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A novel‐integrated quality assurance phantom for radiographic and nonradiographic radiotherapy localization and positioning systems
Author(s) -
Yu Amy S.,
Fowler Tyler L.,
Dubrowski Piotr
Publication year - 2018
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.12950
Subject(s) - imaging phantom , quality assurance , fiducial marker , scanner , computer science , nuclear medicine , radiation treatment planning , radiography , digital radiography , computer vision , medical physics , medicine , artificial intelligence , radiation therapy , radiology , external quality assessment , pathology
Purpose Various localization and positioning systems utilizing radiographic or nonradiographic methods have been developed to improve the accuracy of radiation treatment. Each quality assurance ( QA ) procedure requires its own phantom and is independent from each other, so the deviation between each system is unavailable. The purpose of this work is to develop and evaluate a single‐integrated QA phantom for different localization and positioning systems. Methods The integrated phantom was designed in three‐dimensional (3D) CAD software and 3D printed. The phantom was designed with laser alignment marks, a raised letter “S” on the anterior surface for optical surface monitoring system registration, a core for radiofrequency ( RF ) tracking system alignment, eight internal fiducials for image alignment, and an isocentric bearing for Winston–Lutz test. Tilt legs and rotational stage were designed for rotational verification of optical surface mapping system and RF tracking system, respectively. The phantom was scanned using a CT scanner and a QA plan was created. This prototype phantom was evaluated against established QA techniques. Results The QA result between the proposed procedure and established QA technique are 1.12 ± 0.31 and 1.14 ± 0.31 mm, respectively, for RF tracking system and 0.18 ± 0.06 and 0.18 ± 0.05 mm for Winston–Lutz test. There is no significant difference for the QA results between the established QA and proposed procedure ( P > 0.05, t test). The accuracy of rotational verification for surface mapping system and RF tracking system are less than 0.5 and 1° compared the predefined value. The isocenter deviation of each location system is around l mm. Conclusion We have designed and evaluated a novel‐integrated phantom for radiographic and nonradiographic localization and positioning systems for radiotherapy. With this phantom, we will reduce the variation in measurements and simplify the QA procedures.