This is a pilot, single-center, prospective, open-label clinical investigation of a medical device (ambulatory gamma camera " MoTI " (Mobile Therapy Imager)) for patients with hyperthyroidism (Graves' disease, toxic nodule and toxic multiheteronodular goiter) for whom 131I treatment is indicated.

Its aim is to assess the feasibility of using this ambulatory gamma camera (MoTI) in the clinic in this patient population.

20 patients will be included in the study.

Inclusion Criteria:

1. Age ≥ 18 years.
2. Patient with hyperthyroidism (Graves' disease, toxic nodular goiter (TNG) or toxic multi hetero nodular goiter (GMHNT)) relevant to an indication for 131I treatment.
3. Patient with no risk of iodine saturation.
4. Patient able to maintain a sitting position in an armchair for 10 minutes with chin raised and held by a "chin rest" with head in extension.
5. WHO index ≤ 1.
6. For non-menopausal patients, use of an effective contraceptive method at the start of the clinical investigation and throughout the clinical investigation, and a negative pregnancy test before administration of the tracer activity and the 131I therapeutic activity.
7. Patient signed informed consent prior to inclusion in the clinical investigation and prior to any specific procedure for the clinical investigation.
8. Patient affiliated to a social security scheme in France.

Exclusion Criteria:

1. Absence of clinical or biological hyperthyroidism.
2. Patient with a contraindication to 131I treatment.
3. Existence of one or more nodule(s) associated with hyperthyroidism at risk of malignancy according to EU-TIRADS and Bethesda criteria if cytopuncture performed.
4. Active orbithopathy associated with Graves' disease.
5. Contrast-enhanced examination performed within the two months prior to inclusion.
6. Use of iodised products for skin disinfection (Betadine) in the 4 weeks prior to inclusion.
7. Treatment with Amiodarone and derivatives in the 18 months prior to inclusion. (Ioduria test to rule out iodine saturation).
8. Pregnant or breast-feeding woman.
9. Patient planning pregnancy within 6 months of 131I treatment.
10. Any psychological, family, geographical or sociological condition that makes it impossible to comply with the medical monitoring and/or procedures set out in the clinical investigation protocol.
11. Any co-existing medical condition which, in the opinion of the investigator, could constitute a risk by participating in this study.
12. Patient who has forfeited his/her freedom by administrative or legal award or who is under legal protection (curatorship and guardianship, protection of justice).