- Email: [email protected]
A 3D printed phantom for Image Quality Assessment in Cone-beam CT
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L. Gaynor et al. / Physica Medica 52 (2018) 165–182
The apps are also supported by interactive patient preparation booklets. https://doi.org/10.1016/j.ejmp.2018.06.030
Joint Session 15:30–17:00 A 3D printed phantom for Image Quality Assessment in Conebeam CT James O’Halloran a, Paddy Gilligan a, Sinead Cleary b, Susan Maguire a, Gerald O’Connor c, Kirby Downy d, Christoph Kleefeld e a
Mater Private, Ireland University Hospital Galway, Ireland c Killiney Dental, Ireland d 3D Print UK, United Kingdom e NUI Galway, Ireland E-mail address: [email protected] b
Aim. The number of cone-beam scanners in use within medical, therapeutic and dental practices is increasing. Quality assurance standards require the assessment of image quality. Current phantoms are not cost effective or practical. The aim of this work was to create a practical 3D printed phantom to address the quality assurance needs of cone beam units particularly in the dental field. 3D printing has the potential to provide adaptable, reproducible, low cost phantoms for use in the field where offline access to images can be difficult. Materials and methods. A phantom was designed which adhered to the requirements as outlined by the Sedentexct Guidelines. The design was constructed using 3D printing software (Solidworks, USA) to include modules for uniformity, resolution, contrast, geometrical and Hounsfield unit accuracy. A number of models, materials and production techniques were evaluated. Results. A portable robust nylon phantom was created using selective laser sintering. Chambers in the phantom allowed filling with materials for assessment of Hounsfield units. Metal implants allowed assessment of geometric accuracy and potential artefacts. The phantom met the requirements of Sedentexct testing guidelines. The phantom assessed a cone-beam dental CT (Planmeca, Finland), an angiographic CT (Artis Q, Siemens) and a conventional CT (Sensation open, Siemens. Conclusion. 3D printed nylon phantoms can be used to assess image quality and performance in multiple types of volumetric imaging systems. https://doi.org/10.1016/j.ejmp.2018.06.031
Joint Session 15:30–17:00 The introduction of dedicated planning MR-CT fusion for radical radiotherapy of prostate cancer Ciara Lyons a, Lynn Graham b, Bernadette McCafferty a, Darren Brady a, Patrizia Porcu a, Lois McGinley a, Stephen Gilroy a, Aisling Haughey a, Elaine Reilly a a
Department of Oncology, North West Cancer Centre, Australia Department of Radiology, Altnagelvin Area Hospital, United Kingdom E-mail address: [email protected] b
Purpose. Advances in radiotherapy planning and delivery have made target definition increasingly important. While CT images are required for plan calculation, MR fusion is increasingly used to
more accurately define tumour and normal tissue. There is often significant variation seen between diagnostic and therapeutic imaging; hence, MR carried out in the treatment position is desirable. Materials and methods. A multidisciplinary team of diagnostic and therapeutic radiographers, treatment planners, medical physicists and clinicians was convened. Planning MR was integrated into the radiotherapy pathway and carried out in the days immediately following CT simulation. All men underwent identical preparation (administration of a micro-enema and drinking 300 mL of water thirty minutes prior to imaging/treatment). Patients were set up in the treatment position using MR-compatible radiotherapy immobilisation. T2SE axial and sagittal images were acquired (Siemens Aera 1.5T E11, incorporating RT software platforms/LAP Laser Bridge/ Civco RT Indexing Flat couch top/coil bridges), imported into the Eclipse planning system (V13.6, Varian), and fused to the planning CT for volume delineation. Results. The service opened in mid-September 2017. 26 patients were scanned to the end of November 2017. All patients tolerated preparation and imaging without difficulty. Conclusion. This service has been successfully introduced and will shortly expand to include other sites (rectum, lung, head and neck, complex palliative). A study is planned to assess the impact of the addition of MR on target delineation. Additional considerations include the need for dedicated radiology input and the potential role of collaboration with industry with a view to stand-alone MR simulation. https://doi.org/10.1016/j.ejmp.2018.06.032
Optimisation of on-board imaging fluoroscopy Lynn Gaynor, Serena O’Keeffe, Daniel Rossiter, Elaine Tyner, Sarah McDermott, Brendan McClean St. Luke’s Radiation Oncology Network, Ireland E-mail address: [email protected] On-board imaging fluoroscopy is used for localisation of the target immediately prior to external beam radiotherapy. The feature is clinically used for lung stereotactic ablative radiotherapy involving a moving target and high dose per fraction. Use of fluoroscopy is clearly justified, allowing verification that the target is within the field over its range of motion, ensuring the tumour is not under-treated and there is not excessive dose to normal tissue. Commissioning the fluoroscopy features on Varian Clinacs and Varian Truebeams demonstrated that systems are not optimal at installation. The ability to adjust the automatic brightness control settings is not readily available and access required extensive discussions with the manufacturer. The TrueBeam linear accelerator had additional dose reduction features not available on the Clinac. Such features available in clinical mode included the ability to adjust pulse rate settings and add additional titanium filtration This paper will detail the potential for significant patient dose reduction (35 mGy/min to 16 mGy/min Clinac, 75 mGy/min to 8 mGy/min Truebeam) without a clinically significant reduction in image quality. The doses post optimisation are below what would be expected from an image intensifier and slightly higher than what would be typical for a modern flat-panel interventional system. The dose comparisons are made to interventional systems due to the lack of published data in radiotherapy systems. Historically the focus has been on the considerably higher radiotherapy dose, but recent developments and increased use of imaging in therapy has seen increased attention to imaging doses. https://doi.org/10.1016/j.ejmp.2018.06.033
