TY  - JOUR
AU  - Harris, T. C.
AU  - Seco, J.
AU  - Ferguson, D.
AU  - Jacobson, M.
AU  - Myronakis, M.
AU  - Lozano, I Valencia
AU  - Lehmann, M.
AU  - Huber, P.
AU  - Fueglistaller, R.
AU  - Morf, D.
AU  - Mamon, H. J.
AU  - Mancias, J. D.
AU  - Martin, N. E.
AU  - Berbeco, R. I.
TI  - Improvements in beam's eye view fiducial tracking using a novel multilayer imager.
JO  - Physics in medicine and biology
VL  - 66
IS  - 15
SN  - 1361-6560
CY  - Bristol
PB  - IOP Publ.
M1  - DKFZ-2021-01700
SP  - 155007
PY  - 2021
N1  - #EA:E041#
AB  - Purpose.Electronic portal image devices (EPIDs) have been investigated previously for beams-eye view (BEV) applications such as tumor tracking but are limited by low contrast-to-noise ratio and detective quantum efficiency. A novel multilayer imager (MLI), consisting of four stacked flat-panels was used to measure improvements in fiducial tracking during liver stereotactic body radiation therapy (SBRT) procedures compared to a single layer EPID.Methods.The prototype MLI was installed on a clinical TrueBeam linac in place of the conventional DMI single-layer EPID. The panel was extended during volumetric modulated arc therapy SBRT treatments in order to passively acquire data during therapy. Images were acquired for six patients receiving SBRT to liver metastases over two fractions each, one with the MLI using all 4 layers and one with the MLI using the top layer only, representing a standard EPID. The acquired frames were processed by a previously published tracking algorithm modified to identify implanted radiopaque fiducials. Truth data was determined using respiratory traces combined with partial manual tracking. Results for 4- and 1-layer mode were compared against truth data for tracking accuracy and efficiency. Tracking and noise improvements as a function of gantry angle were determined.Results. Tracking efficiency with 4-layers improved to 82.8
KW  - EPID (Other)
KW  - beams eye view (Other)
KW  - tumor tracking (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:34233309
DO  - DOI:10.1088/1361-6560/ac1246
UR  - https://inrepo02.dkfz.de/record/170001
ER  -