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SU‐GG‐T‐348: Development of a Precise Position‐Controlled Moving Phantom
Author(s) -
Mizuno K,
Nakae K,
Okamoto M,
Sasaki H,
Yoshiura K,
Uozumi K,
Mochiduki T,
Demachi K,
Uesaka M
Publication year - 2010
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 - 10.1118/1.3468745
Subject(s) - imaging phantom , physics , thorax (insect anatomy) , position (finance) , motion (physics) , nuclear medicine , medical imaging , biomedical engineering , displacement (psychology) , optics , computer science , artificial intelligence , medicine , anatomy , finance , classical mechanics , economics , psychology , psychotherapist
Purpose : Current commercially available moving phantoms are limited in their motions and accuracy of positions. The purpose of this study is to develop a moving phantom with highly accurate position control (error less than 0.2 mm) in 3 directions so that it can reproduce most of patients' tumor motions obtained by 4D‐CT. Method and Materials : The moving phantom consisted of two parts: thorax phantom and 3D‐axial control unit. The thorax phantom was made of transparent resin, which has an electron density of 1.04. The plaster bones were structured by ink‐jet printing method, and were embedded in the resin. The 3D‐axial control unit was designed to achieve any motion less than 10 cm/sec in x, y and z directions in the region of 150×350×250 mm which was a cavity in the thorax phantom. Two acryl hemispheres with a radius of 1 cm were set on the tip of the 3D‐axial control unit. The motion imitating respiratory tumor motion or sine curve was input, and the motion of the target was measured by a laser displacement gauge to evaluate the accuracy. The target motion was also captured by conventional CT and CBCT to evaluate the performance. Results : The target motion was as accurate as less than 0.1mm in the case of sine waves (1 cm, 12 bpm). In the case of patient's tumor motion (up to 7 mm, 7.5 bpm), although the motion was not modified with smoothing, the error was less than 0.2 mm. The conventional CT and CBCT images reflected the motion of the target. Conclusions : We developed a novel moving phantom with a high accuracy in position control. This moving phantom could be used for evaluation of 4DRT techniques.