short arc digital tomosynthesis as an image enhancement step for detection and localization of...
DESCRIPTION
Image Enhancement using Short Arc DTS Example scenario: Gantry rotation during treatment e.g. RapidArc Use MV projections over last θ degrees to reconstruct a DTS image Targets that would otherwise be obscured by scatter noise and overlaying structures will be enhanced sufficiently for successful automatic trackingTRANSCRIPT
![Page 1: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/1.jpg)
Short Arc Digital Tomosynthesis as an Image Enhancement Step
for Detection and Localization of Implanted Markers
Margie Hunt, Pengpeng Zhang
Memorial Sloan-Kettering Cancer Center, New York NY
Hassan Mostafavi, Alexander Sloutsky, Andrew Jeung
Varian Medical Systems Inc., Palo Alto CA
![Page 2: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/2.jpg)
• Automatic detection of implanted radio-opaque markers can be challenging due to noise, scatter, and obfuscating structures
• Image enhancement by Short Arc Digital Tomosynthesis (DTS) – tomosynthesis reconstruction over a 3 – 5° arc – may enhance images to aid detection
• Enhancement can be quantified by matching to an image template and calculating the peak-to-sidelobe ratio (PSR) of the resulting match surface
Study Objectives
![Page 3: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/3.jpg)
Image Enhancement using Short Arc DTS
Example scenario: Gantry rotation during treatment e.g. RapidArc
Use MV projections over last θ degrees to reconstruct a DTS image
Targets that would otherwise be obscured by scatter noise and overlaying structures will be enhanced sufficiently for successful automatic tracking
![Page 4: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/4.jpg)
Results
Comparison of original MV images (left) to DTS-enhanced images (right). DTS-enhanced markers are easier to identify, and band artifacts due to linac are eliminated.
a
b
PSR = 5.812
c
PSR = 8.251
Template of markers generated from plan CT (a) matches with the DTS-enhanced image (c) with a higher PSR score than with the original MV projection (b).
![Page 5: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/5.jpg)
Gantry AnglePSR:
Template to original image
PSR:Template to
DTS-enhanced
image
21.3° 5.812 8.251
49.0° 3.007 5.666
81.0° 3.031 3.734
DTS enhancement results in a consistently higher peak-to-sidelobe ratio (PSR)
![Page 6: Short Arc Digital Tomosynthesis as an Image Enhancement Step for Detection and Localization of Implanted Markers Margie Hunt, Pengpeng Zhang Memorial Sloan-Kettering](https://reader034.vdocuments.site/reader034/viewer/2022051202/5a4d1b687f8b9ab0599b1857/html5/thumbnails/6.jpg)
Conclusions
• Short Arc DTS can enhance image sequences acquired during gantry rotation
• It shows promise in making detection and localization of markers more robust and accurate
• Template matching and use of peak-to-sidelobe ratio can quantify the improvement in detectability