International journal of radiation oncology, biology, physics
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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
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
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.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Locoregional recurrence rates and prognostic factors for failure in node-negative patients treated with mastectomy: implications for postmastectomy radiation.
Postmastectomy radiation therapy (PMRT) reduces locoregional recurrence (LRR) of breast cancer. Survival appears improved in patients at higher risk for LRR. This study addresses whether subsets of node-negative patients with sufficiently high risk of LRR might benefit from PMRT. ⋯ Postmastectomy radiation therapy has not been recommended for node-negative patients because the LRR rate is low in that population overall. This study suggests, however, that node-negative patients with multiple risk factors, including close margins, T2 or larger tumors, premenopausal status, and LVI, are at higher risk for LRR and might benefit from PMRT. Because the chest wall is the most common site of failure, treating the chest wall alone in these patients to minimize toxicity is reasonable.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Assessment of the tumor microenvironment in cervix cancer using dynamic contrast enhanced CT, interstitial fluid pressure and oxygen measurements.
Interstitial fluid pressure (IFP) and oxygen (pO(2)) measurements are prognostic factors in cervical cancer. The purpose of this study was to determine the relationship between IFP and oxygenation and parameters derived from dynamic contrast-enhanced computed tomography (DCE-CT). ⋯ There is a moderately positive, correlation between tumor oxygenation and BF as well as RE and HP5. Further study is required to determine if DCE-CT parameters are useful predictors of tumor behavior in cervical cancer.