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Kakade NR, Kumar R, Sharma SD, Sapra BK. Dosimetry audit in advanced radiotherapy using in-house developed anthropomorphic head & neck phantom. Biomed Phys Eng Express 2024; 10:025022. [PMID: 38269653 DOI: 10.1088/2057-1976/ad222a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/24/2024] [Indexed: 01/26/2024]
Abstract
The treatment of head and neck (H&N) cancer presents formidable challenges due to the involvement of normal tissue and organs at risk (OARs) in the close vicinity. Ensuring the precise administration of the prescribed dose demands prior dose verification. Considering contour irregularity and heterogeneity in the H&N region, an anthropomorphic and heterogeneous H&N phantom was developed and fabricated locally for conducting the dosimetry audit in advanced radiotherapy treatments. This specialized phantom emulates human anatomy and incorporates a removable cylindrical insert housing a C-shaped planning target volume (PTV) alongside key OARs including the spinal cord, oral cavity, and bilateral parotid glands. Acrylonitrile Butadiene Styrene (ABS) was chosen for PTV and parotid fabrication, while Delrin was adopted for spinal cord fabrication. A pivotal feature of this phantom is the incorporation of thermoluminescent dosimeters (TLDs) within the PTV and OARs, enabling the measurement of delivered dose. To execute the dosimetry audit, the phantom, accompanied by dosimeters and comprehensive guidelines, was disseminated to multiple radiotherapy centers. Subsequently, hospital physicists acquired computed tomography (CT) scans to generate treatment plans for phantom irradiation. The treatment planning system (TPS) computed the anticipated dose distribution within the phantom, and post-irradiation TLD readings yielded actual dose measurements. The TPS calculated and TLD measured dose values at most of the locations inside the PTV were found comparable within ± 4%. The outcomes affirm the suitability of the developed anthropomorphic H&N phantom for precise dosimetry audits of advanced radiotherapy treatments.
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Affiliation(s)
- Nitin R Kakade
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India
| | - Rajesh Kumar
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India
| | - S D Sharma
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India
- Homi Bhabha National Institute, Mumbai-400094, India
| | - B K Sapra
- Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai-400094, India
- Homi Bhabha National Institute, Mumbai-400094, India
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2
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Stengl C, Panow K, Arbes E, Muñoz ID, Christensen JB, Neelsen C, Dinkel F, Weidner A, Runz A, Johnen W, Liermann J, Echner G, Vedelago J, Jäkel O. A phantom to simulate organ motion and its effect on dose distribution in carbon ion therapy for pancreatic cancer. Phys Med Biol 2023; 68:245013. [PMID: 37918022 DOI: 10.1088/1361-6560/ad0902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 11/02/2023] [Indexed: 11/04/2023]
Abstract
Objective. Carbon ion radiotherapy is a promising radiation technique for malignancies like pancreatic cancer. However, organs' motion imposes challenges for achieving homogeneous dose delivery. In this study, an anthropomorphicPancreasPhantom forIon-beamTherapy (PPIeT) was developed to simulate breathing and gastrointestinal motion during radiotherapy.Approach. The developed phantom contains a pancreas, two kidneys, a duodenum, a spine and a spinal cord. The shell of the organs was 3D printed and filled with agarose-based mixtures. Hounsfield Units (HU) of PPIeTs' organs were measured by CT. The pancreas motion amplitude in cranial-caudal (CC) direction was evaluated from patients' 4D CT data. Motions within the obtained range were simulated and analyzed in PPIeT using MRI. Additionally, GI motion was mimicked by changing the volume of the duodenum and quantified by MRI. A patient-like treatment plan was calculated for carbon ions, and the phantom was irradiated in a static and moving condition. Dose measurements in the organs were performed using an ionization chamber and dosimetric films.Main results. PPIeT presented tissue equivalent HU and reproducible breathing-induced CC displacements of the pancreas between (3.98 ± 0.36) mm and a maximum of (18.19 ± 0.44) mm. The observed maximum change in distance of (14.28 ± 0.12) mm between pancreas and duodenum was consistent with findings in patients. Carbon ion irradiation revealed homogenous coverage of the virtual tumor at the pancreas in static condition with a 1% deviation from the treatment plan. Instead, the dose delivery during motion with the maximum amplitude yielded an underdosage of 21% at the target and an increased uncertainty by two orders of magnitude.Significance. A dedicated phantom was designed and developed for breathing motion assessment of dose deposition during carbon ion radiotherapy. PPIeT is a unique tool for dose verification in the pancreas and its organs at risk during end-to-end tests.
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Affiliation(s)
- Christina Stengl
- Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 672, Heidelberg D-69120, Germany
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Kathrin Panow
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Eric Arbes
- Biomedical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Department for Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, Heidelberg D-69120, Germany
| | - Iván D Muñoz
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department for Physics and Astronomy, Heidelberg University, Im Neuenheimer Feld 226, Heidelberg D-69120, Germany
| | - Jeppe B Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institute (PSI), Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Christian Neelsen
- Department of Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Department of Nuclear Medicine, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, Berlin D-10117, Germany
| | - Fabian Dinkel
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Artur Weidner
- Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 672, Heidelberg D-69120, Germany
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Armin Runz
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Wibke Johnen
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Jakob Liermann
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Im Neuenheimer Feld 400, Heidelberg D-69120, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Im Neuenheimer Feld 450, Heidelberg D-69120, Germany
- National Center for Tumor Diseases (NCT), Im Neuenheimer Feld 460, D-69120 Heidelberg, Germany
| | - Gernot Echner
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - José Vedelago
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Im Neuenheimer Feld 400, Heidelberg D-69120, Germany
| | - Oliver Jäkel
- Division of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany
- Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital (UKHD), Im Neuenheimer Feld 450, Heidelberg D-69120, Germany
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Adachi T, Nakamura M, Iramina H, Matsumoto K, Ishihara Y, Tachibana H, Kurokawa S, Cho S, Tanaka K, Fukumoto K, Nishiyama T, Kito S, Mizowaki T. Identification of reproducible radiomic features from on-board volumetric images: A multi-institutional phantom study. Med Phys 2023; 50:5585-5596. [PMID: 36932977 DOI: 10.1002/mp.16376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND Radiomics analysis using on-board volumetric images has attracted research attention as a method for predicting prognosis during treatment; however, the lack of standardization is still one of the main concerns. PURPOSE This study investigated the factors that influence the reproducibility of radiomic features extracted from on-board volumetric images using an anthropomorphic radiomics phantom. Furthermore, a phantom experiment was conducted with different treatment machines from multiple institutions as external validation to identify reproducible radiomic features. METHODS The phantom was designed to be 35 × 20 × 20 cm with eight types of heterogeneous spheres (⌀ = 1, 2, and 3 cm). On-board volumetric images were acquired using 15 treatment machines from eight institutions. Of these, kilovoltage cone-beam computed tomography (kV-CBCT) image data acquired from four treatment machines at one institution were used as an internal evaluation dataset to explore the reproducibility of radiomic features. The remaining image data, including kV-CBCT, megavoltage-CBCT (MV-CBCT), and megavoltage computed tomography (MV-CT) provided by seven different institutions (11 treatment machines), were used as an external validation dataset. A total of 1,302 radiomic features, including 18 first-order, 75 texture, 465 (i.e., 93 × 5) Laplacian of Gaussian (LoG) filter-based, and 744 (i.e., 93 × 8) wavelet filter-based features, were extracted within the spheres. The intraclass correlation coefficient (ICC) was calculated to explore feature repeatability and reproducibility using an internal evaluation dataset. Subsequently, the coefficient of variation (COV) was calculated to validate the feature variability of external institutions. An absolute ICC exceeding 0.85 or COV under 5% was considered indicative of a highly reproducible feature. RESULTS For internal evaluation, ICC analysis showed that the median percentage of radiomic features with high repeatability was 95.2%. The ICC analysis indicated that the median percentages of highly reproducible features for inter-tube current, reconstruction algorithm, and treatment machine were decreased by 20.8%, 29.2%, and 33.3%, respectively. For external validation, the COV analysis showed that the median percentage of reproducible features was 31.5%. A total of 16 features, including nine LoG filter-based and seven wavelet filter-based features, were indicated as highly reproducible features. The gray-level run-length matrix (GLRLM) was classified as containing the most frequent features (N = 8), followed by the gray-level dependence matrix (N = 7) and gray-level co-occurrence matrix (N = 1) features. CONCLUSIONS We developed the standard phantom for radiomics analysis of kV-CBCT, MV-CBCT, and MV-CT images. With this phantom, we revealed that the differences in the treatment machine and image reconstruction algorithm reduce the reproducibility of radiomic features from on-board volumetric images. Specifically, the most reproducible features for external validation were LoG or wavelet filter-based GLRLM features. However, the acceptability of the identified features should be examined in advance at each institution before applying the findings to prognosis prediction.
