Room: AAPM ePoster Library
Purpose: Decimal3D (dotDecimal, Sanford, FL) is a 3D scanning system utilizing optical scanning technology to produce a dimensionally accurate rendering of the patient’s treatment area. The system utilizes a stereoscopic camera and iPad to generate a 3D object of the patient with a texture map enabling digitization of the treatment area and generation of electron apertures used for treatment. The purpose of this work was to validate the accuracy of the cutout and beam geometry coordinate system.
Methods: Thorax and 3D printed phantoms were used to define regions of interest (ROIs) representing intended treatment fields. Printed phantoms consisted of a fixed base and a removable template surfaces for multiple ROI designs normal to beam incidence. ROI shapes ranged from simple circles to complex concave shapes. The Decimal3D scanner generated a rendering of each phantom and ROI, with the ROI digitized as an electron aperture in the Decimal3D software after determining cone size, gantry angle, collimator angle, couch rotation, and SSD. The digitized apertures were sent to dotDecimal for electron cutout fabrication. Verification consisted of reproducing each phantom setup with planned settings and confirming ROI and light field congruence.
Results: Comparison of the light field produced by the electron cutout and the treatment field contour showed good agreement with a maximum deviation of 2 mm, which is within clinical tolerance of electron treatments. All planned couch, gantry, and collimator angles matched those necessary for accurate treatment positioning with SSD tested via magnification.
Conclusion: Pre-clinical verification of the Decimal3D scanner showed good agreement between the produced cutout and the expected treatment field. Decimal3D coordinate system matched the expected delivery coordinate system. Some phantoms scans were completed outside of the treatment vault and verification tests were performed in the vault in an effort to perform clinical electron simulations without requiring machine time.