International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Comparative StudyProstate seed implantation using 3D-computer assisted intraoperative planning vs. a standard look-up nomogram: Improved target conformality with reduction in urethral and rectal wall dose.
To compare dosimetric outcomes between two real-time prostate seed implantation (PSI) techniques to evaluate the impact of three-dimensional (3D) intraoperative computer planning on target coverage, conformality, and preset urethral and rectal dose constraints. ⋯ The adoption of 3D computer intraoperative dose planning and optimization for prostate seed implantation resulted in dramatic reductions in urethral and rectal wall doses, while consistently producing excellent target coverage with reduced dose variability above 180 Gy and below 140 Gy, compared with the use of a standard look-up nomogram. Additionally, the reduction in total mCi and number of seeds needed to achieve improved conformality was substantial and may have implications for cost savings.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Comparative StudyBiologic comparison of partial breast irradiation protocols.
To analyze the dose/fractionation schedules currently used in ongoing clinical trials of partial breast irradiation (PBI) by comparing their biologically effective dose (BED) values to those of three standard whole breast protocols commonly used after segmental mastectomy in the treatment of breast cancer. ⋯ Biologically effective dose modeling raises the concern that inadequate doses might be delivered by PBI to ensure optimal in-field tumor control.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Comparison of rectal dose-wall histogram versus dose-volume histogram for modeling the incidence of late rectal bleeding after radiotherapy.
To compare the fits of normal-tissue complication probability (NTCP) models based on rectal dose-wall histograms (DWHs) vs. dose-volume histograms (DVHs) when the two are used to analyze a common set of late rectal toxicity data. ⋯ A consistent, although modest, improvement occurs in the fits of NTCP models to the UTMDACC 2-year late rectal bleeding data when the fit is based on the rectal dose-wall histogram instead of on the dose-volume histogram for entire rectum, including contents.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Magnetic resonance assessment of prostate localization variability in intensity-modulated radiotherapy for prostate cancer.
To measure prostate motion with magnetic resonance imaging (MRI) during a course of intensity-modulated radiotherapy. ⋯ All pretreatment positions were representative of the subsequent on-treatment positions. A clinical target volume (CTV) expansion of 5.3 mm in any direction was sufficient to ascertain a 95% coverage of the CTV within the planning target volume (PTV), provided that a rectal suppository is administered to avoid rectal overdistension and that the patient has a comfortably filled bladder (<300 mL).