International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Accuracy of daily image guidance for hypofractionated liver radiotherapy with active breathing control.
A six-fraction, high-precision radiotherapy protocol for unresectable liver cancer has been developed in which active breathing control (ABC) is used to immobilize the liver and daily megavoltage (MV) imaging and repositioning is used to decrease geometric uncertainties. We report the accuracy of setup in the first 20 patients consecutively treated using this approach. ⋯ Image guidance with orthogonal MV imaging and ABC for stereotactic body radiotherapy for liver cancer is feasible, improving setup accuracy compared with ABC without daily imaging and repositioning.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Dose-volume modeling of salivary function in patients with head-and-neck cancer receiving radiotherapy.
We investigated the factors that affect salivary function after head-and-neck radiotherapy (RT), including parotid gland dose-volume effects, potential compensation by less-irradiated gland tissue, and functional recovery over time. ⋯ Stimulated parotid salivary gland dose-volume models strongly correlated with both stimulated salivary function and quality-of-life scores at 6 months after RT. The mean stimulated saliva flow rates improved from 6 to 12 months after RT. Salivary function, in each gland, appeared to be lost exponentially at a rate of approximately 5%/1 Gy of mean dose. Additional research is necessary to distinguish among the models for use in treatment planning. The incidence of xerostomia was significantly decreased when the mean dose of at least one parotid gland was kept to < 25.8 Gy with conventional fractionation. However, even lower mean doses imply increased late salivary function.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Detailed urethral dosimetry in the evaluation of prostate brachytherapy-related urinary morbidity.
To evaluate the relationship between urinary morbidity after prostate brachytherapy and urethral doses calculated at the base, midprostate, apex, and urogenital diaphragm. ⋯ With the routine use of prophylactic alpha blockers and strict adherence to urethral-sparing techniques, detailed urethral dosimetry did not substantially improve the ability to predict urinary morbidity. Neither the average dose to the prostatic urethra nor urethral doses stratified into base, midprostate, apex, or urogenital diaphragm segments predicted for IPSS normalization. Radiation doses of 100%-140% minimum peripheral dose are well tolerated by all segments of the prostatic urethra with resultant tumoricidal doses to foci of periurethral cancer.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Multicenter Study Clinical TrialHealth-related quality of life in men receiving prostate brachytherapy on RTOG 98-05.
To prospectively assess health-related quality of life (HRQOL) during the first year after treatment with prostate brachytherapy (PB) alone for T1c-2a prostate cancer. ⋯ This article represents the first prospective, multi-institutional study of HRQOL in men treated with PB and demonstrates that patients undergoing PB have a very high overall HRQOL. The rate of incontinence by 1 year after PB is low, but many patients continue to have obstructive symptoms at 1 year. Although 78% of 1-year respondents state that they can achieve an erection with or without assistance, almost 50% report a decrease in sexual function.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Comparative StudyIntensity-modulated radiation therapy after hysterectomy: comparison with conventional treatment and sensitivity of the normal-tissue-sparing effect to margin size.
To determine the influence of target-volume expansion on the reduction in small-bowel dose achieved with use of intensity-modulated radiation therapy (IMRT) vs. standard conformal treatment of the pelvis after hysterectomy, and to investigate the influence of patient body habitus on the normal-tissue sparing achieved with use of IMRT. ⋯ Because the small-bowel sparing achieved with use of IMRT is markedly reduced by relatively small expansions of the target volume, accurate target delineation, highly reproducible patient immobilization, and a clear understanding of internal-organ motion are needed to achieve optimal advantage in the use of IMRT over conventional methods of posthysterectomy pelvic radiation therapy.