Feasibility of 90Y TOF PET-based dosimetry in liver metastasis therapy using SIR-Spheres.
OBJECTIVE
(90)Y-labelled compounds used in targeted radiotherapy are usually imaged with SPECT by recording the bremsstrahlung X-rays of the beta decay. The continuous shape of the X-ray spectrum induces the presence of a significant fraction of scatter rays in the acquisition energy window, reducing the accuracy of biodistribution and of dosimetry assessments.


METHODS
The aim of this paper is to use instead the low branch of e(-) e(+) pair production in the (90)Y decay. After administration of (90)Y-labelled SIR-Spheres by catheterization of both liver lobes, the activity distribution is obtained by (90)Y time-of-flight (TOF) PET imaging. The activity distribution is convolved with a dose irradiation kernel in order to derive the regional dosimetry distribution.


RESULTS
Evaluation on an anatomical phantom showed that the method provided an accurate dosimetry assessment. Preliminary results on a patient demonstrated a high-resolution absorbed dose distribution with a clear correlation with tumour response.


CONCLUSIONS
This supports the implementation of (90)Y PET in selective internal radiation therapy of the liver.
Lhommel
Renaud
R
Department of Nuclear Medicine, Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium.
van Elmbt
Larry
L
Goffette
Pierre
P
Van den Eynde
Marc
M
Jamar
François
F
Pauwels
Stanislas
S
Walrand
Stephan
S
D005240:Feasibility Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy* / Q000556:secondary; D008863:Microspheres; D008875:Middle Aged; D009362:Neoplasm Metastasis; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D013997:Time Factors; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics
D015021:Yttrium Radioisotopes