This study is a phase I clinical trial aimed to determine the recommended dose of 99mTc-NTP 15-5 to obtain the best tracer joints contrast on images without any toxicity.

Inclusion Criteria:

Inclusion criteria specific to group 1:

- Patient with painful unilateral osteoarthritis of the knee as femorotibial pattern defined by a radiographic score of 0/1 from Kellgren / Lawrence and an average WOMAC score> or equal to 4 and by minor disorders at MRI (MOCART 2.0 score> 70).

Inclusion criteria specific to group 2:

• Patient with non-metastatic breast cancer, hormone receptor positive, HER2 negative, with indication for adjuvant therapy with aromatase inhibitor; treatment not yet started.
• Age <60 years

Common inclusion criteria:

• Patient with at least 31 healthy joints (based on clinical assessment)
• signed written informed consent.
• Affiliation to a health insurance scheme.
• For women of childbearing age : negative serum pregnancy test at inclusion (less than 7 days prior injection of 99mTc-NTP 15-5).
• Willing and able to comply with study visits, treatment, exams and the protocol.

Exclusion Criteria:

• Patients <18 years of age.
• Pregnant or lactating patient.
• BMI> 30
• History of known allergy to excipients contained in the solution of 99mTc-NTP 15-5
• Chronic inflammatory rheumatism (rheumatoid arthritis, spondyloarthropathy, psoriatic arthritis, etc.) diffuse arthritis (at least 3 joints affected), autoimmune connectivitis, fibromyalgia.
• Known chronic joint pathology: osteoarthritis affecting at least 3 joints, autoimmune disease, inflammatory rheumatism (except unilateral knee arthritis).
• Persons deprived of their liberty, under guardianship / curatorship, or safeguard of justice.
• Treatment with NSAIDs or cessation of less than 48 h.
• Inability to comply with medical requirement / follow-up of the trial for geographic, family, social or psychological reasons. These conditions should be discussed with the patient before registration in the study.