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Updated: Aug 6, 2026
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Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
Impact of interseed attenuation and tissue composition for permanent prostate implants
Jean-François Carrier1, Luc Beaulieu, François Therriault-Proulx
1Département de Radio-Oncologie et Centre de Recherche en Cancérologie, CHUQ Pavillon L'Hôtel-Dieu de Québec, 11 Côte du Palais, Québec, Quebec G1R 2J6, Canada. francois.carrier.chum@ssss.gouv.qc.ca
Medical Physics
|August 2, 2006
Summary
Prostate seed implant plans are affected by seed density and tissue composition. Higher seed density increases dose loss due to interseed attenuation, while prostate tissue composition significantly impacts dose calculations.
Area of Science:
- Medical Physics
- Radiation Oncology
- Nuclear Medicine
Background:
- Permanent prostate brachytherapy utilizes 125I seed implants for localized prostate cancer treatment.
- Accurate dose calculation is crucial for treatment efficacy and minimizing side effects.
- Traditional dose calculation methods may not fully account for complex physical interactions within the prostate.
Purpose of the Study:
- To evaluate the impact of interseed attenuation and prostate tissue composition on 125I permanent seed implant treatment plans.
- To compare different dose calculation techniques, including Monte Carlo (MC) methods, against the TG-43 standard.
- To investigate the influence of seed density on dose distribution in clinical prostate treatment plans.
Main Methods:
- Utilized Monte Carlo (MC) simulations to model dose distributions for clinical prostate treatment plans.
- Compared four dose calculation techniques: TG-43, superposition MC, full MC in water, and full MC in realistic prostate tissue.
- Investigated the effect of varying seed densities and used ICRP 23 data for prostate tissue composition.
Main Results:
- Seed density significantly influences interseed attenuation, causing dose drops of 1.2% (low density) to 3.0% (high density) in CTV D90.
- Prostate tissue composition resulted in a 4.4%-4.8% difference in D90 compared to water-based MC simulations.
- Overall D90 variations between TG-43 and MC in prostate tissue ranged from 5.8% to 12.8%, depending on patient-specific factors.
Conclusions:
- Interseed attenuation and prostate composition are significant factors affecting dose calculations in 125I permanent seed implants.
- MC simulations in realistic prostate tissue provide a more accurate dose assessment than TG-43, especially for high seed densities.
- These findings highlight the need to consider tissue heterogeneity and interseed effects for improved treatment planning and correlation with clinical outcomes.