Investigating the dosimetric and tumor control consequences of prostate seed loss and migration

Courtney Knaup, Panayiotis Mavroidis, Carlos Esquivel, Sotirios Stathakis, Gregory P Swanson, Dimos Baltas, Nikos Papanikolaou

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Purpose: Low dose-rate brachytherapy is commonly used to treat prostate cancer. However, once implanted, the seeds are vulnerable to loss and movement. The goal of this work is to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. Methods: Five patients were used in this study. For each patient three treatment plans were created using Iodine-125, Palladium-103, and Cesium-131 seeds. The three seeds that were closest to the urethra were identified and modeled as the seeds lost through the urethra. The three seeds closest to the exterior of prostatic capsule were identified and modeled as those lost from the prostate periphery. The seed locations and organ contours were exported from Prowess and used by in-house software to perform the dosimetric and radiobiological evaluation. Seed loss was simulated by simultaneously removing 1, 2, or 3 seeds near the urethra 0, 2, or 4 days after the implant or removing seeds near the exterior of the prostate 14, 21, or 28 days after the implant. Results: Loss of one, two or three seeds through the urethra results in a D90 reduction of 2, 5, and 7 loss, respectively. Due to delayed loss of peripheral seeds, the dosimetric effects are less severe than for loss through the urethra. However, while the dose reduction is modest for multiple lost seeds, the reduction in tumor control probability was minimal. Conclusions: The goal of this work was to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. The results presented show that loss of multiple seeds can cause a substantial reduction of D90 coverage. However, for the patients in this study the dose reduction was not seen to reduce tumor control probability.

Original languageEnglish (US)
Pages (from-to)3291-3298
Number of pages8
JournalMedical Physics
Volume39
Issue number6
DOIs
StatePublished - Jun 2012

Fingerprint

Prostate
Seeds
Neoplasms
Urethra
Brachytherapy
Cesium
Palladium
Iodine
Capsules
Prostatic Neoplasms
Software

Keywords

  • brachytherapy
  • prostate
  • radiobiology

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

Cite this

Knaup, C., Mavroidis, P., Esquivel, C., Stathakis, S., Swanson, G. P., Baltas, D., & Papanikolaou, N. (2012). Investigating the dosimetric and tumor control consequences of prostate seed loss and migration. Medical Physics, 39(6), 3291-3298. https://doi.org/10.1118/1.4712227

Investigating the dosimetric and tumor control consequences of prostate seed loss and migration. / Knaup, Courtney; Mavroidis, Panayiotis; Esquivel, Carlos; Stathakis, Sotirios; Swanson, Gregory P; Baltas, Dimos; Papanikolaou, Nikos.

In: Medical Physics, Vol. 39, No. 6, 06.2012, p. 3291-3298.

Research output: Contribution to journalArticle

Knaup, C, Mavroidis, P, Esquivel, C, Stathakis, S, Swanson, GP, Baltas, D & Papanikolaou, N 2012, 'Investigating the dosimetric and tumor control consequences of prostate seed loss and migration', Medical Physics, vol. 39, no. 6, pp. 3291-3298. https://doi.org/10.1118/1.4712227
Knaup C, Mavroidis P, Esquivel C, Stathakis S, Swanson GP, Baltas D et al. Investigating the dosimetric and tumor control consequences of prostate seed loss and migration. Medical Physics. 2012 Jun;39(6):3291-3298. https://doi.org/10.1118/1.4712227
Knaup, Courtney ; Mavroidis, Panayiotis ; Esquivel, Carlos ; Stathakis, Sotirios ; Swanson, Gregory P ; Baltas, Dimos ; Papanikolaou, Nikos. / Investigating the dosimetric and tumor control consequences of prostate seed loss and migration. In: Medical Physics. 2012 ; Vol. 39, No. 6. pp. 3291-3298.
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abstract = "Purpose: Low dose-rate brachytherapy is commonly used to treat prostate cancer. However, once implanted, the seeds are vulnerable to loss and movement. The goal of this work is to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. Methods: Five patients were used in this study. For each patient three treatment plans were created using Iodine-125, Palladium-103, and Cesium-131 seeds. The three seeds that were closest to the urethra were identified and modeled as the seeds lost through the urethra. The three seeds closest to the exterior of prostatic capsule were identified and modeled as those lost from the prostate periphery. The seed locations and organ contours were exported from Prowess and used by in-house software to perform the dosimetric and radiobiological evaluation. Seed loss was simulated by simultaneously removing 1, 2, or 3 seeds near the urethra 0, 2, or 4 days after the implant or removing seeds near the exterior of the prostate 14, 21, or 28 days after the implant. Results: Loss of one, two or three seeds through the urethra results in a D90 reduction of 2, 5, and 7 loss, respectively. Due to delayed loss of peripheral seeds, the dosimetric effects are less severe than for loss through the urethra. However, while the dose reduction is modest for multiple lost seeds, the reduction in tumor control probability was minimal. Conclusions: The goal of this work was to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. The results presented show that loss of multiple seeds can cause a substantial reduction of D90 coverage. However, for the patients in this study the dose reduction was not seen to reduce tumor control probability.",
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