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Affiliation(s)
- Takanori Adachi
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan
- Department of Advanced Medical Physics, Graduate School of Medicine, Kyoto University, Shogoin, Sakyo-ku, Kyoto, Japan
| | - Hiraku Iramina
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan
| | - Kazushige Matsumoto
- Department of Radiology, National Hospital Organization Kyoto Medical Center, Fushimi-ku, Kyoto, Japan
| | - Yoshitomo Ishihara
- Department of Radiation Oncology, Japanese Red Cross Wakayama Medical Center, Wakayama, Japan
| | - Hidenobu Tachibana
- Department of Radiation Oncology, National Cancer Center Hospital East, Kashiwa, Japan
| | - Shogo Kurokawa
- Department of Radiation Oncology, National Cancer Center Hospital East, Kashiwa, Japan
| | - SangYong Cho
- Division of Radiation Oncology, Chiba Cancer Center, Chuo-ku, Chiba, Japan
| | - Kazunori Tanaka
- Department of Radiation Oncology, Kyoto City Hospital, Nakagyo-ku, Kyoto, Japan
| | - Kenta Fukumoto
- Department of Radiation Oncology, Kyoto City Hospital, Nakagyo-ku, Kyoto, Japan
| | - Tomohiro Nishiyama
- Department of Radiation Oncology, Kyoto-Katsura Hospital, Nishikyo-ku, Kyoto, Japan
| | - Satoshi Kito
- Department of Radiotherapy, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Bunkyo-ku, Tokyo, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan
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Kunert P, Schlattl H, Trinkl S, Giussani A, Klein L, Janich M, Reichert D, Brix G. Reproduction of a conventional anthropomorphic female chest phantom by 3D-printing: Comparison of image contrasts and absorbed doses in CT. Med Phys 2023; 50:4734-4743. [PMID: 37415411 DOI: 10.1002/mp.16587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/10/2023] [Accepted: 06/11/2023] [Indexed: 07/08/2023] Open
Abstract
BACKGROUND The production of individualized anthropomorphic phantoms via three-dimensional (3D) printing methods offers promising possibilities to assess and optimize radiation exposures for specifically relevant patient groups (i.e., overweighed or pregnant persons) that are not adequately represented by standardized anthropomorphic phantoms. However, the equivalence of printed phantoms must be demonstrated exemplarily with respect to the resulting image contrasts and dose distributions. PURPOSE To reproduce a conventionally produced anthropomorphic phantom of a female chest and breasts and to evaluate their equivalence with respect to image contrasts and absorbed doses at the example of a computed tomography (CT) examination of the chest. METHODS In a first step, the effect of different print settings on the CT values of printed samples was systematically investigated. Subsequently, a transversal slice and breast add-ons of a conventionally produced female body phantom were reproduced using a multi-material extrusion-based printer, considering six different types of tissues (muscle, lung, adipose, and glandular breast tissue, as well as bone and cartilage). CT images of the printed and conventionally produced phantom parts were evaluated with respect to their geometric correspondence, image contrasts, and absorbed doses measured using thermoluminescent dosimeters. RESULTS CT values of printed objects are highly sensitive to the selected print settings. The soft tissues of the conventionally produced phantom could be reproduced with a good agreement. Minor differences in CT values were observed for bone and lung tissue, whereas absorbed doses to the relevant tissues were identical within the measurement uncertainties. CONCLUSION 3D-printed phantoms are with exception of minor contrast differences equivalent to their conventionally manufactured counterparts. When comparing the two production techniques, it is important to note that conventionally manufactured phantoms should not be considered as absolute benchmarks, as they also only approximate the human body in terms of its absorption, and attenuation of x-rays as well as its geometry.
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Affiliation(s)
- Patrizia Kunert
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Oberschleißheim, Germany
| | - Helmut Schlattl
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Oberschleißheim, Germany
| | - Sebastian Trinkl
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Oberschleißheim, Germany
| | - Augusto Giussani
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Oberschleißheim, Germany
| | - Lea Klein
- Department of Radiation Oncology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Martin Janich
- Department of Radiation Oncology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Detlef Reichert
- Department of Physics, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Gunnar Brix
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Oberschleißheim, Germany
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Breslin T, Paino J, Wegner M, Engels E, Fiedler S, Forrester H, Rennau H, Bustillo J, Cameron M, Häusermann D, Hall C, Krause D, Hildebrandt G, Lerch M, Schültke E. A Novel Anthropomorphic Phantom Composed of Tissue-Equivalent Materials for Use in Experimental Radiotherapy: Design, Dosimetry and Biological Pilot Study. Biomimetics (Basel) 2023; 8:230. [PMID: 37366825 DOI: 10.3390/biomimetics8020230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/26/2023] [Accepted: 05/28/2023] [Indexed: 06/28/2023] Open
Abstract
The production of anthropomorphic phantoms generated from tissue-equivalent materials is challenging but offers an excellent copy of the typical environment encountered in typical patients. High-quality dosimetry measurements and the correlation of the measured dose with the biological effects elicited by it are a prerequisite in preparation of clinical trials with novel radiotherapy approaches. We designed and produced a partial upper arm phantom from tissue-equivalent materials for use in experimental high-dose-rate radiotherapy. The phantom was compared to original patient data using density values and Hounsfield units obtained from CT scans. Dose simulations were conducted for broad-beam irradiation and microbeam radiotherapy (MRT) and compared to values measured in a synchrotron radiation experiment. Finally, we validated the phantom in a pilot experiment with human primary melanoma cells.
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Affiliation(s)
- Thomas Breslin
- Department of Oncology, Clinical Sciences, Lund University, 22185 Lund, Sweden
| | - Jason Paino
- Centre of Medical Radiation Physics, University of Wollongong, Wollongong 2522, Australia
| | - Marie Wegner
- Institute of Product Development and Mechanical Engineering Design, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Elette Engels
- Centre of Medical Radiation Physics, University of Wollongong, Wollongong 2522, Australia
- Australian Synchrotron/ANSTO, Clayton 3168, Australia
| | - Stefan Fiedler
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, 22607 Hamburg, Germany
| | - Helen Forrester
- School of Science, Royal Melbourne Institute of Technology (RMIT) University, Melbourne 3001, Australia
| | - Hannes Rennau
- Department of Radiooncology, Rostock University Medical Center, 18059 Rostock, Germany
| | - John Bustillo
- Centre of Medical Radiation Physics, University of Wollongong, Wollongong 2522, Australia
| | | | | | | | - Dieter Krause
- Institute of Product Development and Mechanical Engineering Design, Hamburg University of Technology, 21073 Hamburg, Germany
| | - Guido Hildebrandt
- Department of Radiooncology, Rostock University Medical Center, 18059 Rostock, Germany
| | - Michael Lerch
- Centre of Medical Radiation Physics, University of Wollongong, Wollongong 2522, Australia
| | - Elisabeth Schültke
- Department of Radiooncology, Rostock University Medical Center, 18059 Rostock, Germany
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Hurley L, Alashban Y, Albeshan S, England A, McEntee MF. The effect of breast shielding outside the field of view on breast entrance surface dose in axial X-ray examinations: a phantom study. Diagn Interv Radiol 2023; 29:555-560. [PMID: 37129301 PMCID: PMC10679606 DOI: 10.4274/dir.2023.232126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/03/2023] [Indexed: 05/03/2023]
Abstract
PURPOSE The purpose of this study was to evaluate the effect of outside-field-of-view (FOV) lead shielding on the entrance surface dose (ESD) of the breast on an anthropomorphic X-ray phantom for a variety of axial skeleton X-ray examinations. METHODS Using an anthropomorphic phantom and radiation dosimeter, the ESD of the breast was measured with and without outside-FOV shielding in anterior-posterior (AP) abdomen, AP cervical spine, occipitomental 30° (OM30) facial bones, AP lumbar spine, and lateral lumbar spine radiography. The effect of several exposure parameters, including a low milliampere-seconds technique, grid use, automatic exposure control use, wraparound lead (WAL) use, trolley use, and X-ray table use, on the ESD of the breast with and without outside-FOV shielding was investigated. The mean ESD (μSv) and standard deviation for each radiographic protocol were calculated. A one-tailed Student's t-test was carried out to evaluate whether ESD to the breast was reduced with the use of outside-FOV shielding. RESULTS A total of 920 breast ESD measurements were recorded across the different protocol parameters. The largest decrease in mean ESD of the breast with outside-FOV shielding was 0.002 μSv (P = 0.084), recorded in the AP abdomen on the table with a grid, OM30 on the table with a grid, OM30 standard protocol on the trolley, and OM30 on the trolley with WAL protocols. This decrease was found to be statistically non-significant. CONCLUSION This study found no significant decrease in the ESD of the breast with the use of outside-FOV shielding for the AP abdomen, AP cervical spine, OM30 facial bones, AP lumbar spine, or lateral lumbar spine radiography across a range of protocols.
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Affiliation(s)
- Lauren Hurley
- Department of Medical Imaging and Radiation Therapy, University College Cork, School of Medicine, Brookfield Health Sciences, Munster, Ireland
| | - Yazeed Alashban
- Department of Radiological Sciences, King Saud University, College of Applied Medical Sciences, Riyadh, Saudi Arabia
| | - Salman Albeshan
- Department of Radiological Sciences, King Saud University, College of Applied Medical Sciences, Riyadh, Saudi Arabia
| | - Andrew England
- Department of Medical Imaging and Radiation Therapy, University College Cork, School of Medicine, Brookfield Health Sciences, Munster, Ireland
| | - Mark F. McEntee
- Department of Medical Imaging and Radiation Therapy, University College Cork, School of Medicine, Brookfield Health Sciences, Munster, Ireland
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7
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Peppa V, Thomson RM, Enger SA, Fonseca GP, Lee C, Lucero JNE, Mourtada F, Siebert FA, Vijande J, Papagiannis P. A MC-based anthropomorphic test case for commissioning model-based dose calculation in interstitial breast 192-Ir HDR brachytherapy. Med Phys 2023. [PMID: 37194638 DOI: 10.1002/mp.16455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/08/2023] [Accepted: 04/20/2023] [Indexed: 05/18/2023] Open
Abstract
PURPOSE To provide the first clinical test case for commissioning of 192 Ir brachytherapy model-based dose calculation algorithms (MBDCAs) according to the AAPM TG-186 report workflow. ACQUISITION AND VALIDATION METHODS A computational patient phantom model was generated from a clinical multi-catheter 192 Ir HDR breast brachytherapy case. Regions of interest (ROIs) were contoured and digitized on the patient CT images and the model was written to a series of DICOM CT images using MATLAB. The model was imported into two commercial treatment planning systems (TPSs) currently incorporating an MBDCA. Identical treatment plans were prepared using a generic 192 Ir HDR source and the TG-43-based algorithm of each TPS. This was followed by dose to medium in medium calculations using the MBDCA option of each TPS. Monte Carlo (MC) simulation was performed in the model using three different codes and information parsed from the treatment plan exported in DICOM radiation therapy (RT) format. Results were found to agree within statistical uncertainty and the dataset with the lowest uncertainty was assigned as the reference MC dose distribution. DATA FORMAT AND USAGE NOTES The dataset is available online at http://irochouston.mdanderson.org/rpc/BrachySeeds/BrachySeeds/index.html,https://doi.org/10.52519/00005. Files include the treatment plan for each TPS in DICOM RT format, reference MC dose data in RT Dose format, as well as a guide for database users and all files necessary to repeat the MC simulations. POTENTIAL APPLICATIONS The dataset facilitates the commissioning of brachytherapy MBDCAs using TPS embedded tools and establishes a methodology for the development of future clinical test cases. It is also useful to non-MBDCA adopters for intercomparing MBDCAs and exploring their benefits and limitations, as well as to brachytherapy researchers in need of a dosimetric and/or a DICOM RT information parsing benchmark. Limitations include specificity in terms of radionuclide, source model, clinical scenario, and MBDCA version used for its preparation.
