Michael Ljungberg, PhD, professor
Department of Medical Radiation Physics, Clinical Sciences Lund, Lund University, Sweden
Peptide receptor radiotherapy (PRRT) using 177-Lu-DOTATATE is currently being given for treatment of neuroendocrine tumours. The most commonly applied protocol is four treatments separated by approximately 2-3 months. The dose limiting organs are the bone marrow and the kidneys. The bone marrow function is regularly monitored by clinical means. Kidneys are late responding and their reaction cannot be monitored close to therapy. Their tolerance in terms of absorbed dose or biologically effective dose (BED) have not yet been generally established but in Lund, our clinical protocol use BED limits of 27 Gy (Step 1) or 40 Gy (Step 2), depending on the presence of risk factors. Based on these limits the number of treatments is calculated for individual patient based on accurate dosimetry, with the hypothesis that this individualization will provide a better tumour response than fixed four treatments given to all patients.
These lectures will describe the methodology behind 177-Lu dosimetry and the headlines will be as follows.