A PC-based DICOM compatible PACS environment suitable for CT, MRI and 3D-US in radiotherapy

Stefan Wachter^{a b}, Thomas Lorang ^c, Manfred Gengler ^c, Natascha Gerstner ^a, Johann Moitzi ^a, Friedrich Vorbeck ^b, Alfred Kratochwil ^a, Ernst Schuster ^c, Richard Pötter ^a

(a)   Dep. of Radiotherapy and Radiobiology, (b) Dep. of Radiology, (c) Inst. of Medical Computer Sciences,

University Hospital Vienna, Austria.

Objective

Integration of a PC-based DICOM3 data set archiving, evaluation and communication system for sectional images into clinical use under prediction of DICOM3-standard and the fit to existing network architecture (Ethernet, TCP/IP-protocol, client-server environment, Windows 95/NT). Each of the integrated imaging modalities (CT, MRI, US) has its specific advantages and disadvantages for diagnostic purposes. Especially the synergistic comparison of multiple modalities offers new possibilities to compensate the restrictions of each single modality for terms of target definition.

System Description

A system for structured DICOM3 data set reception, conversion to different file types, central archiving and redistribution via a computerised network, suitable for CT (TCT-900Sâ, Toshiba), MRI (Magnetom Open Vivaâ, Siemens) and US (Combison 530Dâ, Kretztechnik) from different vendors has been installed in 1997. The archive system consists of a CD-ROM-Jukebox (70 Gbyte storage capacity), a SQL-database, a DICOM server and  software demons for conversion and hierarchical data management (patient, study, series, image).We added a self-developed software tool (written in C++) for merging single slice DICOM3-files into volume and video files. The size of  these merged data set is not limited (> 100 single images). This tool allows to create multiplanar reconstructions in any arbitrary angle, surface rendering and digital reconstructed radiographs (DRR´s) and muliple kinds of  free-hand as well as segmentation result overlays. Data sets from different modalities are correlated (by indicating a common coordinate origin and scaling factors) thus allowing fusion of either slice views, surface views, volume views and overlays. Virtual endoscopy is a future topic.

Results

We will show in detail by examples that this integrated system enables:

(I)              data exchange with other computer-controlled components (e.g. verification system);

(II)            separation of different steps of treatment planning, e.g. contouring of volumes of interest, from dedicated planning workstations to low-end personal computers;

(III)          comparisons of different data sets and volumetric measurements for estimation of tumor extent and treatment response.

(IV)         overlaying of  e.g. tumor contours extracted from MR into CT data sets 

First (pre-)clinical evaluations of cervical carcinoma and prostate carcinoma in views reconstructed from multiple modalities showed significant benefits  compared to evaluations restricted to single modalities for purposes of target definition.

Corresponding Author:

Oral presentation at EuroPACS'98, Barcelona, Spain