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Affiliation(s)
- Vasiliki Peppa
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Radiotherapy Department, General Hospital of Athens Alexandra, Athens, Greece
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada
| | - Shirin A Enger
- Medical Physics Unit, Department of Oncology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Gabriel P Fonseca
- Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Maastricht, Netherlands
| | - Choonik Lee
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph N E Lucero
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada
| | - Firas Mourtada
- Department of Radiation Oncology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Frank-André Siebert
- UK S-H, Campus Kiel, Klinik für Strahlentherapie (Radioonkologie), Kiel, Germany
| | - Javier Vijande
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe)-Universitat de Valencia (UV), Instituto de Física Corpuscular, IFIC (UV-CSIC), Burjassot, Spain
| | - Panagiotis Papagiannis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Ikejimba L, Farooqui A, Ghazi P. Hyperia: A novel methodology of developing anthropomorphic breast phantoms for X-ray imaging modalities - Part I: Concept and initial findings. Med Phys 2023; 50:702-718. [PMID: 36273400 PMCID: PMC9931645 DOI: 10.1002/mp.16045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/06/2022] [Accepted: 10/04/2022] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To introduce a novel methodology for developing anthropomorphic breast phantoms for use in X-ray-based imaging modalities. METHODS "Hyperization" is a quasi-stippling mapping operation in which regions of varying grayscale values in a 2D image are transformed into regions of varying holes on a surface. The holes can be cut or engraved on the sheet of paper using a high-resolution laser cutter/engraver. In hyperization, the main parameters are the size and the distance between the holes. Here, we introduce the concept and chronicle the development and characterization of a proof-of-concept prototype. In this study, we hypothesized that a resulting "Hyperia" phantom would be a realistic representative of a patient's breast tissue: it would exhibit similar X-ray properties and show textural complexities. We used breast computed tomography (bCT) images of real patients as the input models. Using a previously developed segmentation method, the input CT images were segmented into different tissue classes (skin, adipose, and fibroglandular). The segmented images were then "Hyperized". A series of Monte Carlo simulations were conducted to find the optimal hyperization parameters. Different laser cutter/engraver systems and substrate materials were explored to find a viable option for developing an entire Hyperia breast phantom. The resulting phantom was imaged on a prototype breast CT system, and the resulting images were evaluated based on physical properties and similarity to the original patient data. RESULTS The simulation results indicate close similarities - both in the distribution of different tissue types and the resulting CT numbers - between the patient bCT image and the bCT of the Hyperia phantom, regardless of the breast size and density: the Pearson correlation coefficient (ρ) ranged from 0.88 in a BIRADS A breast to 0.94 in BIRADS C and D breasts (ρ of 1.00 suggests perfect structural similarity), and the volumetric mean squared error ranged from 0.0033 (in BIRADS D breast) to 0.0059 (in BIRADS A), suggesting good agreement between the resulting CT numbers. For fabricating the slices, the office paper was found to be an optimal substrate material, with the Hyperization parameters of (α, β) = (0.200 mm, 0.400 mm). CONCLUSION A novel phantom can be used for X-ray-based breast cancer imaging systems. The main advantage is that only one material is used for creating a contrast between different tissue types in an image.
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Stokkeland PJ, Andersen E, Bjørndal MM, Moen AI, Aslaksen S, Grasaas-Albrecht CP, Hyldmo PK. Maintaining immobilization devices on trauma patients during chest and pelvic X-ray: a feasibility study. Acta Radiol 2022; 63:692-697. [PMID: 33906416 DOI: 10.1177/02841851211008386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Most trauma systems and traumatic spinal injury guidelines mandate spinal stabilization from the site of injury to a radiological confirmation or refutal of spinal injury. Vacuum mattresses have been advocated for patients in need of prehospital spinal stabilization. PURPOSE To investigate the effect of different vacuum mattresses on standard resuscitation bay conventional radiography of chest and pelvis, especially regarding artefacts. MATERIAL AND METHODS We used a mobile X-ray machine to perform chest and pelvic conventional radiography on an anthropomorphic whole-body phantom with a trauma transfer board, three different vacuum mattresses, and without any stabilization device. The vacuum mattresses were investigated in activated, deactivated, and stretched after deactivated states. Two radiologists assessed the artefacts independently. Agreement was measured using kappa coefficient. RESULTS All radiographs were of good technical quality and fully diagnostic. With the exception of one disagreed occurrence, artefacts were seen to hamper clinical judgment exclusively with activated vacuum mattresses. There was substantial agreement on artefact assessment. The observed agreement was 0.82 with a kappa coefficient of 0.71. The first vacuum mattress caused no artefacts hampering with clinical judgment. CONCLUSION Our study concludes that it is feasible to maintain some vacuum mattresses through resuscitation bay conventional radiography of chest and pelvis. They do not result in artefacts hampering with clinical judgment. Our vacuum mattress No. 1 is recommendable for this purpose. Together with our previous findings our present results indicate that some vacuum mattresses may be used throughout the initial resuscitation bay assessment and CT examination.
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Affiliation(s)
| | - Erlend Andersen
- Clinic for Medical Services, Sørlandet Hospital Kristiansand, Kristiansand, Norway
| | | | - Anita Imeland Moen
- Department of Radiology, Sørlandet Hospital Kristiansand, Kristiansand, Norway
| | | | | | - Per Kristian Hyldmo
- Trauma Unit, Sørlandet Hospital, Kristiansand, Norway
- Faculty of Health Sciences, University of Stavanger, Stavanger, Norway
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Yen TY, Chuang KC, Fu HM, Feng CJ, Lien KY, Hsu SM. Estimation of the Surface Dose in Breast Irradiation by the Beam Incident Angle and the 1 cm Depth Dose. J Clin Med 2022; 11:2154. [PMID: 35456253 DOI: 10.3390/jcm11082154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/31/2022] [Accepted: 04/06/2022] [Indexed: 11/30/2022] Open
Abstract
To develop a method of estimating surface dose in whole breast irradiation, we used an anthropomorphic phantom with accessories for the simulation of different breast sizes. The surface points, which are measured by TLDs, are set along with two main directions, superior-inferior and medial-lateral. The incident angle between the photon beam and the surface and the doses at 1 cm beneath the surface at every point are assessed by a computerized treatment planning system (cTPS). With the prescription dose of 200 cGy, the average surface doses under tangential irradiation are 97.73 (±14.96) cGy, 99.90 (±10.73) cGy, and 105.26 (±9.21) cGy for large, medium, and small breast volumes, respectively. The surface dose increased in the model of small breast volume without significance (p = 0.39). The linear analysis between surface dose and the incident angle is y = 0.5258x + 69.648, R2 = 0.7131 (x: incident angle and y: surface dose). We develop the percentage of skin surface dose with reference to a depth of 1 cm (PSDR1cm) to normalize the inhomogeneous dose. The relationship between incident angle and PSDR1cm is y = 0.1894x + 36.021, R2 = 0.6536 (x: incident angle and y: PSDR1cm) by linear analysis. In conclusion, the surface dose in whole breast irradiation could be estimated from this linear relationship between PSDR1cm and incident angle in daily clinical practice by cTPS. Further in vivo data should be studied to verify this formula.
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11
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Majer M, Ambrožová I, Davídková M, De Saint-Hubert M, Kasabašić M, Knežević Ž, Kopeć R, Krzempek D, Krzempek K, Miljanić S, Mojżeszek N, Veršić I, Stolarczyk L, Harrison RM, Olko P. Out-of-field doses in pediatric craniospinal irradiations with 3D-CRT, VMAT and scanning proton radiotherapy - a phantom study. Med Phys 2022; 49:2672-2683. [PMID: 35090187 DOI: 10.1002/mp.15493] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 12/01/2021] [Accepted: 01/12/2022] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Craniospinal irradiation (CSI) has greatly increased survival rates for patients with a diagnosis of medulloblastoma and other primitive neuroectodermal tumors. However, as it includes exposure of a large volume of healthy tissue to unwanted doses, there is a strong concern about the complications of the treatment, especially for the children. To estimate the risk of second cancers and other unwanted effects, out-of-field dose assessment is necessary. The purpose of this study is to evaluate and compare out-of-field doses in pediatric CSI treatment using conventional and advanced photon radiotherapy (RT) and advanced proton therapy. To our knowledge, it is the first such comparison based on in-phantom measurements. Additionally, for out-of-field doses during photon RT in this and other studies, comparisons were made using analytical modeling. METHODS In order to describe the out-of-field doses absorbed in a pediatric patient during actual clinical treatment, an anthropomorphic phantom which mimics the 10-year-old child was used. Photon 3D-conformal radiotherapy (3D-CRT) and two advanced, highly conformal techniques: photon volumetric modulated arc therapy (VMAT) and active pencil beam scanning (PBS) proton radiotherapy were used for CSI treatment. Radiophotoluminescent (RPL) and poly-allyl-diglycol-carbonate (PADC) nuclear track detectors were used for photon and neutron dosimetry in the phantom, respectively. Out-of-field doses from neutrons were expressed in terms of dose equivalent. A two-Gaussian model was implemented for out-of-field doses during photon RT. RESULTS The mean VMAT photon doses per target dose to all organs in this study were under 50% of the target dose (i.e., <500 mGy/Gy), while the mean 3D-CRT photon dose to oesophagus, gall bladder and thyroid, exceeded that value. However, for 3D-CRT, better sparing was achieved for eyes and lungs. The mean PBS photon doses for all organs were up to 3 orders of magnitude lower compared to VMAT and 3D-CRT and exceeded 10 mGy/Gy only for the oesophagus, intestine and lungs. The mean neutron dose equivalent during PBS for 8 organs of interest (thyroid, breasts, lungs, liver, stomach, gall bladder, bladder, prostate) ranged from 1.2 mSv/Gy for bladder to 23.1 mSv/Gy for breasts. Comparison of out-of-field doses in this and other phantom studies found in the literature showed that a simple and fast two-Gaussian model for out-of-field doses as a function of distance from the field edge can be applied in a CSI using photon RT techniques. CONCLUSIONS PBS is the most promising technique for out-of-field dose reduction in comparison to photon techniques. Among photon techniques, VMAT is a preferred choice for most of out-of-field organs and especially for the thyroid, while doses for eyes, breasts and lungs, are lower for 3D-CRT. For organs outside the field edge, a simple analytical model can be helpful for clinicians involved in treatment planning using photon RT but also for retrospective data analysis for cancer risk estimates and epidemiology in general. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Marija Majer
- Ruđer Bošković Institute, Zagreb, 10000, Croatia
| | - Iva Ambrožová
- Nuclear Physics Institute of the CAS, Řež, CZ-250 68, Czech Republic
| | - Marie Davídková
- Nuclear Physics Institute of the CAS, Řež, CZ-250 68, Czech Republic
| | | | - Mladen Kasabašić
- Osijek University Hospital, Osijek, 31000, Croatia.,Faculty of Medicine Osijek, J.J. Strossmayer University of Osijek, Osijek, 31000, Croatia
| | | | - Renata Kopeć
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland
| | - Dawid Krzempek
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland
| | - Katarzyna Krzempek
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland
| | | | - Natalia Mojżeszek
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland
| | - Ivan Veršić
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb, 10000, Croatia
| | - Liliana Stolarczyk
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland.,Danish Center for Particle Therapy, Aarhus, Denmark
| | - Roger M Harrison
- University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Paweł Olko
- Institute of Nuclear Physics Polish Academy of Sciences, Krakow, 31-342, Poland
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12
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Anton M, Reginatto M, Elster C, Mäder U, Schopphoven S, Sechopoulos I, van Engen R. The regression detectability index RDI for mammography images of breast phantoms with calcification-like objects and anatomical background. Phys Med Biol 2021; 66. [PMID: 34706354 DOI: 10.1088/1361-6560/ac33ea] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/27/2021] [Indexed: 11/11/2022]
Abstract
Currently, quality assurance measurements in mammography are performed on unprocessed images. For diagnosis, however, radiologists are provided with processed images. This image processing is optimised for images of human anatomy and therefore does not always perform satisfactorily with technical phantoms. To overcome this problem, it may be possible to use anthropomorphic phantoms reflecting the anatomic structure of the human breast in place of technical phantoms when carrying out task-specific quality assessment using model observers. However, the use of model observers is hampered by the fact that a large number of images needs to be acquired. A recently published novel observer called the regression detectability index (RDI) needs significantly fewer images, but requires the background of the images to be flat. Therefore, to be able to apply the RDI to images of anthropomorphic phantoms, the anatomic background needs to be removed. For this, a procedure in which the anatomical structures are fitted by thin plate spline (TPS) interpolation has been developed. When the object to be detected is small, such as a calcification-like lesion, it is shown that the anatomic background can be removed successfully by subtracting the TPS interpolation, which makes the background-free image accessible to the RDI. We have compared the detectability obtained by the RDI with TPS background subtraction to results of the channelized Hotelling observer (CHO) and human observers. With the RDI, results for the detectabilityd'can be obtained using 75% fewer images compared to the CHO, while the same uncertainty ofd'is achieved. Furthermore, the correlation ofd'(RDI) with the results of human observers is at least as good as that ofd'(CHO) with human observers.
