Lu-177-PSMA-617 Prostate-Specific Membrane Antigen Inhibitor Therapy in Patients with Castration-Resistant Prostate Cancer: Stability, Bio-distribution and Dosimetry

• Published in: Molecular imaging and radionuclide therapy 2017-06, Vol.26 (2), p.62-68
• Main Authors: Kabasakal, Levent, Toklu, Türkay, Yeyin, Nami, Demirci, Emre, Abuqbeitah, Mohammad, Ocak, Meltem, Aygün, Aslan, Karayel, Emre, Pehlivanoğlu, Hüseyin, Alan Selçuk, Nalan
• Format: Article
• Language: English
• Subjects: Blood; Bone marrow; Cancer; Castration; Computation; Computed tomography; Dosimeters; Dosimetry; Economic conditions; Economic forecasts; Economic indicators; Excretion; Fractionation; Glands; Half-life; In vitro methods and tests; In vivo methods and tests; Kidneys; Lutetium; Mathematical analysis; Original; Patients; Pharmacology; Photon emission; Prostate cancer; Radiation; Radiation dosage; Radioactive half-life; Radioactivity; Radiochemical analysis; Single photon emission computed tomography; Stability; Statistical data; Therapy; Tıp; Urine
• ISSN: 2146-1414; 2147-1959
• DOI: 10.4274/mirt.08760

The aim of the study was to estimate the radiation-absorbed doses and to study the in vivo and in vitro stability as well as pharmacokinetic characteristics of lutetium-177 (Lu-177) prostate-specific membrane antigen (PSMA)-617. For this purpose, 7 patients who underwent Lu-177-PSMA therapy were included into the study. The injected Lu-177-PSMA-617 activity ranged from 3.6 to 7.4 GBq with a mean of 5.2±1.8 GBq. The stability of radiotracer in saline was calculated up to 48 h. The stability was also calculated in blood and urine samples. Post-therapeutic dosimetry was performed based on whole body and single photon emission computed tomography/computed tomography (SPECT/CT) scans on dual-headed SPECT/CT system. The radiochemical yield of Lu-177-PSMA-617 was >99%. It remained stable in saline up to 48 h. Analyses of the blood and urine samples showed a single radioactivity peak even at 24 hours after injection. Half-life of the distribution and elimination phases were calculated to be 0.16±0.09 and 10.8±2.5 hours, respectively. The mean excretion rate was 56.5±8.8% ranging from 41.5% to 65.4% at 24 h. Highest radiation estimated doses were calculated for parotid glands and kidneys (1.90±1.19 and 0.82±0.25 Gy/GBq respectively). Radiation dose given to the bone marrow was significantly lower than those of kidney and parotid glands (p