG modality yields consistent results within the modality.
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Li M, Hegemann NS, Manapov F, Kolberg A, Thum PD, Ganswindt U, Belka C, Ballhausen H. Prefraction displacement and intrafraction drift of the prostate due to perineal ultrasound probe pressure. Strahlenther Onkol 2017; 193:459-465. [DOI: 10.1007/s00066-017-1105-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/24/2017] [Indexed: 11/30/2022]
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Comparison of prostate positioning guided by three-dimensional transperineal ultrasound and cone beam CT. Strahlenther Onkol 2016; 193:221-228. [PMID: 27928626 DOI: 10.1007/s00066-016-1084-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/09/2016] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The accuracy of a transperineal three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to fiducial- and bone-based positioning in kV cone beam computed tomography (CBCT) during definitive radiotherapy of prostate cancer. METHODS Each of the 7 patients had three fiducial markers implanted into the prostate before treatment. Prostate positioning was simultaneously measured by 3DUS and CBCT before each fraction. In total, 177 pairs of 3DUS and CBCT scans were collected. Bone-match and seed-match were performed for each CBCT. Using seed-match as a reference, the accuracy of 3DUS and bone-match was evaluated. Systematic and random errors as well as optimal setup margins were calculated for 3DUS and bone-match. RESULTS The discrepancy between 3DUS and seed-match in CBCT (average ± standard deviation) was 0.0 ± 1.7 mm laterally, 0.2 ± 2.0 mm longitudinally, and 0.3 ± 1.7 mm vertically. Using seed-match as a reference, systematic errors for 3DUS were 1.2 mm, 1.1 mm, and 0.9 mm; and random errors were 1.4 mm, 1.8 mm, and 1.6 mm, on lateral, longitudinal, and vertical axes, respectively. By analogy, the difference of bone-match to seed-match was 0.1 ± 1.1 mm laterally, 1.3 ± 3.8 mm longitudinally, and 1.3 ± 4.5 mm vertically. Systematic errors were 0.5 mm, 2.2 mm, and 2.6 mm; and random errors were 1.0 mm, 3.1 mm, and 3.9 mm on lateral, longitudinal, and vertical axes, respectively. The accuracy of 3DUS was significantly higher than that of bone-match on longitudinal and vertical axes, but not on the lateral axis. CONCLUSION Image-guided radiotherapy of prostate cancer based on transperineal 3DUS was feasible, with overall small discrepancy to seed-match in CBCT in this retrospective study. Compared to bone-match, transperineal 3DUS achieved higher accuracy on longitudinal and vertical axes.
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Ballhausen H, Ganswindt U, Belka C, Li M. Intra-fraction motion of the prostate is not increased by patient couch shifts. Radiat Oncol 2016; 11:49. [PMID: 27005431 PMCID: PMC4804511 DOI: 10.1186/s13014-016-0620-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/11/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND During a fraction of external beam radiotherapy for prostate cancer, a mismatch between target volume and dose coverage may accumulate over time due to intra-fraction motion. One way to remove the residual error is to perform a couch shift in opposite direction. In principle, such couch shifts could cause secondary displacements of the patient and prostate. Hence it is interesting to investigate if couch shifts might amplify intra-fraction motion. FINDINGS Intra-fraction motion of the prostate and patient couch position were simultaneously recorded during 359 fractions in 15 patients. During this time, a total of 22 couch shifts of up to 31.5 mm along different axes were recorded. Prostate position and couch position were plotted before, during and after each couch shift. There was no visible impact of couch shifts on prostate motion. The standard deviation of prostate position was calculated before, during and after each couch shift. The standard deviation did not significantly increase during couch shifts (by 3 % on average, p = 0.88) and even slightly decreased after a couch shift (by 37 % on average; p = 0.02). CONCLUSIONS Shifts of the patient couch did not adversely affect the motion of the prostate relative to the patient couch. Hence, shifts of the patient couch may be a viable way to correct the position of the prostate relative to the dose distribution.
