Patient organ dose during multicycle radiation dosimetry in Lutetium −177 radionuclide therapy

Precise patient radiation dosimetry during theranostic procedures allows clinicians to tailor therapeutic procedures to each patient. Organ dose measurement aids in adjustment of the administered activity or number of treatment cycles to maximize tumor cell destruction while minimizing damage to healthy tissues. This study was aimed at quantifying patient organ doses during Lu-177 DOTATATE and Lu-177 PSMA theranostic procedures. Nine patients underwent Lu-177 radionuclide therapy, usually four cycles with 6–8 GBq administered activity per cycle. The typical dose is 7.5 GBq as a fixed activity. Using quantitative dosimetry, physicians can estimate the next dose cycle according to patient condition. The average dose per activity for critical organs were low, at 1.76, 1.96, 0.25, 0.5, and 2.43 mSv/MBq for the right kidney, left kidney, liver bladder, and spleen, respectively. The doses for the left and right kidneys, liver, urinary bladder, and spleen were lower than those in previously published studies. Wide variations were observed in patient organ doses for Lu-177 DOTATATE and Lu-177 PSMA procedures. Further studies are recommended to ensure organ safety during theransotic procedures, to minimize the radiogenic risks to healthy organs.