[en] The BNCT shall be applied for an explantated organ with metastases at the TRIGA reactor Mainz, Germany. After the treatment of the patient with 10B pharmaceutical the liver will be explanted, irradiated in the thermal column and then implantated again (autotransplantation). This was first successfully done in 12/2001 for a 48 years old male patient at the TRIGA reactor in Pavia. For a treatment with BNCT it is necessary to determine the total dose and partial radiation doses like the boron and gamma dose. Since several parts of the dose can not be measured, calculations are necessary. For this procedure the program Simulation Environment for Radiotherapy Applications (SERA) developed by INEEL, Idaho, U.S., can be applied, which allows an individual dosimetry for the patient. The SERA program consists of a manual and semi-automated geometric modeling of the treatment objects like the liver derived from MRI, CT or other medical imaging modalities. The dose for these geometric models is calculated with the INEEL radiation transport computer code and the dose contouring is also derived. The SERA program was adapted at MHH to calculate the radiation dose in the case of liver autotransplantation. Also, the technical characteristics and the physical environment of the thermal column were programmed for SERA. For the first reactor model the core of the MHH TRIGA reactor and the thermal column of the Mainz TRIGA reactor were used. The thermal column was modulated with layers of bismuth and lead to minimize the gamma dose. (author)