Can I Really Double the Dose and Scan in Half the Time?
Aim: Application of Compassionate ALARA (CALARA) dictates increasing the activity used in selected procedures so that Nuclear Imaging durations are substantially reduced for elderly, demented or infirm patients. During 6 months of CALARA use, was the projected 20% applicability in our target bone scan group achieved. Which multipliers were selected. Was the image quality equivalent. Was staff dose increased.
Methods: Pain, dementia, mobility and weight were combined to a score from 1-4. Activity was multiplied by a CALARA value from 1-3 which was assigned from a table of scores v/s age range by a nuclear physician or registrar. Imaging duration was reduced in proportion to multiplied activity. CALARA multipliers were tallied for the 6 month period as were the total number of bone scans. 20 CALARA and 20 normal scans were randomised and assessed by 2 experienced reporters. Staff doses were reviewed
Results: CALARA bone scan duration was typically 11 minutes whole body + 8 minutes SPECT. 34/472 (7%) bone scans were CALARA multiplied with 32 at 2X and 2 at 1.5X. CALARA image quality was rated equally diagnostic. No trend showing extra staff dose due to CALARA is discernible for technical or nursing staff.
Conclusion: Our experience demonstrates that one barrier to CALARA adoption is the challenge to years of radiation protection dogma. Change of practice occurs slowly as we are only about half way to the estimated full applicability, but the benefits are substantial for the institution, the physician, and most especially - the patient.