International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Assessment of residual error for online cone-beam CT-guided treatment of prostate cancer patients.
Kilovoltage cone-beam CT (CBCT) implemented on board a medical accelerator is available for image-guidance applications in our clinic. The objective of this work was to assess the magnitude and stability of the residual setup error associated with CBCT online-guided prostate cancer patient setup. Residual error pertains to the uncertainty in image registration, the limited mechanical accuracy, and the intrafraction motion during imaging and treatment. ⋯ On the basis of the residual setup error measurements, the margin required after online CBCT correction for the patients enrolled in this study would be approximatively 3 mm and is considered to be a lower limit owing to the small intrafraction motion observed. The discrepancy between setup corrections derived from registration using coils or soft tissue can be due in part to the lack of complete three-dimensional information with the coils or to the difficulty in prostate delineation and requires further study.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
Comparative StudyComparison of low and high dose rate brachytherapy in the treatment of uterine cervix cancer. Retrospective analysis of two sequential series.
This retrospective analysis aims to report on the comparative outcome of cervical cancer patients treated with low dose rate (LDR) and high dose rate (HDR) brachytherapy. ⋯ This comparative series suggests similar outcome for Stages I and II patients treated with either HDR or LDR brachytherapy. Lower overall and disease-free survival and marginally lower local control were observed for Stage III patients treated with HDR brachytherapy. Less late rectal complications were observed in the HDR group patients. These findings were probably the result of the relatively low HDR brachytherapy dose delivered at Point A.
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Int. J. Radiat. Oncol. Biol. Phys. · Jul 2005
The impact of whole-brain radiation therapy on the long-term control and morbidity of patients surviving more than one year after gamma knife radiosurgery for brain metastases.
To better analyze how whole-brain radiotherapy (WBXRT) affects long-term tumor control and toxicity from the initial stereotactic radiosurgery (SRS) for brain metastases, we studied these outcomes in patients who had survived at least 1 year from SRS. ⋯ In this retrospective study of 1-year survivors of SRS for brain metastases, the addition of concurrent WBXRT to SRS was associated with an improved local control rate in patient subsets with tumor volume > or =2 cc, peripheral dose < or =16 Gy, single metastases, nonradioresistant tumors, and specifically lung cancer metastases. A trend was noted for improved distal intracranial control for patients having nonradioresistant tumors. Distant intracranial relapse >1 year posttreatment is a significant problem with or without initial WBXRT.
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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
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.