4D cone beam CT phase sorting using high frequency optical surface measurement during image guided radiotherapy

G. J. Price; T. E. Marchant; J. M. Parkhurst; P. J. Sharrock; G. A. Whitfield; C. J. Moore

doi:10.1117/12.877637

16 March 2011 4D cone beam CT phase sorting using high frequency optical surface measurement during image guided radiotherapy

G. J. Price, T. E. Marchant, J. M. Parkhurst, P. J. Sharrock, G. A. Whitfield, C. J. Moore

Author Affiliations +

Proceedings Volume 7961, Medical Imaging 2011: Physics of Medical Imaging; 79615S (2011) https://doi.org/10.1117/12.877637
Event: SPIE Medical Imaging, 2011, Lake Buena Vista (Orlando), Florida, United States

Abstract

In image guided radiotherapy (IGRT) two of the most promising recent developments are four dimensional cone beam CT (4D CBCT) and dynamic optical metrology of patient surfaces. 4D CBCT is now becoming commercially available and finds use in treatment planning and verification, and whilst optical monitoring is a young technology, its ability to measure during treatment delivery without dose consequences has led to its uptake in many institutes. In this paper, we demonstrate the use of dynamic patient surfaces, simultaneously captured during CBCT acquisition using an optical sensor, to phase sort projection images for 4D CBCT volume reconstruction. The dual modality approach we describe means that in addition to 4D volumetric data, the system provides correlated wide field measurements of the patient's skin surface with high spatial and temporal resolution. As well as the value of such complementary data in verification and motion analysis studies, it introduces flexibility into the acquisition of the signal required for phase sorting. The specific technique used may be varied according to individual patient circumstances and the imaging target. We give details of three different methods of obtaining a suitable signal from the optical surfaces: simply following the motion of triangulation spots used to calibrate the surfaces' absolute height; monitoring the surface height in a single, arbitrarily selected, camera pixel; and tracking, in three dimensions, the movement of a surface feature. In addition to describing the system and methodology, we present initial results from a case study oesophageal cancer patient.

Citation Download Citation

G. J. Price, T. E. Marchant, J. M. Parkhurst, P. J. Sharrock, G. A. Whitfield, and C. J. Moore "4D cone beam CT phase sorting using high frequency optical surface measurement during image guided radiotherapy", Proc. SPIE 7961, Medical Imaging 2011: Physics of Medical Imaging, 79615S (16 March 2011); https://doi.org/10.1117/12.877637

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