International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Long-term oncologic results of salvage radical prostatectomy for locally recurrent prostate cancer after radiotherapy.
Salvage radical prostatectomy (RP) may potentially cure patients who have isolated local prostate cancer recurrence after radiotherapy (RT). We report the long-term cancer control associated with salvage RP in a consecutive cohort of patients and identify the variables associated with disease progression and cancer survival. ⋯ Greater preoperative PSA levels are associated with disease progression and cancer-specific death. Long-term control of locally recurrent prostate cancer after definitive RT is possible when salvage RP is performed early in the course of recurrent disease.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Benefit of using biologic parameters (EUD and NTCP) in IMRT optimization for treatment of intrahepatic tumors.
To investigate whether intensity-modulated radiotherapy (IMRT), optimized using the generalized equivalent uniform dose (gEUD) and normal tissue complication probability (NTCP) models, can increase the safe dose to intrahepatic tumors compared with three-dimensional conformal RT (3D-CRT). A secondary objective was to investigate the optimal beam arrangement for liver IMRT plans. ⋯ We have successfully used mathematical/biologic models directly as cost functions within the optimizing process to produce IMRT plans that maximize the gEUD while maintaining compliance with a well-defined protocol for the treatment of intrahepatic cancer. For both PTV-organ-at-risk overlap and nonoverlap situations, IMRT has the capacity to improve the maximal dose achievable across the PTV, expressed in terms of the gEUD. The use of multiple noncoplanar beams appears to confer an advantage over fewer beams in cases with PTV-organ-at-risk overlap. When liver toxicity is the dose-limiting factor, high gEUD values are obtained most frequently when the field arrangement is chosen to provide the shortest possible transhepatic path length.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Prostate gland motion assessed with cine-magnetic resonance imaging (cine-MRI).
To quantify prostate motion during a radiation therapy treatment using cine-magnetic resonance imaging (cine-MRI) for time frames comparable to that expected in an image-guided radiation therapy treatment session (20-30 min). ⋯ Motion of the prostate and seminal vesicles during a time frame similar to a standard treatment session is reduced compared to that reported in interfraction studies. The most significant predictor for intrafraction prostate motion is the status of rectal filling. A prostate displacement of <3 mm (90%) can be expected for the 20 min after the moment of initial imaging for patients with an empty rectum. This is not the case for patients presenting with full rectum. The determination of appropriate intrafraction margins in radiation therapy to accommodate the time-dependent uncertainty in positional targeting is a topic of ongoing investigations for the on-line image guidance model.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2005
Comparative StudyA permanent breast seed implant as partial breast radiation therapy for early-stage patients: a comparison of palladium-103 and iodine-125 isotopes based on radiation safety considerations.
A permanent breast seed implant (PBSI) technique has been developed as a new form of partial adjuvant radiation therapy for early-stage breast cancer. This study compares iodine-125 ((125)I) and palladium-103 ((103)Pd) isotopes by examining the exposure and effective dose (ED) to a patient's partner. ⋯ PBSI using (103)Pd seeds appears safe because the patient's partner ED is consistently below 5 mSv. The(125)I isotope is not recommended for PBSI.
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To evaluate erectile function after permanent prostate brachytherapy using a validated patient-administered questionnaire and to determine the effect of multiple clinical, treatment, and dosimetric parameters on penile erectile function. ⋯ Using a patient-administered validated quality-of-life instrument, brachytherapy-induced ED occurred in 50% of patients at 3 years. On multivariate analysis, preimplant erectile function and the D(50) to the proximal crura were the best predictors of brachytherapy-related erectile function. Because the proximal penis is the most significant treatment-related predictor of brachytherapy-related ED, techniques to minimize the radiation dose to the proximal penis may result in improved rates of potency preservation.