Thermoluminescent dosimetry (TLD) in bladder and rectum during gynecological afterloading brachytherapy

In gynecological afterloading brachytherapy with moved radiation source the dose distribution around the applicator could be calculated exactly by computer tomogram. Control is possible by autoradiography with evaluation by film densitometry. Absolute measurements were performed in water or plexiglas phantoms. Because of the whole anatomical state the position of the applicator could differ from application to application. Therefore the dose of critical organs could be estimated in advance, but could not be calculated correctly. Flexible probes carrying some TL dosemeters were placed into bladder or rectum before radiotherapy. Opaque distance pieces within the probe allow to determine the position of the TL dosemeters. With the measured single doses of each fraction and the corresponding position analysis the radiation dose of critical organs could be estimated more accurately. (author)