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Affiliation(s)
- M Anton
- Physikalisch-Technische Bundesanstalt Braunschweig and Berlin, Germany
| | - M Reginatto
- Physikalisch-Technische Bundesanstalt Braunschweig and Berlin, Germany
| | - C Elster
- Physikalisch-Technische Bundesanstalt Braunschweig and Berlin, Germany
| | - U Mäder
- Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen, Germany
| | - S Schopphoven
- Reference Centre for Mammography Screening Southwest Germany, Marburg, Germany
| | - I Sechopoulos
- Radboud University Medical Center, Nijmegen, The Netherlands.,LRCB Dutch Expert Centre for Screening, Nijmegen, The Netherlands
| | - R van Engen
- LRCB Dutch Expert Centre for Screening, Nijmegen, The Netherlands
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Halloran A, Newhauser W, Chu C, Donahue W. Personalized 3D-printed anthropomorphic phantoms for dosimetry in charged particle fields. Phys Med Biol 2021; 66. [PMID: 34654002 DOI: 10.1088/1361-6560/ac3047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/15/2021] [Indexed: 11/11/2022]
Abstract
Anthropomorphic phantoms used for radiation dose measurements are designed to mimic human tissue in shape, size, and tissue composition. Reference phantoms are widely available and are sufficiently similar to many, but not all, human subjects. 3D printing has the potential to overcome some of these shortcomings by enabling rapid fabrication of personalized phantoms for individual human subjects based on radiographic imaging data.Objective. The objective of this study was to test the efficacy of personalized 3D printed phantoms for charged particle therapy. To accomplish this, we measured dose distributions from 6 to 20 MeV electron beams, incident on printed and molded slices of phantoms.Approach. Specifically, we determined the radiological properties of 3D printed phantoms, including beam penetration range. Additionally, we designed and printed a personalized head phantom to compare results obtained with a commercial, reference head phantom for quality assurance of therapeutic electron beam dose calculations.Main Results. For regions of soft tissue, gamma index analyses revealed a 3D printed slice was able to adequately model the same electron beam penetration ranges as the molded reference slice. The printed, personalized phantom provided superior dosimetric accuracy compared to the molded reference phantom for electron beam dose calculations at all electron beam energies. However, current limitations in the ability to print high-density structures, such as bone, limited pass rates of 60% or better at 16 and 20 MeV electron beam energies.Significance. This study showed that creating personalized phantoms using 3D printing techniques is a feasible way to substantially improve the accuracy of dose measurements of therapeutic electron beams, but further improvements in printing techniques are necessary in order to increase the printable density in phantoms.
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Affiliation(s)
- Andrew Halloran
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Wayne Newhauser
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, United States of America.,Department of Radiation Physics, Mary Bird Perkins Cancer Center, Baton Rouge, Louisiana, United States of America
| | - Connel Chu
- Department of Radiation Physics, Mary Bird Perkins Cancer Center, Baton Rouge, Louisiana, United States of America
| | - William Donahue
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, United States of America
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Acciavatti RJ, Cohen EA, Maghsoudi OH, Gastounioti A, Pantalone L, Hsieh MK, Conant EF, Scott CG, Winham SJ, Kerlikowske K, Vachon C, Maidment ADA, Kontos D. Incorporating Robustness to Imaging Physics into Radiomic Feature Selection for Breast Cancer Risk Estimation. Cancers (Basel) 2021; 13:5497. [PMID: 34771660 PMCID: PMC8582675 DOI: 10.3390/cancers13215497] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/16/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Digital mammography has seen an explosion in the number of radiomic features used for risk-assessment modeling. However, having more features is not necessarily beneficial, as some features may be overly sensitive to imaging physics (contrast, noise, and image sharpness). To measure the effects of imaging physics, we analyzed the feature variation across imaging acquisition settings (kV, mAs) using an anthropomorphic phantom. We also analyzed the intra-woman variation (IWV), a measure of how much a feature varies between breasts with similar parenchymal patterns-a woman's left and right breasts. From 341 features, we identified "robust" features that minimized the effects of imaging physics and IWV. We also investigated whether robust features offered better case-control classification in an independent data set of 575 images, all with an overall BI-RADS® assessment of 1 (negative) or 2 (benign); 115 images (cases) were of women who developed cancer at least one year after that screening image, matched to 460 controls. We modeled cancer occurrence via logistic regression, using cross-validated area under the receiver-operating-characteristic curve (AUC) to measure model performance. Models using features from the most-robust quartile of features yielded an AUC = 0.59, versus 0.54 for the least-robust, with p < 0.005 for the difference among the quartiles.
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Affiliation(s)
- Raymond J. Acciavatti
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Eric A. Cohen
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Omid Haji Maghsoudi
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Aimilia Gastounioti
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Lauren Pantalone
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Meng-Kang Hsieh
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Emily F. Conant
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Christopher G. Scott
- Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA; (C.G.S.); (S.J.W.); (C.V.)
| | - Stacey J. Winham
- Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA; (C.G.S.); (S.J.W.); (C.V.)
| | - Karla Kerlikowske
- Departments of Medicine and Epidemiology/Biostatistics, Women’s Health Clinical Research Center, UCSF, San Francisco, CA 94143, USA;
| | - Celine Vachon
- Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, MN 55905, USA; (C.G.S.); (S.J.W.); (C.V.)
| | - Andrew D. A. Maidment
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
| | - Despina Kontos
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.A.C.); (O.H.M.); (A.G.); (L.P.); (M.-K.H.); (E.F.C.); (A.D.A.M.); (D.K.)
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15
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Arimoto A, Asada Y. Investigation of backscatter factor in medical radiography using anthropomorphic phantom by optically stimulated luminescence dosimeter. Biomed Phys Eng Express 2021; 7. [PMID: 34438389 DOI: 10.1088/2057-1976/ac21ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/26/2021] [Indexed: 11/11/2022]
Abstract
At the diagnostic reference level (DRL) related to medical radiation, DRL quantity for general radiography is the entrance surface dose (ESD). Calculation of the ESD in medical radiography requires the backscatter factor (BSF), but derivation of the BSF requires assessment of an irradiated simulation of a human body. The present study used optically stimulated luminescence (OSL) dosimeters and an anthropomorphic phantom as the irradiated body, and the BSF was calculated for different half value layer (HVL)s and field sizes. The need for different BSFs for different regions was also investigated by derivationing of the BSFs for different regions. The pelvis of a RANDO phantom was irradiated under the conditions of the HVL of 2.0, 3.1, and 4.6 mmAl; tube current of 200 mA; irradiation time of 0.1 s; source surface distance of 100 cm; and field sizes of 10 × 10 cm2, 20 cm2, 30 cm2, and 40 cm2. Measurement in air was performed under the same conditions. Several threads were stretched through the air with tissue paper placed on them and the nanoDot dosimeters placed on the paper. Four dosimeters were placed, and measurement was performed 5 times under each set of conditions. The compared radiographed regions were the skull, chest, and pelvis. The BSF increased with increasing HVL size and with increasing field size. The larger the HVL, the larger the difference between field sizes of 10 × 10 cm2and 40 × 40 cm2and the larger the increase in BSF relative to the increase in field size. The BSF differed by region, from large to small in the order chest, pelvis, and skull. The results thus showed that the BSF differs by the radiographed region. Thus, it is desirable to determine the BSF in each radiographed region by investigation with an anthropomorphic phantom.
