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

Mikell JK, Mahvash A, Siman W, Mourtada F, Kappadath SC - EJNMMI Phys (2015)

Bottom Line: 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 VBDM.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1155 Pressler St, Unit 1352, Houston, TX, 77030, USA.

ABSTRACT

Background: To assess differences between four different voxel-based dosimetry methods (VBDM) for tumor, 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 VBDM 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 tumor, non-tumoral liver (NL), and right lung (RL). Simulations with various SPECT spatial resolutions (FHWMs) and multiple lung shunt fractions (LSs) estimated the accuracy of VBDM at the liver-lung interface. Sensitivity of patient RL and NL [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 tumor and NL [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 VBDM 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 VBDM. An average change of -7 % in the NL [Formula: see text] was realized when excluding 3 cm of NL from the interface. [Formula: see text] was realized when excluding 3 cm of NL from the interface.

Conclusions: SKD, SK, and LD are equivalent to MC for tumor and NL [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.

No MeSH data available.


Related in: MedlinePlus

Sagittal view through liver and RL illustrating excluded regions from the liver-lung interface. Remainder RL (red), excluded RL (yellow), excluded liver (blue), and remainder liver (pink)
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Fig1: Sagittal view through liver and RL illustrating excluded regions from the liver-lung interface. Remainder RL (red), excluded RL (yellow), excluded liver (blue), and remainder liver (pink)

Mentions: To assess sensitivity of NL, RL, and total liver to the liver-lung interface in patient data, we generated remainder VOI for total liver, NL, and RL by excluding regions extending 1, 2, or 3 cm from the liver-lung interface into both the liver and lung. The sensitivity of on segmentation was analyzed in Excel by plotting the to the original VOI as a function of the to the remainder VOIs and fitting a line to the data. Figure 1 shows an example of the remainder VOI generation.Fig. 1


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

Mikell JK, Mahvash A, Siman W, Mourtada F, Kappadath SC - EJNMMI Phys (2015)

Sagittal view through liver and RL illustrating excluded regions from the liver-lung interface. Remainder RL (red), excluded RL (yellow), excluded liver (blue), and remainder liver (pink)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4538912&req=5

Fig1: Sagittal view through liver and RL illustrating excluded regions from the liver-lung interface. Remainder RL (red), excluded RL (yellow), excluded liver (blue), and remainder liver (pink)
Mentions: To assess sensitivity of NL, RL, and total liver to the liver-lung interface in patient data, we generated remainder VOI for total liver, NL, and RL by excluding regions extending 1, 2, or 3 cm from the liver-lung interface into both the liver and lung. The sensitivity of on segmentation was analyzed in Excel by plotting the to the original VOI as a function of the to the remainder VOIs and fitting a line to the data. Figure 1 shows an example of the remainder VOI generation.Fig. 1

Bottom Line: 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 VBDM.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1155 Pressler St, Unit 1352, Houston, TX, 77030, USA.

ABSTRACT

Background: To assess differences between four different voxel-based dosimetry methods (VBDM) for tumor, 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 VBDM 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 tumor, non-tumoral liver (NL), and right lung (RL). Simulations with various SPECT spatial resolutions (FHWMs) and multiple lung shunt fractions (LSs) estimated the accuracy of VBDM at the liver-lung interface. Sensitivity of patient RL and NL [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 tumor and NL [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 VBDM 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 VBDM. An average change of -7 % in the NL [Formula: see text] was realized when excluding 3 cm of NL from the interface. [Formula: see text] was realized when excluding 3 cm of NL from the interface.

Conclusions: SKD, SK, and LD are equivalent to MC for tumor and NL [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.

No MeSH data available.


Related in: MedlinePlus