TY - JOUR
T1 - Uncertainty in magnetic resonance imaging-based prostate postimplant dosimetry
T2 - Results of a 10-person human observer study, and comparisons with automatic postimplant dosimetry
AU - Sanders, Jeremiah W.
AU - Tang, Chad
AU - Kudchadker, Rajat J.
AU - Venkatesan, Aradhana M.
AU - Mok, Henry
AU - Hanania, Alexander N.
AU - Thames, Howard D.
AU - Bruno, Teresa L.
AU - Starks, Christine
AU - Santiago, Edwin
AU - Cunningham, Mandy
AU - Frank, Steven J.
N1 - Publisher Copyright:
© 2023 American Brachytherapy Society
PY - 2023/11/1
Y1 - 2023/11/1
N2 - PURPOSE: Uncertainties in postimplant quality assessment (QA) for low-dose-rate prostate brachytherapy (LDRPBT) are introduced at two steps: seed localization and contouring. We quantified how interobserver variability (IoV) introduced in both steps impacts dose-volume-histogram (DVH) parameters for MRI-based LDRPBT, and compared it with automatically derived DVH parameters. METHODS AND MATERIALS: Twenty-five patients received MRI-based LDRPBT. Seven clinical observers contoured the prostate and four organs at risk, and 4 dosimetrists performed seed localization, on each MRI. Twenty-eight unique manual postimplant QAs were created for each patient from unique observer pairs. Reference QA and automatic QA were also performed for each patient. IoV of prostate, rectum, and external urinary sphincter (EUS) DVH parameters owing to seed localization and contouring was quantified with coefficients of variation. Automatically derived DVH parameters were compared with those of the reference plans. RESULTS: Coefficients of variation (CoVs) owing to contouring variability (CoVcontours) were significantly higher than those due to seed localization variability (CoVseeds) (median CoVcontours vs. median CoVseeds: prostate D90–15.12% vs. 0.65%, p < 0.001; prostate V100–5.36% vs. 0.37%, p < 0.001; rectum V100–79.23% vs. 8.69%, p < 0.001; EUS V200–107.74% vs. 21.18%, p < 0.001). CoVcontours were lower when the contouring observers were restricted to the 3 radiation oncologists, but were still markedly higher than CoVseeds. Median differences in prostate D90, prostate V100, rectum V100, and EUS V200 between automatically computed and reference dosimetry parameters were 3.16%, 1.63%, −0.00 mL, and −0.00 mL, respectively. CONCLUSIONS: Seed localization introduces substantially less variability in postimplant QA than does contouring for MRI-based LDRPBT. While automatic seed localization may potentially help improve workflow efficiency, it has limited potential for improving the consistency and quality of postimplant dosimetry.
AB - PURPOSE: Uncertainties in postimplant quality assessment (QA) for low-dose-rate prostate brachytherapy (LDRPBT) are introduced at two steps: seed localization and contouring. We quantified how interobserver variability (IoV) introduced in both steps impacts dose-volume-histogram (DVH) parameters for MRI-based LDRPBT, and compared it with automatically derived DVH parameters. METHODS AND MATERIALS: Twenty-five patients received MRI-based LDRPBT. Seven clinical observers contoured the prostate and four organs at risk, and 4 dosimetrists performed seed localization, on each MRI. Twenty-eight unique manual postimplant QAs were created for each patient from unique observer pairs. Reference QA and automatic QA were also performed for each patient. IoV of prostate, rectum, and external urinary sphincter (EUS) DVH parameters owing to seed localization and contouring was quantified with coefficients of variation. Automatically derived DVH parameters were compared with those of the reference plans. RESULTS: Coefficients of variation (CoVs) owing to contouring variability (CoVcontours) were significantly higher than those due to seed localization variability (CoVseeds) (median CoVcontours vs. median CoVseeds: prostate D90–15.12% vs. 0.65%, p < 0.001; prostate V100–5.36% vs. 0.37%, p < 0.001; rectum V100–79.23% vs. 8.69%, p < 0.001; EUS V200–107.74% vs. 21.18%, p < 0.001). CoVcontours were lower when the contouring observers were restricted to the 3 radiation oncologists, but were still markedly higher than CoVseeds. Median differences in prostate D90, prostate V100, rectum V100, and EUS V200 between automatically computed and reference dosimetry parameters were 3.16%, 1.63%, −0.00 mL, and −0.00 mL, respectively. CONCLUSIONS: Seed localization introduces substantially less variability in postimplant QA than does contouring for MRI-based LDRPBT. While automatic seed localization may potentially help improve workflow efficiency, it has limited potential for improving the consistency and quality of postimplant dosimetry.
KW - Brachytherapy
KW - Dosimetry
KW - Interobserver variability
KW - Low-dose-rate
KW - MRI
KW - Postimplant quality assessment
KW - Prostate
KW - Treatment planning
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U2 - 10.1016/j.brachy.2023.08.001
DO - 10.1016/j.brachy.2023.08.001
M3 - Article
C2 - 37716820
AN - SCOPUS:85171667604
SN - 1538-4721
VL - 22
SP - 822
EP - 832
JO - Brachytherapy
JF - Brachytherapy
IS - 6
ER -