Minimum Detectable Activity
Pronunciation: M-D-A
Also written as: MDA — Minimum Detectable Activity
Lowest activity level that can be reliably detected by a nuclear medicine imaging system.
Full Definition
Minimum Detectable Activity represents the smallest amount of radioactive material that can be reliably distinguished from background noise in nuclear medicine imaging systems. MDA is influenced by factors including detector sensitivity, acquisition time, patient attenuation, and background activity levels. Understanding MDA is crucial for interpreting negative studies, determining appropriate imaging protocols, and assessing the clinical significance of subtle findings in oncologic nuclear medicine studies.
Usage
Usage note: Report MDA values with appropriate radioactivity units (typically MBq or mCi).
In Context
- "The lesion activity was below the system's MDA, precluding reliable quantification." — Nuclear medicine report
- "Protocol optimization reduced the MDA to improve detection of small metastases." — Technical quality assurance