Radioimaging of various human tumours by means of somatostatin analogues an
d vasoactive intestinal peptide has been introduced into clinical practice
in recent years. The finding that human tumours express various subtypes of
somatostatin receptors has led to the development and characterization of
a navel peptide tracer termed MAURITIUS. MAURITIUS identifies a broad range
of somatostatin receptors with high binding affinity, and somatostatin rec
eptor 1 with low binding affinity. In order to evaluate patients for tumour
radiotherapy with Y-90-MAURITIUS, tumour dose calculation is performed wit
h In-111-MAURITIUS [In-111-DOTA-lanreotide]. Treatment is initiated in pati
ents presenting a tumour uptake of greater than or equal to 10 Gy/GBq (i.e.
, standard dose for 1 treatment cycle with Y-90-MAURITIUS). In 25 patients
with advanced cancer refractory to conventional antineoplastic treatment In
-111-MAURITIUS (similar to 150 MBq; 10 nmol/patient), scintigraphy and dosi
metry was performed Dosimetry data were calculated based on scintigraphic r
esults as well as urine, faeces and blood data. In all patients, at least o
ne tumour site was visualized during the initial few minutes of application
. Additional tumour sites not seen on conventional imaging (computerized to
mography, magnetic resonance imaging bone scan) could be detected in 6 pati
ents with carcinoids, one patient with prostate cancer and one patient with
lymphoma. Liver metastases were visualized in all patients with gastrointe
stinal cancers, while the primary tumour was not detected in 2 patients wit
h pancreatic, and in I patient wish rectal, cancel: The calculated radiatio
n dose for tumours and/or metastases ranged between 3-60 Gy/GBq for Y-90-MA
URITIUS. MAURITIUS is a universal receptor ligand for a large variety of di
fferent human tumours, and is suitable for treatment when labelled with Y-9
0.