Kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy based on multiple small VOIs

Selma Curkic Kapidzic, Johan Gustafsson, Erik Larsson, Lovisa Jessen, Katarina Sjögreen Gleisner

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: The aim was to investigate the use of multiple small VOIs for kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy. Method: The study was based on patient and simulated SPECT images in anthropomorphic geometries. Images were reconstructed using two reconstruction programs (local LundaDose and commercial Hermia) using OS-EM with and without resolution recovery (RR). Five small VOIs were placed to determine the average activity concentration (AC) in each kidney. The study consisted of three steps: (i) determination of the number of iterations for AC convergence based on simulated images; (ii) determination of recovery-coefficients (RCs) for 2 mL VOIs using a separate set of simulated images; (iii) assessment of operator variability in AC estimates for simulated and patient images. Five operators placed the VOIs, using for guidance: a) SPECT/CT with RR, b) SPECT/CT without RR, and c) CT only. For simulated images, time-integrated ACs (TIACs) were evaluated. For patient images, estimated ACs were compared with results of a previous method based on whole-kidney VOIs. Results: Eight iterations and ten subsets were sufficient for both programs and reconstruction settings. Mean RCs (mean ± SD) with RR were 1.03 ± 0.02 (LundaDose) and 1.10 ± 0.03 (Hermia), and without RR 0.91 ± 0.03 (LundaDose) and 0.94 ± 0.03 (Hermia). Most stable and accurate estimates of the AC were obtained using five 2-mL VOIs guided by SPECT/CT with RR, applying them to images without RR, and including an explicit RC for recovery correction. Conclusion: The small VOI method based on five 2-mL VOIs was found efficient and sufficiently accurate for kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy.

Original languageEnglish
Article number103335
JournalPhysica Medica
Volume120
DOIs
Publication statusPublished - 2024 Apr

Subject classification (UKÄ)

  • Radiology, Nuclear Medicine and Medical Imaging

Free keywords

  • Lu-PRRT
  • Dosimetry
  • Kidneys
  • Quantitative SPECT

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