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Affiliation(s)
- Hendrik Ballhausen
- University Hospital of LMU Munich, Department of Radiation Oncology, Marchioninistraße 15, 81377, Munich, Germany.
| | - Ute Ganswindt
- University Hospital of LMU Munich, Department of Radiation Oncology, Marchioninistraße 15, 81377, Munich, Germany
| | - Claus Belka
- University Hospital of LMU Munich, Department of Radiation Oncology, Marchioninistraße 15, 81377, Munich, Germany
| | - Minglun Li
- University Hospital of LMU Munich, Department of Radiation Oncology, Marchioninistraße 15, 81377, Munich, Germany
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Ballhausen H, Ballhausen BD, Lachaine M, Li M, Parodi K, Belka C, Reiner M. Surface refraction of sound waves affects calibration of three-dimensional ultrasound. Radiat Oncol 2015; 10:119. [PMID: 26014494 PMCID: PMC4450514 DOI: 10.1186/s13014-015-0424-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/21/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Three-dimensional ultrasound (3D-US) is used in planning and treatment during external beam radiotherapy. The accuracy of the technique depends not only on the achievable image quality in clinical routine, but also on technical limitations of achievable precision during calibration. Refraction of ultrasound waves is a known source for geometric distortion, but such an effect was not expected in homogenous calibration phantoms. However, in this paper we demonstrate that the discontinuity of the refraction index at the phantom surface may affect the calibration unless the ultrasound probe is perfectly perpendicular to the phantom. METHODS A calibration phantom was repeatedly scanned with a 3D-US system (Elekta Clarity) by three independent observers. The ultrasound probe was moved horizontally at a fixed angle in the sagittal plane. The resulting wedge shaped volume between probe and phantom was filled with water to couple in the ultrasound waves. Because the speed of sound in water was smaller than the speed of sound in Zerdine, the main component of the phantom, the angle of the ultrasound waves inside the phantom increased. This caused an apparent shift in the calibration features which was recorded as a function of the impeding angle. To confirm the magnitude and temperature dependence, the experiment was repeated by two of the observers with a mixture of ice and water at 0 °C and with thermalized tap water at 21 °C room temperature. RESULTS During the first series of measurements, a linear dependency of the displacements dx of the calibration features on the angle α of the ultrasound probe was observed. The three observers recorded significantly nonzero (p < 0.0001) and very consistent slopes of dx/dα of 0.12, 0.12, and 0.13 mm/°, respectively.. At 0 °C water temperature, the slope increased to 0.18 ± 0.04 mm/°. This matched the prediction of Snell's law of 0.185 mm/° for a speed of sound of 1,402 m/s at the melting point of ice. At 21 °C, slopes of 0.11 and 0.12 mm/° were recorded in agreement with the first experiment at about room temperature. The difference to the theoretical expectation of 0.07 mm/° was not significant (p = 0.09). CONCLUSIONS The surface refraction of sound waves my affect the calibration of three-dimensional ultrasound. The temperature dependence of the effect rules out alternative explanations for the observed shifts in calibration. At room temperature and for a structure that is 10 cm below the water-phantom interface, a tilt of the ultrasound probe of 10° may result in a position reading that is off by more than half a millimeter. Such errors are of the order of other relevant errors typically encountered during the calibration of a 3D-US system. Hence, care must be taken not to tilt the ultrasound probe during calibration.
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Affiliation(s)
- Hendrik Ballhausen
- Department of Radiation Oncology, University Hospital of Ludwig-Maximilians-University, Marchioninistraße 15, 81377, Munich, Germany.
| | | | | | - Minglun Li
- Department of Radiation Oncology, University Hospital of Ludwig-Maximilians-University, Marchioninistraße 15, 81377, Munich, Germany.
| | - Katia Parodi
- Department of Experimental Physics, Medical Physics, Ludwig-Maximilians-University, Am Coulombwall 1, 85748, Garching, Germany.
| | - Claus Belka
- Department of Radiation Oncology, University Hospital of Ludwig-Maximilians-University, Marchioninistraße 15, 81377, Munich, Germany.
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital of Ludwig-Maximilians-University, Marchioninistraße 15, 81377, Munich, Germany.
