Assessing and improving cobalt-60 digital tomosynthesis image quality

Matthew B. Marsh; L. John Schreiner; Andrew T. Kerr

doi:10.1117/12.2043066

19 March 2014 Assessing and improving cobalt-60 digital tomosynthesis image quality

Matthew B. Marsh, L. John Schreiner, Andrew T. Kerr

Proceedings Volume 9033, Medical Imaging 2014: Physics of Medical Imaging; 90335V (2014) https://doi.org/10.1117/12.2043066
Event: SPIE Medical Imaging, 2014, San Diego, California, United States

Abstract

Image guidance capability is an important feature of modern radiotherapy linacs, and future cobalt-60 units will be expected to have similar capabilities. Imaging with the treatment beam is an appealing option, for reasons of simplicity and cost, but the dose needed to produce cone beam CT (CBCT) images in a Co-60 treatment beam is too high for this modality to be clinically useful. Digital tomosynthesis (DT) offers a quasi-3D image, of sufficient quality to identify bony anatomy or fiducial markers, while delivering a much lower dose than CBCT. A series of experiments were conducted on a prototype Co-60 cone beam imaging system to quantify the resolution, selectivity, geometric accuracy and contrast sensitivity of Co-60 DT. Although the resolution is severely limited by the penumbra cast by the ~2 cm diameter source, it is possible to identify high contrast objects on the order of 1 mm in width, and bony anatomy in anthropomorphic phantoms is clearly recognizable. Low contrast sensitivity down to electron density differences of 3% is obtained, for uniform features of similar thickness. The conventional shift-and-add reconstruction algorithm was compared to several variants of the Feldkamp-Davis-Kress filtered backprojection algorithm result. The Co-60 DT images were obtained with a total dose of 5 to 15 cGy each. We conclude that Co-60 radiotherapy units upgraded for modern conformal therapy could also incorporate imaging using filtered backprojection DT in the treatment beam. DT is a versatile and promising modality that would be well suited to image guidance requirements.

Citation Download Citation

Matthew B. Marsh, L. John Schreiner, and Andrew T. Kerr "Assessing and improving cobalt-60 digital tomosynthesis image quality", Proc. SPIE 9033, Medical Imaging 2014: Physics of Medical Imaging, 90335V (19 March 2014); https://doi.org/10.1117/12.2043066

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
6 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Imaging systems

Point spread functions

Distortion

Image quality

Deconvolution

Computed tomography

Radiotherapy

Show All Keywords

Keywords/Phrases

Search In:

Publication Years