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SU‐E‐J‐07: 3‐D Commissioning for An Image‐Guided Small Animal Micro‐Irradiation Platform
Author(s) -
Qian X,
Admovics J,
Wuu C
Publication year - 2013
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 - 10.1118/1.4814219
Subject(s) - isocenter , dosimeter , irradiation , scanner , optics , nuclear medicine , reproducibility , materials science , rotation (mathematics) , dosimetry , physics , radiation , imaging phantom , computer science , medicine , mathematics , artificial intelligence , statistics , nuclear physics
Purpose: In a high resolution image‐guided small animal micro‐irradiation platform, the mouse stage rotation for cone beam CT imaging is perpendicular to the gantry rotation for sub‐millimeter radiation delivery. As such, a 3‐D dosimeter, PRESAGE, can provide an excellent tool for verifying both imaging and irradiation coordinates in one system. Methods: The study was done by using PRESAGE dosimeters and optical scanner. In the small animal platform, both of the mouse stage and the gantry can rotate 360°. Isocentricity and coincidence of the mouse stage and gantry rotations were evaluated with starshots. A dosimeter was placed at the isocenter approximately on the mouse stage. Firstly, the gantry moved to 90° in the irradiation coordinate. The mouse stage rotated 360° while the x‐ray was delivered to the dosimeter at certain angles, then both of the gantry and mouse stage moved back to home position. Secondly, the gantry rotated 360° to deliver micro beams to the dosimeter at certain angles. Thirdly, steps one and two were repeated 3 times using 3 dosimeters to determine short‐term reproducibility. Finally, dosimeters were canned using an optical scanner to get results. Dosimetric measurements were also performed. Results: The gantry isocentricity is 1.09 ± 0.15 mm and the mouse stage rotation isocentricity is about 1.1 ± 0.15 mm. Agreement between the measured isocenters of irradiation and imaging coordinates was determined using each starshots from dosimeters. The short‐term reproducibility test yielded 0.5 ± 0.1 mm between the imaging isocenter and the irradiation isocenter, with a maximum displacement of 0.8 mm. The rest results will be presented. Conclusion: The 3‐D PRESAGE dosimeter can be very useful in precise verification of targeting for a small animal irradiation research. In addition, a single PRESAGE dosimeter can provide 3‐D information in both geometric and dosimetric uncertainty, which is crucial for translational studies.