AIMS: Fractionated (177)Lu-DOTA-octreotate therapy has been reported to be an effective treatment option for patients with generalized neuroendocrine tumors. In our clinic, full individual dosimetry is performed during the first therapy cycle, while dosimetry at later cycles is based on the 24 h uptake measurement assuming an unchanged effective half-life. Our aim was to evaluate this assumption and the variation in the 24 h uptake during therapy. PATIENTS: Thirty patients, 13 women and 17 men, were included in the study. METHODS: During the first therapy cycle the (177)Lu-concentration was measured with SPECT/CT over the abdomen at 24 h, 96 h and 168 h after infusion. The effective half-life was determined for the kidneys, liver and spleen. The procedure was repeated at cycle 4 or 5. RESULTS: The median ratio between the effective half-lives of the latter and the first cycle was 0.97 and 1.01 for the right and left kidney, with a range of 0.89-1.01 (1st-3rd quartile) and 0.93-1.05, respectively. DISCUSSION: The mean value of the ratios was slightly lower than one, indicating a tendency towards increased activity elimination during therapy. In individual patients, significant changes were found for all organs, often when a large tumor burden reduction occurred during treatment. Possible contributing factors appeared to be larger amounts of non-tumor bound tracer, improved organ function (kidneys), decrease of vessel obstruction (spleen), less scatter from large tumors and reduction of small metastases (liver and spleen). CONCLUSION: With most patients it is safe to estimate absorbed doses to kidneys, liver and spleen from 24 h activity concentration assuming an unchanged effective half-life during therapy. Patients with risk factors for kidney dysfunction need to be monitored in more detail. Simplified dosimetry based on the assumption of unchanged effective half-life can function as guidance to the number of therapy cycles an individual patient can tolerate.
AIMS: Fractionated (177)Lu-DOTA-octreotate therapy has been reported to be an effective treatment option for patients with generalized neuroendocrine tumors. In our clinic, full individual dosimetry is performed during the first therapy cycle, while dosimetry at later cycles is based on the 24 h uptake measurement assuming an unchanged effective half-life. Our aim was to evaluate this assumption and the variation in the 24 h uptake during therapy. PATIENTS: Thirty patients, 13 women and 17 men, were included in the study. METHODS: During the first therapy cycle the (177)Lu-concentration was measured with SPECT/CT over the abdomen at 24 h, 96 h and 168 h after infusion. The effective half-life was determined for the kidneys, liver and spleen. The procedure was repeated at cycle 4 or 5. RESULTS: The median ratio between the effective half-lives of the latter and the first cycle was 0.97 and 1.01 for the right and left kidney, with a range of 0.89-1.01 (1st-3rd quartile) and 0.93-1.05, respectively. DISCUSSION: The mean value of the ratios was slightly lower than one, indicating a tendency towards increased activity elimination during therapy. In individual patients, significant changes were found for all organs, often when a large tumor burden reduction occurred during treatment. Possible contributing factors appeared to be larger amounts of non-tumor bound tracer, improved organ function (kidneys), decrease of vessel obstruction (spleen), less scatter from large tumors and reduction of small metastases (liver and spleen). CONCLUSION: With most patients it is safe to estimate absorbed doses to kidneys, liver and spleen from 24 h activity concentration assuming an unchanged effective half-life during therapy. Patients with risk factors for kidney dysfunction need to be monitored in more detail. Simplified dosimetry based on the assumption of unchanged effective half-life can function as guidance to the number of therapy cycles an individual patient can tolerate.
Authors: Andreas Delker; Wolfgang Peter Fendler; Clemens Kratochwil; Anika Brunegraf; Astrid Gosewisch; Franz Josef Gildehaus; Stefan Tritschler; Christian Georg Stief; Klaus Kopka; Uwe Haberkorn; Peter Bartenstein; Guido Böning Journal: Eur J Nucl Med Mol Imaging Date: 2015-08-29 Impact factor: 9.236
Authors: Sabine Maurer; Peter Herhaus; Romina Lippenmeyer; Heribert Hänscheid; Malte Kircher; Andreas Schirbel; H Carlo Maurer; Andreas K Buck; Hans-Jürgen Wester; Hermann Einsele; Götz-Ulrich Grigoleit; Ulrich Keller; Constantin Lapa Journal: J Nucl Med Date: 2019-03-08 Impact factor: 10.057
Authors: Johanna Svensson; Gertrud Berg; Bo Wängberg; Maria Larsson; Eva Forssell-Aronsson; Peter Bernhardt Journal: Eur J Nucl Med Mol Imaging Date: 2015-02-06 Impact factor: 9.236
Authors: Rudolf A Werner; Seval Beykan; Takahiro Higuchi; Katharina Lückerath; Alexander Weich; Michael Scheurlen; Christina Bluemel; Ken Herrmann; Andreas K Buck; Michael Lassmann; Constantin Lapa; Heribert Hänscheid Journal: Oncotarget Date: 2016-07-05