SU‐FF‐J‐33: Image Guided Radiotherapy in Prostate Localization: A Comparison of Ultrasound Modalities to Implanted Seed Markers and Assessment of Intrafractional Prostate Motion

B. Weyers; C. wu; S. Goddu; J. Michalski

doi:10.1118/1.2760538

SU‐FF‐J‐33: Image Guided Radiotherapy in Prostate Localization: A Comparison of Ultrasound Modalities to Implanted Seed Markers and Assessment of Intrafractional Prostate Motion

B. Weyers, C. wu, S. Goddu, J. Michalski

Research output: Contribution to journal › Article › peer-review

Abstract

Purpose: To compare 2D (BAT) and 3D (IBeam) ultrasounds with seed markers (SM) for prostate localization, and to assess intrafractional prostate motion during external beam radiotherapy (EBRT). Method and Materials: Prior to daily prostate localization with SM, patients underwent localization with two ultrasound systems for one week and with one ultrasound system for remaining treatments. Ultrasound shifts were prospectively recorded and patients were shifted as per SM alignment. The differences in lateral (LR), craniocaudal (CC) and anterior‐posterior (AP) directions were compared assuming SM revealed the true position of the prostate. Intrafraction motion of the prostate was assessed by repeating the SM after EBRT treatment on four fractions. Results: From 20 patients, 455 I‐Beam and 343 BAT ultrasound scans were compared to SM localizations. I‐Beam had a mean error ± sd of 0.6±3.3mm in the LR direction, 2.2±4.8mm (CC) and 0.2±3.8mm (AP). BAT had a mean error ± sd of 0.0±3.8mm (LR), 0.8±4.5mm (CC), and −1.5±4.3mm (AP). Deviations >5mm occurred in 11%, 32% and 18% in the LR, CC and AP directions respectively for I‐Beam, and 11%, 24% and 23% respectively for BAT. Deviations >1cm occurred in 7% in the CC direction for I‐Beam. Intrafraction prostate motion is minimal with a mean displacement ⩽1.5mm. The greatest movement is in the AP direction with 4% of patients having >5mm displacement. Conclusion: Target localization with two US systems provide different results than SM localization. Our data suggest that PTV margin guidelines for BAT and I‐Beam should be greater than those for SM. The US margin requirements may also need to be greater than if no daily localization is performed. In addition, intrafractional prostate motion is minimal with large displacements occurring in <5% of patients. We have adopted seed markers for daily prostate localization at our institution.

Original language	English
Pages (from-to)	2375
Number of pages	1
Journal	Medical physics
Volume	34
Issue number	6
DOIs	https://doi.org/10.1118/1.2760538
State	Published - Jun 2007

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@article{bf6a40b44ef54bcfa72f1f66f9bed311,

title = "SU‐FF‐J‐33: Image Guided Radiotherapy in Prostate Localization: A Comparison of Ultrasound Modalities to Implanted Seed Markers and Assessment of Intrafractional Prostate Motion",

abstract = "Purpose: To compare 2D (BAT) and 3D (IBeam) ultrasounds with seed markers (SM) for prostate localization, and to assess intrafractional prostate motion during external beam radiotherapy (EBRT). Method and Materials: Prior to daily prostate localization with SM, patients underwent localization with two ultrasound systems for one week and with one ultrasound system for remaining treatments. Ultrasound shifts were prospectively recorded and patients were shifted as per SM alignment. The differences in lateral (LR), craniocaudal (CC) and anterior‐posterior (AP) directions were compared assuming SM revealed the true position of the prostate. Intrafraction motion of the prostate was assessed by repeating the SM after EBRT treatment on four fractions. Results: From 20 patients, 455 I‐Beam and 343 BAT ultrasound scans were compared to SM localizations. I‐Beam had a mean error ± sd of 0.6±3.3mm in the LR direction, 2.2±4.8mm (CC) and 0.2±3.8mm (AP). BAT had a mean error ± sd of 0.0±3.8mm (LR), 0.8±4.5mm (CC), and −1.5±4.3mm (AP). Deviations >5mm occurred in 11%, 32% and 18% in the LR, CC and AP directions respectively for I‐Beam, and 11%, 24% and 23% respectively for BAT. Deviations >1cm occurred in 7% in the CC direction for I‐Beam. Intrafraction prostate motion is minimal with a mean displacement ⩽1.5mm. The greatest movement is in the AP direction with 4% of patients having >5mm displacement. Conclusion: Target localization with two US systems provide different results than SM localization. Our data suggest that PTV margin guidelines for BAT and I‐Beam should be greater than those for SM. The US margin requirements may also need to be greater than if no daily localization is performed. In addition, intrafractional prostate motion is minimal with large displacements occurring in <5% of patients. We have adopted seed markers for daily prostate localization at our institution.",

author = "B. Weyers and C. wu and S. Goddu and J. Michalski",

year = "2007",

month = jun,

doi = "10.1118/1.2760538",

language = "English",

volume = "34",

pages = "2375",

journal = "Medical physics",

issn = "0094-2405",

number = "6",

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T2 - Image Guided Radiotherapy in Prostate Localization: A Comparison of Ultrasound Modalities to Implanted Seed Markers and Assessment of Intrafractional Prostate Motion

AU - Weyers, B.

