RITM: a mini γ camera for pre and per-operative radio guided cancer surgery evaluation for bone tumor localization in theater blocks

The authors have developed a multi-functional portable γ-radio-imager (RITM) based on a position sensitive photo-multiplier tube (PSPMT) in order to evaluate the potential of such a mini γ-camera concept in radio-pharmacology and nuclear medicine. The authors report here an evaluation of their RITM device for bone surgery. It concerns localization of the Osteoid Osteoma (benign bone tumor) performed in the theater block before skin incision and during the surgical lesion extraction. In the over 13 cases the authors studied, the diagnosis furnished by RITM was always confirmed by post-operation anatomopathological analysis. This shows how RITM can be used as an additional indicator to monitor the operation. Following RITM experience, the authors are developing a new small field of view γ-per-operative compact imager (POCI) with submillimeter spatial resolution performance. It consists of a high resolution collimator and a YAP:Ce crystal assembly coupled to an intensified position sensitive diode (IPSD). This hand-held imaging probe is first dedicated to intra-operative monitoring for thyroid tumor and neuroblastoma removal. Characteristics of the POCI device and preliminary results are briefly presented