Bone mineral density is an important measurement to detect osteoporosis.

The goal of this clinical trial is to compare bone mineral density measurements in CT examinations and DXA scans. The main question it aims to answer is:

• How good is the measurement of bone mineral density in the new photon-counting CT in comparison to DXA
• How can we optimize the CT scan for bone mineral density

Participants will undergo:

• Clinically indicated CT scan on day of inclusion
• Study related DXA scan on a separate appointment

Inclusion Criteria:

• Informed Consent signed by the subject
• Referral to a regular clinically indicated CT examination covering the lumbar area (e.g., Abdomen, Thorax + Abdomen, Neck + Thorax +Abdomen)
• Informed written and oral consent (interpreter present in case of foreign language patients)
• No contraindication to the clinically indicated CT examination

Exclusion Criteria:

• Patients < 18 years
• Pregnant women
• Vulnerable subjects
• Contraindications to the clinically indicated CT scan
• Multiple Myeloma
• Diffuse bone metastasis
• Fixateur interne in the lumbar spine
• Kyphoplasty in the lumbar spine
• Enterally administrated contrast agent
• Obtaining informed consent is not possible
• Withdrawal of consent orally or in writing
• Inability to follow the procedures of the investigation, e.g., due to language problems, psychological disorders, dementia, etc. of the subject
• Immobility (patients confined to a wheelchair or to bed)