Comparing voxel-based absorbed dosimetry methods in XXXX , liver, lung, and at the liver-lung interface for (90)Y microsphere selective internal radiation therapy.

@entity5 @entity1 @entity1297 @entity96
BACKGROUND: To assess differences between four different @entity1297 ( @entity1297 ) for @entity5 , liver, and lung absorbed doses following (90)Y microsphere selective internal radiation therapy (SIRT) based on (90)Y bremsstrahlung SPECT/CT, a secondary objective was to estimate the sensitivity of liver and lung absorbed doses due to differences in organ segmentation near the liver-lung interface. METHODS: Investigated @entity1297 were Monte Carlo (MC), soft-tissue kernel with density correction (SKD), soft-tissue kernel (SK), and local deposition (LD). Seventeen SIRT cases were analyzed. Mean absorbed doses ([Formula: see text]) were calculated for @entity5 , @entity96 ( @entity96 ), and right lung (RL). Simulations with various SPECT spatial resolutions (FHWMs) and multiple lung shunt fractions (LSs) estimated the accuracy of @entity1297 at the liver-lung interface. Sensitivity of @entity1 RL and @entity96 [Formula: see text] on segmentation near the interface was assessed by excluding portions near the interface. RESULTS: SKD, SK, and LD were within 5  % of MC for @entity5 and @entity96 [Formula: see text]. LD and SKD overestimated RL [Formula: see text] compared to MC on average by 17 and 20  %, respectively; SK underestimated RL [Formula: see text] on average by -60  %. Simulations (20  mm FWHM, 20  % LS) showed that SKD, LD, and MC were within 10  % of the truth deep (>39  mm) in the lung; SK significantly underestimated the absorbed dose deep in the lung by approximately -70  %. All @entity1297 were within 10  % of truth deep (>12  mm) in the liver. Excluding 1, 2, and 3  cm of RL near the interface changed the resulting RL [Formula: see text] by -22, -38, and -48  %, respectively, for all @entity1297 . An average change of -7  % in the @entity96 [Formula: see text] was realized when excluding 3  cm of @entity96 from the interface. [Formula: see text] was realized when excluding 3 cm of @entity96 from the interface. CONCLUSIONS: SKD, SK, and LD are equivalent to MC for @entity5 and @entity96 [Formula: see text]. SK underestimates RL [Formula: see text] relative to MC whereas LD and SKD overestimate. RL [Formula: see text] is strongly influenced by the liver-lung interface.