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Affiliation(s)
- Akihiro Arimoto
- Hamamatsu Medical Center Department of Radiological Technology, Japan
| | - Yasuki Asada
- Fujita Health University School of Medical Sciences Faculty of Radiological Technology, Japan
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Marot M, Elter A, Mann P, Schwahofer A, Lang C, Johnen W, Körber SA, Beuthien-Baumann B, Gillmann C. Technical Note: On the feasibility of performing dosimetry in target and organ at risk using polymer dosimetry gel and thermoluminescence detectors in an anthropomorphic, deformable, and multimodal pelvis phantom. Med Phys 2021; 48:5501-5510. [PMID: 34260079 DOI: 10.1002/mp.15096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/28/2021] [Accepted: 06/25/2021] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE To assess the feasibility of performing dose measurements in the target (prostate) and an adjacent organ at risk (rectum) using polymer dosimetry gel and thermoluminescence detectors (TLDs) in an anthropomorphic, deformable, and multimodal pelvis phantom (ADAM PETer). METHODS The 3D printed prostate organ surrogate of the ADAM PETer phantom was filled with polymer dosimetry gel. Nine TLD600 (LiF:Mg,Ti) were installed in 3 × 3 rows on a specifically designed 3D-printed TLD holder. The TLD holder was inserted into the rectum at the level of the prostate and fixed by a partially inflated endorectal balloon. Computed tomography (CT) images were taken and treatment planning was performed. A prescribed dose of 4.5 Gy was delivered to the planning target volume (PTV). The doses measured by the dosimetry gel in the prostate and the TLDs in the rectum ("measured dose") were compared to the doses calculated by the treatment planning system ("planned dose") on a voxel-by-voxel basis. RESULTS In the prostate organ surrogate, the 3D-γ-index was 97.7% for the 3% dose difference and 3 mm distance to agreement criterium. In the center of the prostate organ surrogate, measured and planned doses showed only minor deviations (<0.1 Gy, corresponding to a percentage error of 2.22%). On the edges of the prostate, slight differences between planned and measured doses were detected with a maximum deviation of 0.24 Gy, corresponding to 5.3% of the prescribed dose. The difference between planned and measured doses in the TLDs was on average 0.08 Gy (range: 0.02-0.21 Gy), corresponding to 1.78% of the prescribed dose (range: 0.44%-4.67%). CONCLUSIONS The present study demonstrates the feasibility of using polymer dosimetry gel and TLDs for 3D and 1D dose measurements in the prostate and the rectum organ surrogates in an anthropomorphic, deformable and multimodal phantom. The described methodology might offer new perspectives for end-to-end tests in image-guided adaptive radiotherapy workflows.
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Affiliation(s)
- Mathieu Marot
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Alina Elter
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Philipp Mann
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany.,HQ-Imaging GmbH, Heidelberg, Germany
| | - Andrea Schwahofer
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Clemens Lang
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Wibke Johnen
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany
| | - Stefan A Körber
- Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Bettina Beuthien-Baumann
- Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Clarissa Gillmann
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation Research in Oncology (NCRO), Heidelberg, Germany.,National Center for Tumor Diseases (NCT), Heidelberg, Germany
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Cruz-Bastida JP, Marshall EL, Reiser N, George J, Pearson EA, Feinstein KA, Al-Hallaq HA, Burton CS, Beaulieu D, MacDougall RD, Reiser I. Development of a neonate X-ray phantom for 2D imaging applications using single-tone inkjet printing. Med Phys 2021; 48:4944-4954. [PMID: 34255871 DOI: 10.1002/mp.15086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 04/16/2021] [Accepted: 06/17/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Inkjet printers can be used to fabricate anthropomorphic phantoms by the use of iodine-doped ink. However, challenges persist in implementing this technique. The calibration from grayscale to ink density is complex and time-consuming. The purpose of this work is to develop a printing methodology that requires a simpler calibration and is less dependent on printer characteristics to produce the desired range of x-ray attenuation values. METHODS Conventional grayscale printing was substituted by single-tone printing; that is, the superposition of pure black layers of iodinated ink. Printing was performed with a consumer-grade inkjet printer using ink made of potassium-iodide (KI) dissolved in water at 1 g/ml. A calibration for the attenuation of ink was measured using a commercial x-ray system at 70 kVp. A neonate radiograph obtained at 70 kVp served as an anatomical model. The attenuation map of the neonate radiograph was processed into a series of single-tone images. Single-tone images were printed, stacked, and imaged at 70 kVp. The phantom was evaluated by comparing attenuation values between the printed phantom and the original radiograph; attenuation maps were compared using the structural similarity index measure (SSIM), while attenuation histograms were compared using the Kullback-Leibler (KL) divergence. A region of interest (ROI)-based analysis was also performed, where the attenuation distribution within given ROIs was compared between phantom and patient. The phantom sharpness was evaluated in terms of modulation transfer function (MTF) estimates and signal spread profiles of high spatial resolution features in the image. RESULTS The printed phantom required 36 pages. The printing queue was automated and it took about 2 h to print the phantom. The radiograph of the printed phantom demonstrated a close resemblance to the original neonate radiograph. The SSIM of the phantom with respect to that of the patient was 0.53. Both patient and phantom attenuation histograms followed similar distributions, and the KL divergence between such histograms was 0.20. The ROI-based analysis showed that the largest deviations from patient attenuation values were observed at the higher and lower ends of the attenuation range. The limiting resolution of the proposed methodology was about 1 mm. CONCLUSION A methodology to generate a neonate phantom for 2D imaging applications, using single-tone printing, was developed. This method only requires a single-value calibration and required less than 2 h to print a complete phantom.
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Affiliation(s)
| | - Emily L Marshall
- Department of Radiology, University of Chicago, Chicago, IL, 60637, USA
| | - Nikolaj Reiser
- Department of Radiology, University of Chicago, Chicago, IL, 60637, USA
| | - Jonathan George
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 60637, USA
| | - Erik A Pearson
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 60637, USA
| | - Kate A Feinstein
- Department of Radiology, University of Chicago, Chicago, IL, 60637, USA
| | - Hania A Al-Hallaq
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 60637, USA
| | - Christiane S Burton
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Danielle Beaulieu
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Robert D MacDougall
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ingrid Reiser
- Department of Radiology, University of Chicago, Chicago, IL, 60637, USA
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18
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Black DG, Yazdi YO, Wong J, Fedrigo R, Uribe C, Kadrmas DJ, Rahmim A, Klyuzhin IS. Design of an anthropomorphic PET phantom with elastic lungs and respiration modeling. Med Phys 2021; 48:4205-4217. [PMID: 34031896 DOI: 10.1002/mp.14998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Respiratory motion during positron emission tomography (PET) scans can be a major detriment to image quality in oncological imaging. The impact of motion on lesion quantification and detectability can be assessed using phantoms with realistic anatomy representation and motion modeling. In this work, we develop an anthropomorphic phantom for PET imaging that combines anatomic fidelity and a realistic breathing mechanism with deformable lungs. METHODS We start from a previously developed anatomically accurate but static phantom of a human torso, and add elastic lungs with a highly controllable actuation mechanism which replicates the physics of breathing. The space outside the lungs is filled with a radioactive water solution. To maintain anatomical accuracy and realistic gamma ray attenuation in the torso, all motion mechanisms and actuators are positioned outside of the phantom compartment. The actuation mechanism can produce custom respiratory waveforms with breathing rates up to 25 breaths per minute and tidal volumes up to 1200 mL. RESULTS Several tests were performed to validate the performance of the phantom assembly, in which the phantom was filled with water and given respiratory waveforms to execute. All parts demonstrated expected performance. Force requirements were not exceeded and no leaks were detected, although continued use of the phantom is required to evaluate wear. The motion of the lungs was determined to be within a reasonable realistic range. CONCLUSIONS The full mechanical design is described in this paper, as well as a software application with graphical user interface which was developed to plan and visualize respiratory patterns. Both are available online as open source files. The developed phantom will facilitate future work in evaluating the impact of respiratory motion on lesion quantification and detectability in clinical practice.
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Affiliation(s)
- David G Black
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Yas Oloumi Yazdi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Jeremy Wong
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Roberto Fedrigo
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,BC Cancer Research Institute, Vancouver, BC, Canada
| | - Carlos Uribe
- Department of Functional Imaging, BC Cancer, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Dan J Kadrmas
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Arman Rahmim
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,BC Cancer Research Institute, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Ivan S Klyuzhin
- BC Cancer Research Institute, Vancouver, BC, Canada.,Department of Radiology, University of British Columbia, Vancouver, BC, Canada
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19
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Zhang Y, Yan S, Cui Z, Wang Y, Li Z, Yin Y, Li B, Quan H, Zhu J. Out-of-field dose assessment for a 1.5 T MR-Linac with optically stimulated luminescence dosimeters. Med Phys 2021; 48:4027-4037. [PMID: 33714229 PMCID: PMC8360091 DOI: 10.1002/mp.14839] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/04/2021] [Accepted: 03/04/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To assess the out-of-field surface and internal dose of the 1.5 T MR-Linac compared to the conventional external beam linac using optically stimulated luminescence dosimeters (OSLDs), and evaluate the out-of-field dose calculation accuracy of the Monaco treatment planning system (TPS) of the 1.5T MR-Linac. METHODS A cubic solid water phantom, with OSLDs on the surface, was vertically irradiated by MR-Linac square fields with different sizes. In addition, OSLDs were arranged out of the beam edges in four directions. An anthropomorphic adult phantom, with 125 cm3 simulated volume, was irradiated in four orthogonal directions by both MR-Linac and conventional linac at the head, thoracic, and pelvic sites. Out-of-field doses were measured by OSLDs on both the surface and internal emulational organs at risk (OARs). The results were compared to the simulated dose from Monaco TPS. RESULTS At different field sizes (5 × 5 to 20 × 20 cm2 ) and distances (1 to 10 cm) to beam edge, the out-of-field surface dose measured on MR-Linac varied from 0.16 % (10 cm to 5 × 5 cm2 edge) to 7.02 % (1 cm to 20 × 20 cm2 edge) of the maximum dose laterally and from 0.14 % (10 cm to 5 × 5 cm2 edge) to 8.56 % (1 cm to 20 × 20 cm2 edge) of the maximum dose longitudinally. Compared to the OSLDs measured data, the Monaco TPS presented an overestimate of the out-of-field dose of OARs at 0-2 % isodose area on both surface and internal check points, and the overestimation gets greater as the distance increases. The underestimation was found to be 0-35% at 2-5% isodose area on both surface and internal check points. Compared to the conventional linac, MR-Linac delivered higher average values of out-of-field dose on surface check points (20%, 19%, 21%) and internal simulated OARs (42%, 37%, 9%) of the anthropomorphic phantom at head, thoracic, and pelvic irradiations, respectively. CONCLUSIONS Compared to the conventional linac, MR-Linac has the same out-of-field dose distribution. However, considering the absolute dose values, MR-Linac delivered relatively higher out-of-field doses on both surface and internal OARs. Additional radiation shielding to patients undergoing MR-Linac may provide protection from out-of-field exposure.