L. Gaynor et al. / Physica Medica 52 (2018) 165–182
The apps are also supported by interactive patient preparation booklets. https://doi.org/10.1016/j.ejmp.2018.06.030
Joint Session 15:30–17:00 A 3D printed phantom for Image Quality Assessment in Conebeam CT James O’Halloran a, Paddy Gilligan a, Sinead Cleary b, Susan Maguire a, Gerald O’Connor c, Kirby Downy d, Christoph Kleefeld e a
Mater Private, Ireland University Hospital Galway, Ireland c Killiney Dental, Ireland d 3D Print UK, United Kingdom e NUI Galway, Ireland E-mail address: [email protected] b
Aim. The number of cone-beam scanners in use within medical, therapeutic and dental practices is increasing. Quality assurance standards require the assessment of image quality. Current phantoms are not cost effective or practical. The aim of this work was to create a practical 3D printed phantom to address the quality assurance needs of cone beam units particularly in the dental field. 3D printing has the potential to provide adaptable, reproducible, low cost phantoms for use in the field where offline access to images can be difficult. Materials and methods. A phantom was designed which adhered to the requirements as outlined by the Sedentexct Guidelines. The design was constructed using 3D printing software (Solidworks, USA) to include modules for uniformity, resolution, contrast, geometrical and Hounsfield unit accuracy. A number of models, materials and production techniques were evaluated. Results. A portable robust nylon phantom was created using selective laser sintering. Chambers in the phantom allowed filling with materials for assessment of Hounsfield units. Metal implants allowed assessment of geometric accuracy and potential artefacts. The phantom met the requirements of Sedentexct testing guidelines. The phantom assessed a cone-beam dental CT (Planmeca, Finland), an angiographic CT (Artis Q, Siemens) and a conventional CT (Sensation open, Siemens. Conclusion. 3D printed nylon phantoms can be used to assess image quality and performance in multiple types of volumetric imaging systems. https://doi.org/10.1016/j.ejmp.2018.06.031
Joint Session 15:30–17:00 The introduction of dedicated planning MR-CT fusion for radical radiotherapy of prostate cancer Ciara Lyons a, Lynn Graham b, Bernadette McCafferty a, Darren Brady a, Patrizia Porcu a, Lois McGinley a, Stephen Gilroy a, Aisling Haughey a, Elaine Reilly a a
Department of Oncology, North West Cancer Centre, Australia Department of Radiology, Altnagelvin Area Hospital, United Kingdom E-mail address: [email protected] b
Purpose. Advances in radiotherapy planning and delivery have made target definition increasingly important. While CT images are required for plan calculation, MR fusion is increasingly used to
more accurately define tumour and normal tissue. There is often significant variation seen between diagnostic and therapeutic imaging; hence, MR carried out in the treatment position is desirable. Materials and methods. A multidisciplinary team of diagnostic and therapeutic radiographers, treatment planners, medical physicists and clinicians was convened. Planning MR was integrated into the radiotherapy pathway and carried out in the days immediately following CT simulation. All men underwent identical preparation (administration of a micro-enema and drinking 300 mL of water thirty minutes prior to imaging/treatment). Patients were set up in the treatment position using MR-compatible radiotherapy immobilisation. T2SE axial and sagittal images were acquired (Siemens Aera 1.5T E11, incorporating RT software platforms/LAP Laser Bridge/ Civco RT Indexing Flat couch top/coil bridges), imported into the Eclipse planning system (V13.6, Varian), and fused to the planning CT for volume delineation. Results. The service opened in mid-September 2017. 26 patients were scanned to the end of November 2017. All patients tolerated preparation and imaging without difficulty. Conclusion. This service has been successfully introduced and will shortly expand to include other sites (rectum, lung, head and neck, complex palliative). A study is planned to assess the impact of the addition of MR on target delineation. Additional considerations include the need for dedicated radiology input and the potential role of collaboration with industry with a view to stand-alone MR simulation. https://doi.org/10.1016/j.ejmp.2018.06.032
Optimisation of on-board imaging fluoroscopy Lynn Gaynor, Serena O’Keeffe, Daniel Rossiter, Elaine Tyner, Sarah McDermott, Brendan McClean St. Luke’s Radiation Oncology Network, Ireland E-mail address: [email protected] On-board imaging fluoroscopy is used for localisation of the target immediately prior to external beam radiotherapy. The feature is clinically used for lung stereotactic ablative radiotherapy involving a moving target and high dose per fraction. Use of fluoroscopy is clearly justified, allowing verification that the target is within the field over its range of motion, ensuring the tumour is not under-treated and there is not excessive dose to normal tissue. Commissioning the fluoroscopy features on Varian Clinacs and Varian Truebeams demonstrated that systems are not optimal at installation. The ability to adjust the automatic brightness control settings is not readily available and access required extensive discussions with the manufacturer. The TrueBeam linear accelerator had additional dose reduction features not available on the Clinac. Such features available in clinical mode included the ability to adjust pulse rate settings and add additional titanium filtration This paper will detail the potential for significant patient dose reduction (35 mGy/min to 16 mGy/min Clinac, 75 mGy/min to 8 mGy/min Truebeam) without a clinically significant reduction in image quality. The doses post optimisation are below what would be expected from an image intensifier and slightly higher than what would be typical for a modern flat-panel interventional system. The dose comparisons are made to interventional systems due to the lack of published data in radiotherapy systems. Historically the focus has been on the considerably higher radiotherapy dose, but recent developments and increased use of imaging in therapy has seen increased attention to imaging doses. https://doi.org/10.1016/j.ejmp.2018.06.033