The establishment of national diagnostic reference levels for adult SPECT-CT in Saudi Arabia.

This study aims to introduce national diagnostic reference levels (NDRLs) for adult hybrid single photon emission computed tomography (SPECT-CT) in nuclear medicine (NM) departments in the Kingdom of Saudi Arabia. The administered activity (AA) of radiopharmaceuticals, volume-weighted computed tomography dose index (CTDI) and dose length product (DLP) for ten hybrid SPECT/CT examinations were collected and analysed for one year. The median of AA, CTDIand DLP for each dose quantity was derived and the suggested national DRLs were determined based on the 75percentile for all identified SPECT-CT examinations.