Section: New Results

Biological Image Analysis

Pre-clinical molecular imaging: reconstruction of tumors in rodents with SPECT imaging

Participants : Marine Breuilly [Correspondant] , Grégoire Malandain, Nicholas Ayache, Jacques Darcourt [CAL] , Philippe Franken [CAL] , Thierry Pourcher [CEA] .

This work is jointly conducted with the Transporter in Imagery and Oncologic Radiotherapy team (TIRO, CEA-CAL-UNSA) located in Nice.

The coupled CT and SPECT device allows to image both the anatomy (with the CT) and physiology information targeted by a dedicated radio-pharmaceutical tracer (here the tumors, with the SPECT). However, tumor quantification is impaired by the respiratory motion that induces an artifical enlargement of the moving structures. We propose then to select all the motion-less phases from a 4D SPECT images to reconstruct a motion-free 3D image. In addition, we also propose to correct for the heterogeneity of the respiratory cycles by re-tagging the SPECT raw data.

The resulting 3D motionless gated image shows improvment of volume accuracy compared to the non gated SPECT image; and noise reduction compared to the 4D SPECT image (see Figure 5 )

Figure 5. Coronal slices of fused SPECT and CT images from a NOD-SCID mouse (data acquired with GE eXplore speCZT CT 120): central hot spots reveal intraperitoneal metastasis from adenocarcinoma of the colon (PROb-mNIS). Left to right: non gated, phase at end of expiration, phase at end of inhalation, and motionless gated.