Improved dosimetry for targeted radionuclide therapy using nonrigid registration on sequential SPECT images

Abstract

These results demonstrated that nonrigid registration of sequential QSPECT images is feasible for TRT and improves the accuracy of 3D dosimetry.

Effect of image registration on 3D absorbed dose calculations in 177 Lu-DOTATOC peptide receptor radionuclide therapy

“…Whereas several works about the deformable registration in external radiation therapy have been published with plenty of results (e.g. in the work of Pukala J et al [27]), in MRT only few papers are available [2,13]. Also, a recent work shows the superiority of deformable registration of PET/CT to planning CT by multiple positional metrics, compared to rigid registration [28].…”

“…Ao et al [13], on the other hand, didn't present a complete study. They showed that deformable image registration can affect the accuracy of 3D dosimetry with 111 In-Zevalin, compared to rigid registration, but they based their study on a modelled phantom population.…”

Technical Note: Virtual CT for reducing CT dose in targeted radionuclide therapy dosimetry

“…Nonuniform distribution of activity was simulated in the lungs with airway activity set to zero, differing from that in lung parenchyma. The time‐varying 111 In distributions of each target organ were used to simulate SPECT scans acquired at 1, 12, 24, 72, and 144 h postinjection . To simulate the nonrigid organs deformations, rotations, and translations for each individual organ were randomly simulated within five pixels or degrees while the volume changes were kept within 5%.…”

“…For vCT and rCT protocols, first we semi‐automatically segmented the target organs, that is, liver, spleen, kidneys, and lungs at all time points on respective vCTs and rCTs images. We then applied organ‐by‐organ nonrigid registration . For the conventional 1CT protocol, as some organ‐of‐interest regions cannot be delineated from SPECT images at later time points, whole‐body SPECT registrations were performed while the single CT was used for organ segmentation.…”

Voxel‐based dosimetry is superior to mean absorbed dose approach for establishing dose‐effect relationship in targeted radionuclide therapy

“…In sequential SPECT, various authors demonstrated with simulations that good accuracy in cumulative DVH images can be obtained using nonrigid coregistration . Remarkable intra‐lesion heterogeneity of absorbed dose deposition was reported in 124 I PET dosimetry of metastatic differentiated thyroid cancer, but its potential impact on response was not fully investigated.…”