Speaker
Prof.
Francesco Scopinaro
(Univ. Roma "La Sapienza" - Italy)
Description
Aim. New radiopharmaceuticals are growing attention for cancer diagnosis and
therapy. This work deals with the use of an updated High resolution (HR) camera for
small animal imaging.
Matherials and Methods. We studied three radiopharmaceuticals: two antibodies
(MoAb) and one peptide (P) labelled with 99mTechnetium in 20 rodents. Balb/c nude
mice xenografted with cancer cells or T- lymphocytes (T-LY) were injected with 3.7
MBq of MoAbs. A series of three mice were xenografted respectively with 5, 10 and
20 x 106 T-LY. 99mTchmetium were studied with Anger camera (AC) fitted with
parallel hole, high resolution, low energy collimator and our new HR device. Five
rats, weighting 250g each, were tested with peptide and images were acquired only
with HR SPECT. Our HR camera (Li-Tech, Italy) is based on multi-crystal and
Hamamatsu position sensitive phototubes technique (PSPMT) with spatial resolution
of 2 mm. It was equipped with a mechanical arm to scan the entire body of rodents
or to perform SPECT. HR camera, collimators and crystal-collimator-PSPMT matching
are covered by 5 US and EU patents.
99mTc-Mo-Abs were directed against a cancer specific protein (MoAb 1) and T
lymphocytes activated versus ulcerative cholitis (MoAb 2) and were studied with
whole body planar scan 6, 12 and 24 h after injection. The 99mTc-P was studied with
SPECT 180°, 36 views, from 1 to 3 h after injection. SPECT images were
reconstructed with a rotation-based version of OSEM.
Results. Whole body scan of nude mice required 3 ±0.5 min at 6h, 10± 3 min at 12
and 20±9 min at 24h when acquired with the 1 inch2 FOV HR camera. These times were
not significantly different with Anger camera. The 4 inch2 FOV HR camera performed
scans respectively in 1± 0.2 (P<0.01), 4± 2 ( P< 0.01) and 9± 5 (P<0.01) min.
SPECTs of rat brain were acquired in 10±3 min.
Both Anger camera and HR cameras imaged the xenografted tumours. However necrotic
zones inside tumours were shown only by HR cameras. All X of T-LY were shown by HR
cameras with direct relationship among number of xenografted cells and
Target/Background ratio, whereas Anger camera showed only xenografted of 20x106 T-
LY. HR SPECT showed Amygdale, Hippocampus, and dorso-lateral nuclei of thalamus in
rat brain. All these sub-cerebral structures of rat were measured at autopsy as
slightly larger of 2 mm on mayor axis.
Conclusion. HR small animal imaging is useful in the study of new
radiopharmaceuticals. Our device is faster than Anger camera and is able to show
uptake sites missed by Anger camera
Author
Prof.
Francesco Scopinaro
(Univ. Roma "La Sapienza" - Italy)
Co-authors
Dr
Alberto Signore
(University "La Sapienza")
Dr
Alessandro Soluri
(Institute of Biomedical engeenering (ISIB) CNR)
Dr
Alexandra Varvarigou
(National research Centre "Demokritos)
Dr
Armando bartolazzi
(Cancer Center Karolinska Inst.)
Dr
Carlo Trotta
(Institute of Biomedical engeenering (ISIB) CNR)
Dr
D'alessandria Calogero
(University "La Sapienza")
Dr
E Paschali
(National research Centre "Demokritos)
Dr
Giampaolo Di Santo
(University "La Sapienza")
Dr
Maria Grazia Parisella
(University "La Sapienza")
Dr
Roberto Massari
(Institute of Biomedical engeenering (ISIB) CNR)