[External therapy with radioactive urine: a pitfall during sceletal scintigraphy]

Area of Science:

• Nuclear Medicine
• Dermatology
• Rheumatology

Background:

• Psoriasis arthropathica (psoriatic arthritis) is a chronic inflammatory condition affecting joints and skin.
• Bone scintigraphy is a nuclear medicine imaging technique used to assess joint inflammation.

Observation:

• A patient with psoriatic arthritis presented for a two-phase bone scan.
• Extensive skin contamination on the extremities was observed in delayed imaging.

Findings:

• The contamination originated from the patient's self-administration of radioactive urine as an embrocation for psoriasis exanthema (skin lesions).
• This resulted in artifactual signals on the bone scan, potentially obscuring or mimicking true joint pathology.

Implications:

• Highlights the critical importance of patient history and awareness of self-administered treatments in interpreting nuclear medicine scans.
• Underscores the potential dangers of using unverified radioactive substances for therapeutic purposes.
• Emphasizes the need for clear patient education regarding the risks associated with experimental or non-standard treatments.