Hybrid positron emission tomography/computed tomography (PET/CT) has now become available to detect tumors in patients with multiple myeloma. The radioactive glucose 18F-fluorodeoxyglucose (FDG) is the most widely used tracer but findings suggest that PET/CT reveal more lesions when using FCH.

In this study, FDG is compared with a more recent metabolic tracer, 18F-fluorocholine (FCH), for the detection of multiple myeloma lesions at time of initial extension assessment.

The principal objective of this sudy is to compare the number of suspected hypermetabolic foci of myeloma detected by 18F-fluorocholine PET and by 18F-fluorodeoxyglucose PET during the initial extension assessment.

Inclusion Criteria:

• Patient with initial diagnosis of multiple myeloma has just been established
• Therapeutic indication and eligible for a HSC autograft (if the HSC autograft could not be performed, the patient will still be retained in the study).
• Status ECOG 0, 1 or 2
• Age ≥ 18 and < 75 ans years
• Effective contraception for women
• Informed consent signed
• Patient able to lie flat for 30 minutes
• Patient affiliated to a social security scheme

Exclusion Criteria:

• Patient diagnosed with a diagnosis of MGUS (Monoclonal Gammapathy of Undetermined Significance = monoclonal gammopathy of undetermined significance), indolent myeloma ("smoldering myeloma"), non-secreting myeloma or recurrent myeloma,
• Patient already under treatment for myeloma.
• Patient not eligible for intensive treatment followed by a HSC autograft.
• Patient with concomitant neoplasia
• Patient with a history of hematological or solid neoplasia, except if it is a basal cell carcinoma of the skin or an adenocarcinoma in situ of the uterine cervix.
• Patient with a history of sarcoidosis
• Uncontrolled diabetes.
• Patient treated with long-term corticosteroids
• Patient being treated with hematopoietic growth factors
• Patient in sepsis.
• Claustrophobic patient.
• Refusal of patient consent.
• Pregnant or lactating woman.
• Women of childbearing potential without effective contraception.
• Person deprived of liberty or under guardianship
• Impossibility to submit to the medical follow-up of the trial for geographic, social or psychological reasons.
• History of allergic reaction attributed to 18F-fluorodeoxyglucose or to 18F-fluorocholine.