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Affiliation(s)
- Yan Zhang
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China.,Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Shaojie Yan
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,School of Nuclear Science and Technology, University of South China, Hengyang, P.R. China
| | - Zhen Cui
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yungang Wang
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Zhenjiang Li
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Yong Yin
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Baosheng Li
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China
| | - Hong Quan
- School of Physics and Technology, Wuhan University, Wuhan, P.R. China
| | - Jian Zhu
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, P.R. China.,Shandong Medical Imaging and Radiotherapy Engineering Center, Jinan, P.R. China.,Shandong Key Laboratory of Digital Medicine and Computer Assisted Surgery, The Affiliated Hospital of Qingdao University, Qingdao, P.R. China
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Wood S, Santini T, Krishnamurthy N, Martins T, Farhat N, Ibrahim TS. A comprehensive electromagnetic evaluation of an MRI anthropomorphic head phantom. NMR Biomed 2021; 34:e4441. [PMID: 33354828 PMCID: PMC8080257 DOI: 10.1002/nbm.4441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
Electromagnetic simulations are an important tool for the safety assessment of RF coils. They are a useful resource for MRI RF coil designers, especially when complemented with experimental measurements and testing using physical phantoms. Regular-shaped (spherical/cylindrical) homogeneous phantoms are the MRI standard for RF testing but are somewhat inaccurate when compared with anthropomorphic anatomies, especially at high frequencies. In this work, using a recently developed anthropomorphic heterogeneous human head phantom, studies were performed to analyze the scattering parameters (S-parameters) and the electric and magnetic field distributions using (1) the B1+ field mapping method on a 7 T human MRI scanner and (2) numerical full-wave electromagnetic simulations. All studies used the following: a recently developed six-compartment refillable 3D-printed anthropomorphic head phantom (developed from MRI scans obtained in vivo), where the phantom itself is filled in its entirety with either heterogeneous loading, or homogeneous brain or water loading, in vivo imaging, and a commercial homogeneous spherical water phantom. Our results determined that the calculated S-parameters for all the anthropomorphic head phantom models were comparable to the model that is based on the volunteer (within 17% difference of the reflection coefficient value) but differed for the commercial homogeneous spherical water phantom (within 45% difference). The experimentally measured B1+ field maps of the anthropomorphic heterogeneous and homogeneous brain head phantoms were most comparable to the in vivo measured values. The numerical simulations also show that both the anthropomorphic homogeneous water and brain phantom models were less accurate in terms of electric field intensities/distributions when compared with the segmented in-vivo-based head model and the anthropomorphic heterogeneous head phantom model. The presented data highlights the differences between the physical phantoms/phantom models, and the in vivo measurements/segmented in-vivo-based head model. The results demonstrate the usefulness of 3D-printed anthropomorphic phantoms for RF coil evaluation and testing.
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Affiliation(s)
- Sossena Wood
- University of Pittsburgh, Bioengineering, Pittsburgh, PA, USA
- Carnegie Mellon University, Biomedical Engineering, Pittsburgh, PA, USA
| | - Tales Santini
- University of Pittsburgh, Bioengineering, Pittsburgh, PA, USA
| | | | - Tiago Martins
- University of Pittsburgh, Bioengineering, Pittsburgh, PA, USA
| | - Nadim Farhat
- University of Pittsburgh, Bioengineering, Pittsburgh, PA, USA
| | - Tamer S. Ibrahim
- University of Pittsburgh, Bioengineering, Pittsburgh, PA, USA
- University of Pittsburgh, Psychiatry, Pittsburgh, PA, USA
- University of Pittsburgh, Radiology, Pittsburgh, PA, USA
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21
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Babaloui S, Jafari S, Polak W, Ghorbani M, Hubbard MW, Lohstroh A, Shirazi A, Jaberi R. Development of a novel and low-cost anthropomorphic pelvis phantom for 3D dosimetry in radiotherapy. J Contemp Brachytherapy 2020; 12:470-9. [PMID: 33299436 DOI: 10.5114/jcb.2020.100380] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/29/2020] [Indexed: 12/01/2022] Open
Abstract
Purpose The aim of this study was to construct a low-cost, anthropomorphic, and 3D-printed pelvis phantom and evaluate the feasibility of its use to perform 3D dosimetry with commercially available bead thermoluminescent dosimeters (TLDs). Material and methods A novel anthropomorphic female phantom was developed with all relevant pelvic organs to position the bead TLDs. Organs were 3D-printed using acrylonitrile butadiene styrene. Phantom components were confirmed to have mass density and computed tomography (CT) numbers similar to relevant tissues. To find out clinically required spatial resolution of beads to cause no perturbation effect, TLDs were positioned with 2.5, 5, and 7.5 mm spacing on the surface of syringe. After taking a CT scan and creating a 4-field conformal radiotherapy plan, 3 dose planes were extracted from the treatment planning system (TPS) at different depths. By using a 2D-gamma analysis, the TPS reports were compared with and without the presence of beads. Moreover, the bead TLDs were placed on the organs’ surfaces of the pelvis phantom and exposed to high-dose-rate (HDR) 60Co source. TLDs’ readouts were compared with the TPS calculated doses, and dose surface histograms (DSHs) of organs were plotted. Results 3D-printed phantom organs agreed well with body tissues regarding both their design and radiation properties. Furthermore, the 2D-gamma analysis on the syringe showed more than 99% points passed 3%- and 3-mm criteria at different depths. By calculating the integral dose of DSHs, the percentage differences were –1.5%, 2%, 5%, and 10% for uterus, rectum, bladder, and sigmoid, respectively. Also, combined standard uncertainty was estimated as 3.5% (k = 1). Conclusions A customized pelvis phantom was successfully built and assessed to confirm properties similar to body tissues. Additionally, no significant perturbation effect with different bead resolutions was presented by the external TPS, with 0.1 mm dose grid resolution.
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22
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Savazzi M, Abedi S, Ištuk N, Joachimowicz N, Roussel H, Porter E, O'Halloran M, Costa JR, Fernandes CA, Felício JM, Conceição RC. Development of an Anthropomorphic Phantom of the Axillary Region for Microwave Imaging Assessment. Sensors (Basel) 2020; 20:E4968. [PMID: 32887340 DOI: 10.3390/s20174968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/08/2020] [Accepted: 08/31/2020] [Indexed: 12/24/2022]
Abstract
We produced an anatomically and dielectrically realistic phantom of the axillary region to enable the experimental assessment of Axillary Lymph Node (ALN) imaging using microwave imaging technology. We segmented a thoracic Computed Tomography (CT) scan and created a computer-aided designed file containing the anatomical configuration of the axillary region. The phantom comprises five 3D-printed parts representing the main tissues of interest of the axillary region for the purpose of microwave imaging: fat, muscle, bone, ALNs, and lung. The phantom allows the experimental assessment of multiple anatomical configurations, by including ALNs of different size, shape, and number in several locations. Except for the bone mimicking organ, which is made of solid conductive polymer, we 3D-printed cavities to represent the fat, muscle, ALN, and lung and filled them with appropriate tissue-mimicking liquids. Existing studies about complex permittivity of ALNs have reported limitations. To address these, we measured the complex permittivity of both human and animal lymph nodes using the standard open-ended coaxial-probe technique, over the 0.5 GHz–8.5 GHz frequency band, thus extending current knowledge on dielectric properties of ALNs. Lastly, we numerically evaluated the effect of the polymer which constitutes the cavities of the phantom and compared it to the realistic axillary region. The results showed a maximum difference of 7 dB at 4 GHz in the electric field magnitude coupled to the tissues and a maximum of 10 dB difference in the ALN response. Our results showed that the phantom is a good representation of the axillary region and a viable tool for pre-clinical assessment of microwave imaging technology.
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23
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Han EY, Diagaradjane P, Luo D, Ding Y, Kalaitzakis G, Zoros E, Zourari K, Boursianis T, Pappas E, Wen Z, Wang J, Briere TM. Validation of PTV margin for Gamma Knife Icon frameless treatment using a PseudoPatient® Prime anthropomorphic phantom. J Appl Clin Med Phys 2020; 21:278-285. [PMID: 32786141 PMCID: PMC7497928 DOI: 10.1002/acm2.12997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/28/2020] [Accepted: 06/23/2020] [Indexed: 11/09/2022] Open
Abstract
The Gamma Knife Icon allows the treatment of brain tumors mask-based single-fraction or fractionated treatment schemes. In clinic, uniform axial expansion of 1 mm around the gross tumor volume (GTV) and a 1.5 mm expansion in the superior and inferior directions are used to generate the planning target volume (PTV). The purpose of the study was to validate this margin scheme with two clinical scenarios: (a) the patient's head remaining right below the high-definition motion management (HDMM) threshold, and (b) frequent treatment interruptions followed by plan adaptation induced by large pitch head motion. A remote-controlled head assembly was used to control the motion of a PseudoPatient® Prime head phantom; for dosimetric evaluations, an ionization chamber, EBT3 films, and polymer gels were used. These measurements were compared with those from the Gamma Knife plan. For the absolute dose measurements using an ionization chamber, the percentage differences for both targets were less than 3.0% for all scenarios, which was within the expected tolerance. For the film measurements, the two-dimensional (2D) gamma index with a 2%/2 mm criterion showed the passing rates of ≥87% in all scenarios except the scenario 1. The results of Gel measurements showed that GTV (D100 ) was covered by the prescription dose and PTV (D95 ) was well above the planned dose by up to 5.6% and the largest geometric PTV offset was 0.8 mm for all scenarios. In conclusion, the current margin scheme with HDMM setting is adequate for a typical patient's intrafractional motion.
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Affiliation(s)
- Eun Young Han
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Parmeswaran Diagaradjane
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dershan Luo
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yao Ding
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Emmanouil Zoros
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Kyveli Zourari
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Evangelos Pappas
- Department of Biomedical Sciences, Radiology & Radiotherapy Sector, University of West Attica, Athens, Greece
| | - Zhifei Wen
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jihong Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tina Marie Briere
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Acciavatti RJ, Cohen EA, Maghsoudi OH, Gastounioti A, Pantalone L, Hsieh MK, Barufaldi B, Bakic PR, Chen J, Conant EF, Kontos D, Maidment ADA. Calculation of Radiomic Features to Validate the Textural Realism of Physical Anthropomorphic Phantoms for Digital Mammography. Proc SPIE Int Soc Opt Eng 2020; 11513:1151309. [PMID: 37818096 PMCID: PMC10564085 DOI: 10.1117/12.2564363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
In this paper, radiomic features are used to validate the textural realism of two anthropomorphic phantoms for digital mammography. One phantom was based off a computational breast model; it was 3D printed by CIRS (Computerized Imaging Reference Systems, Inc., Norfolk, VA) under license from the University of Pennsylvania. We investigate how the textural realism of this phantom compares against a phantom derived from an actual patient's mammogram ("Rachel", Gammex 169, Madison, WI). Images of each phantom were acquired at three kV in 1 kV increments using auto-time technique settings. Acquisitions at each technique setting were repeated twice, resulting in six images per phantom. In the raw ("FOR PROCESSING") images, 341 features were calculated; i.e., gray-level histogram, co-occurrence, run length, fractal dimension, Gabor Wavelet, local binary pattern, Laws, and co-occurrence Laws features. Features were also calculated in a negative screening population. For each feature, the middle 95% of the clinical distribution was used to evaluate the textural realism of each phantom. A feature was considered realistic if all six measurements in the phantom were within the middle 95% of the clinical distribution. Otherwise, a feature was considered unrealistic. More features were actually found to be realistic by this definition in the CIRS phantom (305 out of 341 features or 89.44%) than in the phantom derived from a specific patient's mammogram (261 out of 341 features or 76.54%). We conclude that the texture is realistic overall in both phantoms.