AU - wu, C.

AU - Goddu, S.

AU - Michalski, J.

PY - 2007/6

Y1 - 2007/6

N2 - Purpose: To compare 2D (BAT) and 3D (IBeam) ultrasounds with seed markers (SM) for prostate localization, and to assess intrafractional prostate motion during external beam radiotherapy (EBRT). Method and Materials: Prior to daily prostate localization with SM, patients underwent localization with two ultrasound systems for one week and with one ultrasound system for remaining treatments. Ultrasound shifts were prospectively recorded and patients were shifted as per SM alignment. The differences in lateral (LR), craniocaudal (CC) and anterior‐posterior (AP) directions were compared assuming SM revealed the true position of the prostate. Intrafraction motion of the prostate was assessed by repeating the SM after EBRT treatment on four fractions. Results: From 20 patients, 455 I‐Beam and 343 BAT ultrasound scans were compared to SM localizations. I‐Beam had a mean error ± sd of 0.6±3.3mm in the LR direction, 2.2±4.8mm (CC) and 0.2±3.8mm (AP). BAT had a mean error ± sd of 0.0±3.8mm (LR), 0.8±4.5mm (CC), and −1.5±4.3mm (AP). Deviations >5mm occurred in 11%, 32% and 18% in the LR, CC and AP directions respectively for I‐Beam, and 11%, 24% and 23% respectively for BAT. Deviations >1cm occurred in 7% in the CC direction for I‐Beam. Intrafraction prostate motion is minimal with a mean displacement ⩽1.5mm. The greatest movement is in the AP direction with 4% of patients having >5mm displacement. Conclusion: Target localization with two US systems provide different results than SM localization. Our data suggest that PTV margin guidelines for BAT and I‐Beam should be greater than those for SM. The US margin requirements may also need to be greater than if no daily localization is performed. In addition, intrafractional prostate motion is minimal with large displacements occurring in <5% of patients. We have adopted seed markers for daily prostate localization at our institution.

AB - Purpose: To compare 2D (BAT) and 3D (IBeam) ultrasounds with seed markers (SM) for prostate localization, and to assess intrafractional prostate motion during external beam radiotherapy (EBRT). Method and Materials: Prior to daily prostate localization with SM, patients underwent localization with two ultrasound systems for one week and with one ultrasound system for remaining treatments. Ultrasound shifts were prospectively recorded and patients were shifted as per SM alignment. The differences in lateral (LR), craniocaudal (CC) and anterior‐posterior (AP) directions were compared assuming SM revealed the true position of the prostate. Intrafraction motion of the prostate was assessed by repeating the SM after EBRT treatment on four fractions. Results: From 20 patients, 455 I‐Beam and 343 BAT ultrasound scans were compared to SM localizations. I‐Beam had a mean error ± sd of 0.6±3.3mm in the LR direction, 2.2±4.8mm (CC) and 0.2±3.8mm (AP). BAT had a mean error ± sd of 0.0±3.8mm (LR), 0.8±4.5mm (CC), and −1.5±4.3mm (AP). Deviations >5mm occurred in 11%, 32% and 18% in the LR, CC and AP directions respectively for I‐Beam, and 11%, 24% and 23% respectively for BAT. Deviations >1cm occurred in 7% in the CC direction for I‐Beam. Intrafraction prostate motion is minimal with a mean displacement ⩽1.5mm. The greatest movement is in the AP direction with 4% of patients having >5mm displacement. Conclusion: Target localization with two US systems provide different results than SM localization. Our data suggest that PTV margin guidelines for BAT and I‐Beam should be greater than those for SM. The US margin requirements may also need to be greater than if no daily localization is performed. In addition, intrafractional prostate motion is minimal with large displacements occurring in <5% of patients. We have adopted seed markers for daily prostate localization at our institution.

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SU‐FF‐J‐33: Image Guided Radiotherapy in Prostate Localization: A Comparison of Ultrasound Modalities to Implanted Seed Markers and Assessment of Intrafractional Prostate Motion

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