Pre-therapeutic dosimetry and biodistribution of 86Y-DOTA-Phe1-Tyr3-octreotide versus 111In-pentetreotide in patients with advanced neuroendocrine tumours.
OBJECTIVE
For the internal radiotherapy of neuroendocrine tumours, the somatostatin analogue DOTATOC labelled with 90Y is frequently used [90Y-DOTA-Phe1-Tyr3)-octreotide (SMT487-OctreoTher)]. Radiation exposure to the kidneys is critical in this therapy as it may result in renal failure. The aim of this study was to compare cumulative organ and tumour doses based upon dosimetric data acquired with the chemically identical 86Y-DOTA-Phe1-Tyr3-octreotide (considered as the gold standard) and the commercially available 111In-pentetreotide.


METHODS
The cumulative organ and tumour doses for the therapeutic administration of 13.32 GBq 90Y-DOTA-Phe1-Tyr3-octreotide (three cycles, each of 4.44 GBq) were estimated based on the MIRD concept (MIRDOSE 3.1 and IMEDOSE). Patients with a cumulative kidney dose exceeding 27 Gy had to be excluded from subsequent therapy with 90Y-DOTA-Phe1-Tyr3-octreotide, in accordance with the directives of the German radiation protection authorities.


RESULTS
The range of doses (mGy/MBq 90Y-DOTA-Phe1-Tyr3-octreotide) for kidneys, spleen, liver and tumour masses was 0.6-2.8, 1.5-4.2, 0.3-1.3 and 2.1-29.5 (86Y-DOTA-Phe1-Tyr3-octreotide), respectively, versus 1.3-3.0, 1.8-4.4, 0.2-0.8 and 1.4-19.7 (111In-pentetreotide), with wide inter-subject variability. Despite renal protection with amino acid infusions, estimated cumulative kidney doses in two patients exceeded 27 Gy.


CONCLUSIONS
Compared with 86Y-DOTA-Phe1-Tyr3-octreotide, dosimetry with 111In-pentetreotide overestimated doses to kidneys and spleen, whereas the radiation dose to the tumour-free liver was underestimated. However, both dosimetric approaches detected the two patients with an exceptionally high radiation burden to the kidneys that carried a potential risk of renal failure following radionuclide therapy.
Helisch
Andreas
A
Department of Nuclear Medicine, University of Mainz, Mainz, Germany. helisch@nuklear.klinik.uni-mainz.de
Förster
Gregor J
GJ
Reber
Helmut
H
Buchholz
Hans-Georg
HG
Arnold
Rudolf
R
Göke
Burkhard
B
Weber
Matthias M
MM
Wiedenmann
Bertram
B
Pauwels
Stanislas
S
Haus
Ulrike
U
Bouterfa
Hakim
H
Bartenstein
Peter
P
D001822:Body Burden; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000532:radiotherapy; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D009928:Organ Specificity; D011832:Radiation Injuries / Q000517:prevention & control; D011835:Radiation Protection / Q000379:methods; D011874:Radiometry / Q000379:methods*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012062:Relative Biological Effectiveness; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D014018:Tissue Distribution; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use
D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D013004:Somatostatin; C081788:pentetreotide; D015282:Octreotide; C106246:Edotreotide