Study of the detective quantum efficiency for the kinestatic charge detector as a megavoltage imaging device

Sanjiv S. Samant; Arun Gopal; Frank A. DiBianca

doi:10.1117/12.482402

5 June 2003 Study of the detective quantum efficiency for the kinestatic charge detector as a megavoltage imaging device

Sanjiv S. Samant, Arun Gopal, Frank A. DiBianca

Author Affiliations +

Proceedings Volume 5030, Medical Imaging 2003: Physics of Medical Imaging; (2003) https://doi.org/10.1117/12.482402
Event: Medical Imaging 2003, 2003, San Diego, California, United States

Abstract

Megavoltage x-ray imaging suffers from relatively poor contrast and spatial resolution compared to diagnostic kilovoltage x-ray imaging due to the dominant Compton scattering in the former. Recently available amorphous silicon/selenium based flat-panel imagers overcome many of the limitations of poor contrast and spatial resolution that affect conventional video based electronic portal imaging devices (EPIDs). An alternative technology is presented here: kinestatic charge detection (KCD). The KCD uses a slot photon beam, high-pressure gas (xenon, 100 atm) and a multi-ion rectangular chamber in scanning mode. An electric field is used to regulate the cation drift velocity. By matching the scanning speed with that of the cation drift, the cations remain static in the object frame of reference, allowing temporal integration of the signal. KCD imaging is characterized by reduced scatter and a high signal-to-noise ratio. Measurements and Monte Carlo simulations of modulation transfer function (MTF), noise power spectrum (NPS) and the detective quantum efficiency (DQE) of a prototype small field of view KCD detector (384 channels, 0.5 mm spacing) were carried out. Measurements yield DQE[0]=0.19 and DQE[0.5cy/mm]=0.01. KCD imaging is compared to film and commercial EPID systems using phantoms, with the KCD requiring an extremely low dose (0.1 cGy) per image. A proposed cylindrical chamber design with a higher ion-collection depth is expected to further improve image quality (DQE[0]>0.25).

Citation Download Citation

Sanjiv S. Samant, Arun Gopal, and Frank A. DiBianca "Study of the detective quantum efficiency for the kinestatic charge detector as a megavoltage imaging device", Proc. SPIE 5030, Medical Imaging 2003: Physics of Medical Imaging, (5 June 2003); https://doi.org/10.1117/12.482402

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