[The use of contrast media for quality assurance in radiotherapy planning]

The target volume definition in radiation therapy was evidently improved by CT and MRI. Basis of treatment planning, however, remains the therapy simulator. Important instruments for adequate fluoroscopic treatment planning are contrast media that recently have been applied less out of legal and professional reasons. Aim of this work is to evaluate the possible benefit of contrast media applications.

In 1303 simulations between 1.1.1993 and 30.9.1993 105 times intravenous contrast media were applied, supplied by oral or endolymphatic contrast agents. It was studied if the previously intended plan had to be altered due to contrast media application.

In 17 out of 105 cases (16.2%) the target volume or the preplanned technique had to be altered after contrast media application. Main reason was the existence of anatomical variations especially in kidney and small bowel detected by use of contrast agents. So standard indications for contrast media applications were defined.

Contrast media are an important tool in treatment planning that should be orientated on diagnostical standards. Applications of contrast agents facilitate the detection of anatomical variations and the selection of the appropriate technique in order to shield sensitive tissues. The therapeutical and legal benefit outweigh potential hazards due to intolerances or professional obstacles.