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Affiliation(s)
- Raymond J Acciavatti
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Eric A Cohen
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Omid Haji Maghsoudi
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Aimilia Gastounioti
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Lauren Pantalone
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Meng-Kang Hsieh
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Bruno Barufaldi
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Predrag R Bakic
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Jinbo Chen
- University of Pennsylvania, Department of Epidemiology, Biostatistics, & Informatics, 423 Guardian Drive, Philadelphia, PA 19104
| | - Emily F Conant
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Despina Kontos
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
| | - Andrew D A Maidment
- University of Pennsylvania, Department of Radiology, 3400 Spruce Street, Philadelphia PA 19104
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Curto S, Aklan B, Mulder T, Mils O, Schmidt M, Lamprecht U, Peller M, Wessalowski R, Lindner LH, Fietkau R, Zips D, Bellizzi GG, van Holthe N, Franckena M, Paulides MM, van Rhoon GC. Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom. Cancers (Basel) 2019; 11:E1709. [PMID: 31684057 DOI: 10.3390/cancers11111709] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/22/2019] [Accepted: 10/30/2019] [Indexed: 01/10/2023] Open
Abstract
Clinical outcome of hyperthermia depends on the achieved target temperature, therefore target conformal heating is essential. Currently, invasive temperature probe measurements are the gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast, magnetic resonance thermometry (MRT) provides unique capabilities to non-invasively measure the 3D-temperature. This study investigates MRT accuracy for MR-hyperthermia hybrid systems located at five European institutions while heating a centric or eccentric target in anthropomorphic phantoms with pelvic and spine structures. Scatter plots, root mean square error (RMSE) and Bland-Altman analysis were used to quantify accuracy of MRT compared to high resistance thermistor probe measurements. For all institutions, a linear relation between MRT and thermistor probes measurements was found with R2 (mean ± standard deviation) of 0.97 ± 0.03 and 0.97 ± 0.02, respectively for centric and eccentric heating targets. The RMSE was found to be 0.52 ± 0.31 °C and 0.30 ± 0.20 °C, respectively. The Bland-Altman evaluation showed a mean difference of 0.46 ± 0.20 °C and 0.13 ± 0.08 °C, respectively. This first multi-institutional evaluation of MR-hyperthermia hybrid systems indicates comparable device performance and good agreement between MRT and thermistor probes measurements. This forms the basis to standardize treatments in multi-institution studies of MR-guided hyperthermia and to elucidate thermal dose-effect relations.
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Hoerner MR, Maynard MR, Rajon DA, Bova FJ, Hintenlang DE. Three-Dimensional Printing for Construction of Tissue-Equivalent Anthropomorphic Phantoms and Determination of Conceptus Dose. AJR Am J Roentgenol 2018; 211:1283-90. [PMID: 30354270 DOI: 10.2214/AJR.17.19489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to develop a road map for rapid construction of anthropomorphic phantoms from computational human phantoms for use in diagnostic imaging dosimetry studies. These phantoms are ideal for performing pregnant-patient dosimetry because the phantoms imitate the size and attenuation properties of an average-sized pregnant woman for multiple gestational periods. MATERIALS AND METHODS The method was derived from methods and materials previously described but adapted for 3D printing technology. A 3D printer was used to transform computational models into a physical duplicate with small losses in spatial accuracy and to generate tissue-equivalent materials characterized for diagnostic energy x-rays. A series of pregnant abdomens were selected as prototypes because of their large size and complex modeling. The process involved the following steps: segmentation of anatomy used for modeling; transformation of the computational model into a printing file format; preparation, characterization, and introduction of phantom materials; and model removal and phantom assembly. RESULTS The density of the homogenized soft tissue-equivalent substitute was optimized by combining 9.0% by weight of urethane filler powder and 91.0% urethane polymer, which resulted in a mean density of 1.041 g/cm3 measured over 20 samples. Density varied among all of the samples by 0.0026 g/cm3. The total variation in density was 0.00261 g/cm3. The half-value layer of the bone material was measured to be 1.7 mm of bone material at 120 kVp and when simulated by use of the density of the bone tissue-equivalent substitute (1.60 g/cm3) was determined to be 1.61 mm of bone tissue. For dosimetry purposes the phantom provided excellent results for evaluating a site's protocol based on scan range. CONCLUSION The 3D printing technology is applicable to the fabrication of phantoms used for performing dosimetry. The tissue-equivalent materials used to substitute for the soft tissue were developed to be highly adaptable for optimization based on the dosimetry application. Use of this method resulted in more automated phantom construction with decreased construction time and increased out-of-slice spatial resolution of the phantoms.
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Glenn MC, Hernandez V, Saez J, Followill DS, Howell RM, Pollard-Larkin JM, Zhou S, Kry SF. Treatment plan complexity does not predict IROC Houston anthropomorphic head and neck phantom performance. Phys Med Biol 2018; 63:205015. [PMID: 30230475 PMCID: PMC6287268 DOI: 10.1088/1361-6560/aae29e] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous works indicate that intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans that are highly complex may produce more errors in dose calculation and treatment delivery. Multiple complexity metrics have been proposed and associated with IMRT QA results, but their relationships with plan performance using in situ dose measurements have not been thoroughly investigated. This study aimed to evaluate the relationships between IMRT treatment plan complexity and anthropomorphic phantom performance in order to assess the extent to which plan complexity is related to dosimetric performance in the IROC phantom credentialing program. Sixteen complexity metrics, including the modulation complexity score (MCS), several modulation indices, and total monitor units (MU) delivered, were evaluated for 343 head and neck phantom irradiations, comprising both IMRT (step-and-shoot and sliding window techniques) and VMAT. Spearman's correlations were used to explore the relationship between complexity and plan performance, as measured by the dosimetric differences between the treatment planning system (TPS) and thermoluminescent dosimeter (TLD) measurement, as well as film gamma analysis. Relationships were likewise determined for several combinations of subpopulations, based on the linear accelerator model, TPS used, and delivery modality. Evaluation of the complexity metrics presented here yielded no significant relationships (p > 0.01, Bonferroni-corrected) and all correlations were weak (less than ±0.30). These results indicate that complexity metrics have limited predictive utility in assessing plan performance in multi-institutional comparisons of IMRT plans. Other factors affecting plan accuracy, such as dosimetric modeling or multileaf collimator (MLC) performance, should be investigated to determine a more probable cause for dose delivery errors.
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Affiliation(s)
- Mallory C. Glenn
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Victor Hernandez
- Department of Medical Physics, Hospital Universitari Sant Joan de Reus, Tarragona, Spain
| | - Jordi Saez
- Department of Radiation Oncology, Hospital Clmic de Barcelona, Barcelona, Spain
| | - David S. Followill
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Rebecca M. Howell
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Julianne M. Pollard-Larkin
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Shouhao Zhou
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Stephen F. Kry
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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Radojcic ĐS, Rajlic D, Casar B, Kolacio MS, Obajdin N, Faj D, Jurkovic S. Evaluation of two-dimensional dose distributions for pre-treatment patient-specific IMRT dosimetry. Radiol Oncol 2018; 52:346-352. [PMID: 30210046 PMCID: PMC6137356 DOI: 10.2478/raon-2018-0019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/13/2018] [Indexed: 11/22/2022] Open
Abstract
Background The accuracy of dose calculation is crucial for success of the radiotherapy treatment. One of the methods that represent the current standard for patient-specific dosimetry is the evaluation of dose distributions measured with an ionization chamber array inside a homogeneous phantom using gamma method. Nevertheless, this method does not replicate the realistic conditions present when a patient is undergoing therapy. Therefore, to more accurately evaluate the treatment planning system (TPS) capabilities, gamma passing rates were examined for beams of different complexity passing through inhomogeneous phantoms. Materials and methods The research was performed using Siemens Oncor Expression linear accelerator, Siemens Somatom Open CT simulator and Elekta Monaco TPS. A 2D detector array was used to evaluate dose distribution accuracy in homogeneous, semi-anthropomorphic and anthropomorphic phantoms. Validation was based on gamma analysis with 3%/3mm and 2%/2mm criteria, respectively. Results Passing rates of the complex dose distributions degrade depending on the thickness of non-water equivalent material. They also depend on dose reporting mode used. It is observed that the passing rate decreases with plan complexity. Comparison of the data for all set-ups of semi-anthropomorphic and anthropomorphic phantoms shows that passing rates are higher in the anthropomorphic phantom. Conclusions Presented results raise a question of possible limits of dose distribution verification in assessment of plan delivery quality. Consequently, good results obtained using standard patient specific dosimetry methodology do not guarantee the accuracy of delivered dose distribution in real clinical cases.
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Affiliation(s)
| | - David Rajlic
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
| | - Bozidar Casar
- Institute of Oncology LJubljana, Department of Radiation Physics, Ljubljana, Slovenia
| | | | - Nevena Obajdin
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
| | - Dario Faj
- Faculty of Medicine, University of Osijek, Osijek, Croatia
- Faculty of Dental Medicine and Health, University of Osijek, Osijek, Croatia
| | - Slaven Jurkovic
- University Hospital Rijeka, Medical Physics Department, Rijeka, Croatia
- Department of Medical Physics and Biophysics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Rodríguez Pérez S, Marshall NW, Struelens L, Bosmans H. Characterization and validation of the thorax phantom Lungman for dose assessment in chest radiography optimization studies. J Med Imaging (Bellingham) 2018; 5:013504. [PMID: 29430474 DOI: 10.1117/1.jmi.5.1.013504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/11/2018] [Indexed: 11/14/2022] Open
Abstract
This work concerns the validation of the Kyoto-Kagaku thorax anthropomorphic phantom Lungman for use in chest radiography optimization. The equivalence in terms of polymethyl methacrylate (PMMA) was established for the lung and mediastinum regions of the phantom. Patient chest examination data acquired under automatic exposure control were collated over a 2-year period for a standard x-ray room. Parameters surveyed included exposure index, air kerma area product, and exposure time, which were compared with Lungman values. Finally, a voxel model was developed by segmenting computed tomography images of the phantom and implemented in PENELOPE/penEasy Monte Carlo code to compare phantom tissue-equivalent materials with materials from ICRP Publication 89 in terms of organ dose. PMMA equivalence varied depending on tube voltage, from 9.5 to 10.0 cm and from 13.5 to 13.7 cm, for the lungs and mediastinum regions, respectively. For the survey, close agreement was found between the phantom and the patients' median values (deviations lay between 8% and 14%). Differences in lung doses, an important organ for optimization in chest radiography, were below 13% when comparing the use of phantom tissue-equivalent materials versus ICRP materials. The study confirms the value of the Lungman for chest optimization studies.
