title: Kidney dosimetry in ¹⁷⁷Lu and ⁹⁰Y peptide receptor radionuclide therapy: influence of image timing, time-activity integration method, and risk factors.
abstract: Kidney dosimetry in (177)Lu and (90)Y PRRT requires 3 to 6 whole-body/SPECT scans to extrapolate the peptide kinetics, and it is considered time and resource consuming. We investigated the most adequate timing for imaging and time-activity interpolating curve, as well as the performance of a simplified dosimetry, by means of just 1-2 scans. Finally the influence of risk factors and of the peptide (DOTATOC versus DOTATATE) is considered. 28 patients treated at first cycle with (177)Lu DOTATATE and 30 with (177)Lu DOTATOC underwent SPECT scans at 2 and 6 hours, 1, 2, and 3 days after the radiopharmaceutical injection. Dose was calculated with our simplified method, as well as the ones most used in the clinic, that is, trapezoids, monoexponential, and biexponential functions. The same was done skipping the 6 h and the 3 d points. We found that data should be collected until 100 h for (177)Lu therapy and 70 h for (90)Y therapy, otherwise the dose calculation is strongly influenced by the curve interpolating the data and should be carefully chosen. Risk factors (hypertension, diabetes) cause a rather statistically significant 20% increase in dose (t-test, P < 0.10), with DOTATATE affecting an increase of 25% compared to DOTATOC (t-test, P < 0.05).
authors.affiliation: Medical Physics Department, European Institute of Oncology, 20141 Milan, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Guerriero
authors.forename: M E
authors.initials: ME
authors.lastname: Ferrari
authors.forename: F
authors.initials: F
authors.lastname: Botta
authors.forename: F
authors.initials: F
authors.lastname: Fioroni
authors.forename: E
authors.initials: E
authors.lastname: Grassi
authors.forename: A
authors.initials: A
authors.lastname: Versari
authors.forename: A
authors.initials: A
authors.lastname: Sarnelli
authors.forename: M
authors.initials: M
authors.lastname: Pacilio
authors.forename: E
authors.initials: E
authors.lastname: Amato
authors.forename: L
authors.initials: L
authors.lastname: Strigari
authors.forename: L
authors.initials: L
authors.lastname: Bodei
authors.forename: G
authors.initials: G
authors.lastname: Paganelli
authors.forename: M
authors.initials: M
authors.lastname: Iori
authors.forename: G
authors.initials: G
authors.lastname: Pedroli
authors.forename: M
authors.initials: M
authors.lastname: Cremonesi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002138:Calibration; D015331:Cohort Studies; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging*; D007700:Kinetics; D008875:Middle Aged; D015282:Octreotide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D011874:Radiometry; D018000:Receptors, Peptide / Q000378:metabolism*; D012307:Risk Factors; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: C539274:90Y-octreotate, DOTA(0)-Tyr(3)-Thr(8)-; D009942:Organometallic Compounds; D018000:Receptors, Peptide; C447941:lutetium Lu 177 dotatate; D015282:Octreotide; C106246:Edotreotide