Christina Sarosiek1, Ethan A DeJongh2, George Coutrakon1, Don F DeJongh2, Kirk L Duffin3, Nicholas T Karonis3,4, Caesar E Ordoñez3, Mark Pankuch5, Victor Rykalin2, John R Winans3, James S Welsh6,7. 1. Department of Physics, Northern Illinois University, DeKalb, IL, 60115, USA. 2. ProtonVDA LLC, Naperville, IL, 60563, USA. 3. Department of Computer Science, Northern Illinois University, DeKalb, IL, 60115, USA. 4. Argonne National Laboratory, Data Science and Learning Division, Argonne, IL, 60439, USA. 5. Northwestern Medicine Chicago Proton Center, Warrenville, IL, 60555, USA. 6. Radiation Oncology Service, Edward Hines Jr VA Medical Center, Hines, IL, 60141, USA. 7. Department of Radiation Oncology, Loyola University Stritch School of Medicine, Maywood, IL, 60153, USA.
Abstract
PURPOSE: Verification of patient-specific proton stopping powers obtained in the patient's treatment position can be used to reduce the distal and proximal margins needed in particle beam planning. Proton radiography can be used as a pretreatment instrument to verify integrated stopping power consistency with the treatment planning CT. Although a proton radiograph is a pixel by pixel representation of integrated stopping powers, the image may also be of high enough quality and contrast to be used for patient alignment. This investigation quantifies the accuracy and image quality of a prototype proton radiography system on a clinical proton delivery system. METHODS: We have developed a clinical prototype proton radiography system designed for integration into efficient clinical workflows. We tested the images obtained by this system for water-equivalent thickness (WET) accuracy, image noise, and spatial resolution. We evaluated the WET accuracy by comparing the average WET and rms error in several regions of interest (ROI) on a proton radiograph of a custom peg phantom. We measured the spatial resolution on a CATPHAN Line Pair phantom and a custom edge phantom by measuring the 10% value of the modulation transfer function (MTF). In addition, we tested the ability to detect proton range errors due to anatomical changes in a patient with a customized CIRS pediatric head phantom and inserts of varying WET placed in the posterior fossae of the brain. We took proton radiographs of the phantom with each insert in place and created difference maps between the resulting images. Integrated proton range was measured from an ROI in the difference maps. RESULTS: We measured the WET accuracy of the proton radiographic images to be ±0.2 mm (0.33%) from known values. The spatial resolution of the images was 0.6 lp/mm on the line pair phantom and 1.13 lp/mm on the edge phantom. We were able to detect anatomical changes producing changes in WET as low as 0.6 mm. CONCLUSION: The proton radiography system produces images with image quality sufficient for pretreatment range consistency verification.
PURPOSE: Verification of patient-specific proton stopping powers obtained in the patient's treatment position can be used to reduce the distal and proximal margins needed in particle beam planning. Proton radiography can be used as a pretreatment instrument to verify integrated stopping power consistency with the treatment planning CT. Although a proton radiograph is a pixel by pixel representation of integrated stopping powers, the image may also be of high enough quality and contrast to be used for patient alignment. This investigation quantifies the accuracy and image quality of a prototype proton radiography system on a clinical proton delivery system. METHODS: We have developed a clinical prototype proton radiography system designed for integration into efficient clinical workflows. We tested the images obtained by this system for water-equivalent thickness (WET) accuracy, image noise, and spatial resolution. We evaluated the WET accuracy by comparing the average WET and rms error in several regions of interest (ROI) on a proton radiograph of a custom peg phantom. We measured the spatial resolution on a CATPHAN Line Pair phantom and a custom edge phantom by measuring the 10% value of the modulation transfer function (MTF). In addition, we tested the ability to detect proton range errors due to anatomical changes in a patient with a customized CIRS pediatric head phantom and inserts of varying WET placed in the posterior fossae of the brain. We took proton radiographs of the phantom with each insert in place and created difference maps between the resulting images. Integrated proton range was measured from an ROI in the difference maps. RESULTS: We measured the WET accuracy of the proton radiographic images to be ±0.2 mm (0.33%) from known values. The spatial resolution of the images was 0.6 lp/mm on the line pair phantom and 1.13 lp/mm on the edge phantom. We were able to detect anatomical changes producing changes in WET as low as 0.6 mm. CONCLUSION: The proton radiography system produces images with image quality sufficient for pretreatment range consistency verification.
Authors: Tia E Plautz; V Bashkirov; V Giacometti; R F Hurley; R P Johnson; P Piersimoni; H F-W Sadrozinski; R W Schulte; A Zatserklyaniy Journal: Med Phys Date: 2016-12 Impact factor: 4.071
Authors: Caesar E Ordoñez; Nicholas T Karonis; Kirk L Duffin; John R Winans; Ethan A DeJongh; Don F DeJongh; George Coutrakon; Nicole F Myers; Mark Pankuch; James S Welsh Journal: J Radiat Oncol Date: 2019-05-25
Authors: Valentina Giacometti; Vladimir A Bashkirov; Pierluigi Piersimoni; Susanna Guatelli; Tia E Plautz; Hartmut F-W Sadrozinski; Robert P Johnson; Andriy Zatserklyaniy; Thomas Tessonnier; Katia Parodi; Anatoly B Rosenfeld; Reinhard W Schulte Journal: Med Phys Date: 2017-03 Impact factor: 4.506
Authors: Don F DeJongh; Ethan A DeJongh; Victor Rykalin; Greg DeFillippo; Mark Pankuch; Andrew W Best; George Coutrakon; Kirk L Duffin; Nicholas T Karonis; Caesar E Ordoñez; Christina Sarosiek; Reinhard W Schulte; John R Winans; Alec M Block; Courtney L Hentz; James S Welsh Journal: Med Phys Date: 2021-11-18 Impact factor: 4.071