International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2004
Evaluation of a contour-alignment technique for CT-guided prostate radiotherapy: an intra- and interobserver study.
The recent introduction of integrated CT/linear accelerator systems may mean that daily CT localization can become a reality in the clinic, possibly allowing further dose escalation to the prostate while limiting unwanted doses to the rectum and bladder. However, the implementation of CT localization is currently impeded by the lack of precise and robust techniques to align the treatment plan with the daily CT images. The purpose of this study was to evaluate a manual alignment technique, in which the gross target volume contours are overlaid on the daily CT images and then shifted to match the structures visible in the images. ⋯ The interobserver uncertainties associated with aligning the gross target volume contours with daily CT images were sufficiently small that this method may be used for daily CT localization of the prostate. The use of a reference image is important to improve the consistency among different users in this technique.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Comparative StudyClinical comparison of two linear-quadratic model-based isoeffect fractionation schemes of high-dose-rate intracavitary brachytherapy for cervical cancer.
Two linear-quadratic model-based isoeffect fractionation schemes of high-dose-rate intracavitary brachytherapy (HDR-IC) were used to treat cervical cancer in two consecutive periods. Patient outcomes and complications were analyzed and compared. ⋯ The treatment results of the two groups maintained similar outcomes, while the complications decreased. The linear-quadratic model correctly predicted this outcome. Biologically, the manipulation of the fraction size in our study suggested that the sensitivity of the late responding tissue to the fractional change from 7.2 Gy to 4.8 Gy in HDR-IC is high and detectable clinically. The success, however, had its limitations, and the improvement was confined to low-grade complications.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Repeat gamma knife radiosurgery for refractory or recurrent trigeminal neuralgia: treatment outcomes and quality-of-life assessment.
Stereotactic radiosurgery (SRS) has become a minimally invasive treatment modality for patients with refractory trigeminal neuralgia. It is unclear, however, how best to treat patients with pain that is refractory or recurrent after initial SRS. We report on treatment outcomes and quality of life for patients treated with repeated SRS for refractory or recurrent trigeminal neuralgia. ⋯ Despite a modest dose reduction, repeat SRS provided similar rates of complete pain control as the initial procedure, but was not effective for patients with no response to initial treatment. Repeat SRS was more efficacious for those patients who experienced longer periods of pain relief after the initial SRS. The incidence of complications was not significantly different from that observed for initial SRS. In this series, most patients had significant improvements in quality of life.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Stereotatic radiosurgery of 468 brain metastases < or =2 cm: implications for SRS dose and whole brain radiation therapy.
The national standard stereostatic radiosurgery (SRS) dose for brain metastases < or =2 cm is 24 Gy as established by the Radiation Therapy Oncology Group study 90-05, in which planned whole brain radiotherapy (WBRT) was not used. On the basis of our institutional experience, the goal of this study was to determine the optimal SRS dose and influence of WBRT on local tumor control among 468 < or =2-cm metastases. ⋯ First, optimal control of brain metastasis < or =2 cm was seen with 20-Gy SRS combined with planned WBRT. Second, SRS doses >20 Gy resulted in no obvious improvement in local control and appeared to be associated with a greater rate of complications.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Recurrences near base of skull after IMRT for head-and-neck cancer: implications for target delineation in high neck and for parotid gland sparing.
Locoregional (LR) failures near the base of the skull, and their relationships to the targets in the high neck, were examined in a series of patients who underwent intensity-modulated radiotherapy (IMRT) for head-and-neck cancer. ⋯ These results suggest that when the contralateral node-negative side of the neck has a high risk of subclinical metastasis, it is adequate to include the SD nodes as the cranial-most Level II nodal target in non-nasopharyngeal head-and-neck cancer. In the node-positive side of the neck, this nodal level should be delineated more cranially. The RP nodal targets should be delineated more cranially. The RP nodal targets should be delineated bilaterally and should extend to the base of the skull, rather than to the top of C1. These guidelines allowed substantial sparing of the contralateral parotid gland. The results of this series validate a consensus for target delineation adopted recently by cooperative radiotherapy groups.