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Affiliation(s)
- Sunay Rodríguez Pérez
- SCK CEN, Radiation Protection Dosimetry and Calibration, Mol, Belgium.,KU Leuven, Medical Physics and Quality Assessment, Leuven, Belgium
| | | | - Lara Struelens
- SCK CEN, Radiation Protection Dosimetry and Calibration, Mol, Belgium
| | - Hilde Bosmans
- UZ Gasthuisberg, Department of Radiology, Leuven, Belgium
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Stepusin EJ, Long DJ, Ficarrotta KR, Hintenlang DE, Bolch WE. Physical validation of a Monte Carlo-based, phantom-derived approach to computed tomography organ dosimetry under tube current modulation. Med Phys 2017; 44:5423-5432. [PMID: 28688151 DOI: 10.1002/mp.12461] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/26/2017] [Accepted: 06/30/2017] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To physically validate the accuracy of a Monte Carlo-based, phantom-derived methodology for computed tomography (CT) dosimetry that utilizes organ doses from precomputed axial scans and that accounts for tube current modulation (TCM). METHODS The output of a Toshiba Aquilion ONE CT scanner was modeled, based on physical measurement, in the Monte Carlo radiation transport code MCNPX (v2.70). CT examinations were taken of two anthropomorphic phantoms representing pediatric and adult patients (15-yr-old female and adult male) at various energies, in which physical organ dose measurements were made using optically stimulated luminescence dosimeters (OSLDs). These exams (chest-abdomen-pelvis) were modeled using organ dose data obtained from the computationally equivalent phantom of each anthropomorphic phantom. TCM was accounted for by weighting all organ dose contributions by both the relative attenuation of the phantom and the image-derived mA value (from the DICOM header) at the same z-extent (cranial-caudal direction) of the axial dose data. RESULTS The root mean squares of percent difference in organ dose when comparing the physical organ dose measurements to the computational estimates were 21.2, 12.1, and 15.1% for the uniform (no attenuation weighting), weighted (computationally derived), and image-based methodologies, respectively. CONCLUSIONS Overall, these data suggest that the Monte Carlo-based dosimetry presented in this work is viable for CT dosimetry. Additionally, for CT exams with TCM, local attenuation weighting of organ dose contributions from precomputed axial dosimetry libraries increases organ dose accuracy.
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Affiliation(s)
- Elliott J Stepusin
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6131, USA
| | - Daniel J Long
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA
| | - Kayla R Ficarrotta
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6131, USA
| | - David E Hintenlang
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6131, USA
| | - Wesley E Bolch
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, 32611-6131, USA
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Nikupaavo U, Kaasalainen T, Reijonen V, Ahonen SM, Kortesniemi M. Lens dose in routine head CT: comparison of different optimization methods with anthropomorphic phantoms. AJR Am J Roentgenol 2015; 204:117-23. [PMID: 25539246 DOI: 10.2214/AJR.14.12763] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to study different optimization methods for reducing eye lens dose in head CT. MATERIALS AND METHODS Two anthropomorphic phantoms were scanned with a routine head CT protocol for evaluation of the brain that included bismuth shielding, gantry tilting, organ-based tube current modulation, or combinations of these techniques. Highsensitivity metal oxide semiconductor field effect transistor dosimeters were used to measure local equivalent doses in the head region. The relative changes in image noise and contrast were determined by ROI analysis. RESULTS The mean absorbed lens doses varied from 4.9 to 19.7 mGy and from 10.8 to 16.9 mGy in the two phantoms. The most efficient method for reducing lens dose was gantry tilting, which left the lenses outside the primary radiation beam, resulting in an approximately 75% decrease in lens dose. Image noise decreased, especially in the anterior part of the brain. The use of organ-based tube current modulation resulted in an approximately 30% decrease in lens dose. However, image noise increased as much as 30% in the posterior and central parts of the brain. With bismuth shields, it was possible to reduce lens dose as much as 25%. CONCLUSION Our results indicate that gantry tilt, when possible, is an effective method for reducing exposure of the eye lenses in CT of the brain without compromising image quality. Measurements in two different phantoms showed how patient geometry affects the optimization. When lenses can only partially be cropped outside the primary beam, organ-based tube current modulation or bismuth shields can be useful in lens dose reduction.
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Winslow JF, Hyer DE, Fisher RF, Tien CJ, Hintenlang DE. Construction of anthropomorphic phantoms for use in dosimetry studies. J Appl Clin Med Phys 2009; 10:195-204. [PMID: 19692982 PMCID: PMC5720556 DOI: 10.1120/jacmp.v10i3.2986] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 04/27/2009] [Accepted: 04/27/2009] [Indexed: 11/23/2022] Open
Abstract
This paper reports on the methodology and materials used to construct anthropomorphic phantoms for use in dosimetry studies, improving on methods and materials previously described by Jones et al. [Med Phys. 2006;33(9):3274-82]. To date, the methodology described has been successfully used to create a series of three different adult phantoms at the University of Florida (UF). All phantoms were constructed in 5 mm transverse slices using materials designed to mimic human tissue at diagnostic photon energies: soft tissue-equivalent substitute (STES), lung tissue-equivalent substitute (LTES), and bone tissue-equivalent substitute (BTES). While the formulation for BTES remains unchanged from the previous epoxy resin compound developed by Jones et al. [Med Phys. 2003;30(8):2072-81], both the STES and LTES were redesigned utilizing a urethane based compound which forms a pliable tissue-equivalent material. These urethane based materials were chosen in part for improved phantom durability and easier accommodation of real-time dosimeters. The production process has also been streamlined with the use of an automated machining system to create molds for the phantom slices from bitmap images based on the original segmented computed tomography (CT) datasets. Information regarding the new tissue-equivalent materials as well as images of the construction process and completed phantom are included.
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Affiliation(s)
- James F. Winslow
- Department of Nuclear and Radiological EngineeringUniversity of FloridaGainesvilleFloridaUSA32611‐8300
| | - Daniel E. Hyer
- Department of Nuclear and Radiological EngineeringUniversity of FloridaGainesvilleFloridaUSA32611‐8300
| | - Ryan F. Fisher
- Department of Nuclear and Radiological EngineeringUniversity of FloridaGainesvilleFloridaUSA32611‐8300
| | - Christopher J. Tien
- Department of Nuclear and Radiological EngineeringUniversity of FloridaGainesvilleFloridaUSA32611‐8300
| | - David E. Hintenlang
- Department of Nuclear and Radiological EngineeringUniversity of FloridaGainesvilleFloridaUSA32611‐8300
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Svahn T, Hemdal B, Ruschin M, Chakraborty DP, Andersson I, Tingberg A, Mattsson S. Dose reduction and its influence on diagnostic accuracy and radiation risk in digital mammography: an observer performance study using an anthropomorphic breast phantom. Br J Radiol 2007; 80:557-62. [PMID: 17704316 PMCID: PMC2253655 DOI: 10.1259/bjr/29933797] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study aimed to investigate the effect of dose reduction on diagnostic accuracy and radiation risk in digital mammography. Simulated masses and microcalcifications were positioned in an anthropomorphic breast phantom. Thirty digital images, 14 with lesions, 16 without, were acquired of the phantom using a Mammomat Novation (Siemens, Erlangen, Germany) at each of three dose levels. These corresponded to 100%, 50% and 30% of the normally used average glandular dose (AGD; 1.3 mGy for a standard breast). Eight observers interpreted the 90 unprocessed images in a free response study, and the data were analysed with the jackknife free response receiver operating characteristic (JAFROC) method. Observer performance was assessed using the JAFROC figure of merit (FOM). The benefit of radiation risk reduction was estimated based on several risk models. There was no statistically significant difference in performance, as described by the FOM, between the 100% and the 50% dose levels. However, the FOMs for both the 100% and the 50% dose were significantly different from the corresponding quantity for the 30% dose level (F-statistic = 4.95, p-value = 0.01). A dose reduction of 50% would result in three to nine fewer breast cancer fatalities per 100,000 women undergoing annual screening from the age of 40 to 49 years. The results of the study indicate a possibility of reducing the dose to the breast to half the dose level currently used. This has to be confirmed in clinical studies, and possible differences depending on lesion type should be examined further.
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Affiliation(s)
- T Svahn
- Department of Medical Radiation Physics, Lund University, Malmö University Hospital, SE-20502 Malmö, Sweden.
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Howlett SJ, Kron T. Monitor unit calculation for tangential breast treatments: verification in an anthropomorphic phantom. J Appl Clin Med Phys 2002; 3:235-40. [PMID: 12132946 PMCID: PMC5724595 DOI: 10.1120/jacmp.v3i3.2568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2001] [Accepted: 04/24/2002] [Indexed: 11/23/2022] Open
Abstract
This paper presents an anthropomorphic phantom study of dose delivered to a specific point during tangential breast irradiation to verify monitor unit calculations. Measurements were made using a 0.6 cc Farmer type cylindrical ionization chamber in the phantom and compared to calculations made on a three-dimensional radiotherapy treatment planning system using single digitized contour through to multi slice CT data. A large breast phantom was used for a single field size with a combination of open and wedged fields for three different energies (4, 6, and 18 MV). Solid flat phantom measurements were also performed for comparison. Results showed a lower calculated dose than the dose measured for a fixed number of monitor units where the variations were within a range of 0.8% to 4.5%. Differences were larger for the anthropomorphic phantom than the flat phantom. We conclude that little accuracy is gained from CT based monitor unit calculations compared to those based on digitised contours for this breast treatment but that the dose distributions will be affected. This type of test is recommended as one of a large set, in the commissioning and testing procedures for treatment planning systems.
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Affiliation(s)
- Stephen J. Howlett
- Department of Radiation OncologyNewcastle Mater HospitalLocked Bag 7, Hunter Region Mail Centre2310NSWAustralia
| | - Tomas Kron
- Department of Radiation OncologyNewcastle Mater HospitalLocked Bag 7, Hunter Region Mail Centre2310NSWAustralia
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