TY - JOUR
T1 - Megavoltage imaging with a large-area, flat-panel, amorphous silicon imager
AU - Antonuk, Larry E.
AU - Yorkston, John
AU - Huang, Weidong
AU - Sandler, Howard
AU - Siewerdsen, Jeffrey H.
AU - El-Mohri, Youcef
N1 - Funding Information:
These considerations have led to the creation of a va- riety of electronic portal imaging devices (EPIDs). While the earliest development efforts date back to the late 1950s (29), the rate of progress accelerated considerably in the 1980s (15). As a result, a variety of portal imagers are sistance in the interpretation of the images, and John M. Boudry, B.S., for his valuable comments on the manuscript. They gratefully acknowledge the cooperation of their department’s radiation therapists in performing the patient imaging. This work is supported by Grant 2R01-CA51397 from the National Institutes of Health. Accepted for publication 5 July 1996.
PY - 1996/10/1
Y1 - 1996/10/1
N2 - Purpose: The creation of the first large-area, amorphous silicon megavoltage imager is reported. The imager is an engineering prototype built to serve as a stepping stone toward the creation of a future clinical prototype. The engineering prototype is described and various images demonstrating its properties are shown including the first reported patient image acquired with such an amorphous silicon imaging device. Specific limitations in the engineering prototype are reviewed and potential advantages of future, more optimized imagers of this type are presented. Methods and Materials: The imager is based on a two-dimensional, pixelated array containing amorphous silicon field-effect transistors and photodiode sensors which are deposited on a thin glass substrate. The array has a 512 x 560-pixel format and a pixel pitch of 450μm giving an imaging area of ~23 x 25 cm2. The array is used in conjunction with an overlying metal plate/phosphor screen converter as well as an electronic acquisition system. Images were acquired fluoroscopically using a megavoltage treatment machine. Results: Array and digitized film images of a variety of anthropomorphic phantoms and of a human subject are presented and compared. The information content of the array images generally appears to be at least as great as that of the digitized film images. Conclusion: Despite a variety of severe limitations in the engineering prototype, including many array defects, a relatively slow and noisy acquisition system, and the lack of a means to generate images in a radiographic manner, the prototype nevertheless generated clinically useful information. The general properties of these amorphous silicon arrays, along with the quality of the images provided by the engineering prototype, strongly suggest that such arrays could eventually form the basis of a new imaging technology for radiotherapy localization and verification. The development of a clinically useful prototype offering high- quality images, ultimately with an ~52 x 52-cm2 detection surface, is anticipated.
AB - Purpose: The creation of the first large-area, amorphous silicon megavoltage imager is reported. The imager is an engineering prototype built to serve as a stepping stone toward the creation of a future clinical prototype. The engineering prototype is described and various images demonstrating its properties are shown including the first reported patient image acquired with such an amorphous silicon imaging device. Specific limitations in the engineering prototype are reviewed and potential advantages of future, more optimized imagers of this type are presented. Methods and Materials: The imager is based on a two-dimensional, pixelated array containing amorphous silicon field-effect transistors and photodiode sensors which are deposited on a thin glass substrate. The array has a 512 x 560-pixel format and a pixel pitch of 450μm giving an imaging area of ~23 x 25 cm2. The array is used in conjunction with an overlying metal plate/phosphor screen converter as well as an electronic acquisition system. Images were acquired fluoroscopically using a megavoltage treatment machine. Results: Array and digitized film images of a variety of anthropomorphic phantoms and of a human subject are presented and compared. The information content of the array images generally appears to be at least as great as that of the digitized film images. Conclusion: Despite a variety of severe limitations in the engineering prototype, including many array defects, a relatively slow and noisy acquisition system, and the lack of a means to generate images in a radiographic manner, the prototype nevertheless generated clinically useful information. The general properties of these amorphous silicon arrays, along with the quality of the images provided by the engineering prototype, strongly suggest that such arrays could eventually form the basis of a new imaging technology for radiotherapy localization and verification. The development of a clinically useful prototype offering high- quality images, ultimately with an ~52 x 52-cm2 detection surface, is anticipated.
KW - Amorphous silicon array
KW - Digital imaging
KW - Flat-panel imager
KW - Megavoltage imaging
UR - https://www.scopus.com/pages/publications/0030272271
UR - https://www.scopus.com/pages/publications/0030272271#tab=citedBy
U2 - 10.1016/S0360-3016(96)00358-6
DO - 10.1016/S0360-3016(96)00358-6
M3 - Article
C2 - 8948351
AN - SCOPUS:0030272271
SN - 0360-3016
VL - 36
SP - 661
EP - 672
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 3
ER -