Contribution of the VERITON-CT Camera in Prostate Bone Radiostereotaxy

Stereotactic radiotherapy enables bone metastases to be treated with highly precise irradiation beams, enabling small targets to be irradiated. Planning requires the use of cross-sectional imaging such as computed tomography (CT) or magnetic resonance imaging (MRI). Bone scintigraphy with Tc99m-labelled biphosphonates (T1/2=6h) is indicated in the extension assessment of prostate cancers. Thanks to the advent of single-photon emission computed tomography (SPECT) based on CZT detectors; whole-body SPECT is now compatible with clinical constraints. We propose to study the value of using whole-body SPECT for planning stereotactic radiotherapy of metastatic prostate cancer. This is a prospective, single-center, non-randomized study involving 30 patients. Patients will benefit from routine examinations (CT scan, MRI) including a bone SPECT/CT in treatment position performed on the VERITON-CT (Spectrum Dynamics, Haifa, Israel). Planning based on whole-body SPECT images will be carried out remotely from the patient's point of care. The examination will be interpreted by the nuclear physician, and planning will be based on the dosimetric CT scanner, as in standard management. Virtual replanning will be carried out at distance from treatment, incorporating SPECT imaging. Treatment plans with and without SPECT will be compared quantitatively and qualitatively. The feasibility of SPECT imaging in the treatment position will be assessed, enabling lesion location imaging and dosimetric scanning to be performed in a single examination. All therapeutic management and clinical follow-up will be carried out as part of routine care.

Inclusion Criteria: * Age ≥ 18 years, * Good general health WHO ≤ 1 * Informed and signed consent prior to any specific study procedure. * Patient affiliated to the social security system * Bone metastases from prostate cancer * Indication for bone stereotactic radiotherapy Exclusion Criteria: * Presence of active cancer in the previous three years * Protected adults (under guardianship or curatorship) * Unable to undergo medical monitoring for geographical, social or psychological reasons * Unable to decubitus (orthopnea, etc.), * Hypersensitivity to HDP or to one of the excipients of the radiopharmaceutical. * History of radiotherapy of the volume to be treated by stereotaxy.