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Li M, Ballhausen H, Hegemann NS, Ganswindt U, Manapov F, Tritschler S, Roosen A, Gratzke C, Reiner M, Belka C. A comparative assessment of prostate positioning guided by three-dimensional ultrasound and cone beam CT. Radiat Oncol 2015; 10:82. [PMID: 25890013 PMCID: PMC4465303 DOI: 10.1186/s13014-015-0380-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/16/2015] [Indexed: 12/25/2022] Open
Abstract
Background The accuracy of the Elekta Clarity™ three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to seed- and bone-based positioning in kilo-voltage cone-beam computed tomography (CBCT) during a definitive radiotherapy. Methods The prostate positioning of 6 patients, with fiducial markers implanted into the prostate, was controlled by 3DUS and CBCT. In total, 78 ultrasound scans were performed trans-abdominally and compared to bone-matches and seed-matches in CBCT scans. Setup errors detected by the different modalities were compared. Systematic and random errors were analysed, and optimal setup margins were calculated. Results The discrepancy between 3DUS and seed-match in CBCT was −0.2 ± 2.7 mm laterally, −1.9 ± 2.3 mm longitudinally and 0.0 ± 3.0 mm vertically and significant only in longitudinal direction. Using seed-match as reference, systematic errors of 3DUS were 1.3 mm laterally, 0.8 mm longitudinally and 1.4 mm vertically, and random errors were 2.5 mm laterally, 2.3 mm longitudinally, and 2.7 mm vertically. No significant difference could be detected for 3DUS in comparison to bone-match in CBCT. Conclusions 3DUS is feasible for image guidance for patients with prostate cancer and appears comparable to CBCT based image guidance in the retrospective study. While 3DUS offers some distinct advantages such as no need of invasive fiducial implantation and avoidance of extra radiation, its disadvantages include the operator dependence of the technique and dependence on sufficient bladder filling. Further study of 3DUS for image guidance in a large patient cohort is warranted.
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Affiliation(s)
- Minglun Li
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Hendrik Ballhausen
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Nina-Sophie Hegemann
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Ute Ganswindt
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Farkhad Manapov
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Stefan Tritschler
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Alexander Roosen
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Christian Gratzke
- Department of Urology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
| | - Claus Belka
- Department of Radiation Oncology, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany.
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Ballhausen H, Hieber S, Li M, Parodi K, Belka C, Reiner M. Linearity of patient positioning detection : a phantom study of skin markers, cone beam computed tomography, and 3D ultrasound. Strahlenther Onkol 2015; 191:442-7. [PMID: 25633164 DOI: 10.1007/s00066-015-0811-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 01/07/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Three-dimensional ultrasound (3D-US) is a modality complementary to kilovoltage cone beam computed tomography (kV-CBCT) and skin markers for patient positioning detection. This study compares the linearity of evaluations based on measurements using a modern 3D-US system (Elekta Clarity®; Elekta, Stockholm, Sweden), a kV-CBCT system (Elekta iView®), and skin markers. MATERIALS AND METHODS An investigator deliberately displaced a multimodal phantom by up to ± 30 mm along different axes. The following data points were acquired: 27 along the lateral axis, 29 along the longitudinal axis, 27 along the vertical axis, and 27 along the space diagonal. At each of these 110 positions, the displacements according to skin' markers were recorded and scans were performed using both 3D-US and kV-CBCT. Shifts were detected by matching bony anatomy or soft tissue density to a reference planning CT in the case of kV-CBCT and for 3D-US, by matching ultrasound volume data to a reference planning volume. A consensus value was calculated from the average of the four modalities. With respect to this consensus value, the linearity (offset and regression coefficient, i.e., slope), average offset, systematic error, and random error of all four modalities were calculated for each axis. RESULTS Linearity was similar for all four modalities, with regression coefficients between 0.994 and 1.012, and all offsets below 1 mm. The systematic errors of skin markers and 3D-US were higher than for kV-CBCT, but random errors were similar. In particular, 3D-US demonstrated an average offset of 0.36 mm to the right, 0.08 mm inferiorly, and 0.15 mm anteriorly; the systematic error was 0.36 mm laterally, 0.35 mm longitudinally, and 0.22 mm vertically; the random error was 0.15 mm laterally, 0.30 mm longitudinally, and 0.12 mm vertically. A total of 109 out of 110 (99 %) 3D-US measurements were within 1 mm of the consensus value on either axis. CONCLUSION The linearity of 3D-US was no worse than that of skin markers or kV-CBCT. Average offsets, systematic errors, and random errors were all below 1 mm. Optimal margins in the order of 1 mm could be achieved in the controlled laboratory setting of this phantom study.
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Affiliation(s)
- Hendrik Ballhausen
- Department of Radiation Oncology, University Hospital of LMU, Munich, Germany,
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