[The role of high-energy imaging in a radiotherapy service and its incorporation in a network].
To directly compare the clinical efficacy of electronic to film portal images and the advantages of comparing directly on the monitor the simulation image and the portal image.


METHODS
This study was designed to compare clinical efficacy of electronic to film portal images acquired using a liquid matrix ion-chamber electronic portal imaging device (EPID) and a conventional film system. Two radiation oncologists served as observers and evaluated a total of 30 sets of images for three different treatment sites: lung, pelvis, and head/neck. Each set of images included a simulation image, a portal film, a video paper print of electronic portal images, and a video prints of electronic portal images. Four to six anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and to rate the ease of making the pertinent verification decision in the corresponding electronic and film portal images with the aid of the simulation image. The time needed to obtain and analyse a conventional portal image and an EPID would be analysed for the radiotherapist and the medical technicians.


RESULTS
Ratings for the visibility of landmarks and for the verification decision of treatment ports were similar for electronic and film images for most landmarks. However, vertebral bodies and several landmarks in the pelvis such as the acetabulum and pubic symphysis were more visible in the electronic portal images than in the portal film images. For the medical technicians, the EPID is more comfortable, and they do not need to develop any images.


CONCLUSIONS
The visibility of landmarks in electronic portal images is comparable to that in film portal images. Verification of treatment ports based only on electronic portal images acquired using an electronic portal imaging device is generally achievable. Thus the integration of the EPID and simulation image in a network provides more flexibility in the daily work of a medical radiotherapy team.
Pradier
O
O
Klinik und poliklinik für trahlentherapie und radioonkologie, universität Göttingen, Robert Koch Str. 40, D 37075 Göttingen, Allemagne.
Hille
A
A
Schmidberger
H
H
Hess
C F
CF
D003952:Diagnostic Imaging / Q000295:instrumentation* / Q000592:standards; D004867:Equipment Design; D005602:France; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007255:Information Services; D010315:Particle Accelerators / Q000295:instrumentation* / Q000592:standards; D011786:Quality Control; D011882:Radiotherapy, High-Energy / Q000295:instrumentation* / Q000592:standards