Personnel exposure in labelling and administration of 177Lu-DOTA-D-Phe1-Tyr3-octreotide

ObjectiveThe introduction of peptide receptor radionuclide therapy, mainly performed with 90Y and 177Lu-labelled somatostatin analogues, has widened the therapeutic horizon of nuclear medicine.The handling of 177Lu-labelled pharmaceuticals implies an increase of the personnel exposure and this aspect is evaluated in this paper, in comparison with personal exposure in 90Y manipulation. Materials and methodsPersonal dose measurements were performed during 26 177Lu-DOTATOC preparations by using a series of thin active layer LiF: Mg,Cu,P thermoluminescence dosimeters fixed at the operator’s fingertips to evaluate the skin equivalent dose and by means of direct reading dosimeters positioned at the chest to evaluate the personal effective dose. Individual protection devices, such as shielded aprons and anti-X gloves, were also used. ResultsThe 95th percentile of the skin equivalent dose distribution for 177Lu operations by using 0.20-mm anti-X gloves was 0.080 mSv/GBq for the chemist and 0.011 mSv/GBq for the physician, whereas the 75th percentile was 0.058 mSv/GBq for the chemist and 0.006 mSv/GBq for the physician. The use of the 0.25 mm Pb-equivalent anti-X apron halved the personal equivalent dose measured over the apron by a direct reading dosimeter. Skin doses were compared with 90Y-DOTATOC procedures: no relevant exposure reduction is observed for chemists, whereas doses are considerably lower during administration procedures performed by physicians. ConclusionIn this study, an evaluation of the skin equivalent doses during 177Lu-DOTATOC labelling and administration is presented. These data can be useful to assess the risk for workers in centres that are starting to implement PRRT using 177Lu. The use of appropriate protection devices and procedures allows the observance of International Commission for Radiological Protection dose limits for exposed workers.