Three-dimensional radiobiological dosimetry of kidneys for treatment planning in peptide receptor radionuclide therapy

Journal Article · Mon Oct 15 04:00:00 EDT 2012 · Medical Physics

DOI:https://doi.org/10.1118/1.4752213· OSTI ID:22099039

Baechler, Sebastien; Hobbs, Robert F.; Boubaker, Ariane; Buchegger, Franz; Bin, He; Frey, Eric C.; Sgouros, George ^[1]

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1. Institute of Radiation Physics, Lausanne University Hospital, 1007 Lausanne (Switzerland)

Purpose: Peptide receptor radionuclide therapy (PRRT) delivers high absorbed doses to kidneys and may lead to permanent nephropathy. Reliable dosimetry of kidneys is thus critical for safe and effective PRRT. The aim of this work was to assess the feasibility of planning PRRT based on 3D radiobiological dosimetry (3D-RD) in order to optimize both the amount of activity to administer and the fractionation scheme, while limiting the absorbed dose and the biological effective dose (BED) to the renal cortex. Methods: Planar and SPECT data were available for a patient examined with {sup 111}In-DTPA-octreotide at 0.5 (planar only), 4, 24, and 48 h post-injection. Absorbed dose and BED distributions were calculated for common therapeutic radionuclides, i.e., {sup 111}In, {sup 90}Y and {sup 177}Lu, using the 3D-RD methodology. Dose-volume histograms were computed and mean absorbed doses to kidneys, renal cortices, and medullae were compared with results obtained using the MIRD schema (S-values) with the multiregion kidney dosimetry model. Two different treatment planning approaches based on (1) the fixed absorbed dose to the cortex and (2) the fixed BED to the cortex were then considered to optimize the activity to administer by varying the number of fractions. Results: Mean absorbed doses calculated with 3D-RD were in good agreement with those obtained with S-value-based SPECT dosimetry for {sup 90}Y and {sup 177}Lu. Nevertheless, for {sup 111}In, differences of 14% and 22% were found for the whole kidneys and the cortex, respectively. Moreover, the authors found that planar-based dosimetry systematically underestimates the absorbed dose in comparison with SPECT-based methods, up to 32%. Regarding the 3D-RD-based treatment planning using a fixed BED constraint to the renal cortex, the optimal number of fractions was found to be 3 or 4, depending on the radionuclide administered and the value of the fixed BED. Cumulative activities obtained using the proposed simulated treatment planning are compatible with real activities administered to patients in PRRT. Conclusions: The 3D-RD treatment planning approach based on the fixed BED was found to be the method of choice for clinical implementation in PRRT by providing realistic activity to administer and number of cycles. While dividing the activity in several cycles is important to reduce renal toxicity, the clinical outcome of fractionated PRRT should be investigated in the future.

• OSTI ID: 22099039
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 10 Vol. 39; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
61 RADIATION PROTECTION AND DOSIMETRY
62 RADIOLOGY AND NUCLEAR MEDICINE
DOSIMETRY
DTPA
FRACTIONATION
INDIUM 111
KIDNEYS
LUTETIUM 177
OPTIMIZATION
PATIENTS
PEPTIDES
PLANNING
RADIATION DOSES
RADIOPHARMACEUTICALS
RADIOTHERAPY
RECEPTORS
SIMULATION
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
TOXICITY
YTTRIUM 90