International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2004
A preliminary study of the role of modulated electron beams in intensity modulated radiotherapy, using automated beam orientation and modality selection.
To develop an algorithm for optimal beam arrangement selection in intensity-modulated radiotherapy (IMRT) of mixed photon and electron beams. To apply this algorithm to study the utility of modulated electron beams in the context of IMRT planning. ⋯ In the two cases analyzed using the selection algorithm, the primary role of modulated electrons differs based on treatment site-normal tissue dose reduction in breast and target homogeneity improvement in head and neck. Although this preliminary study with two cases appears to suggest that the role of intensity-modulated electrons differs based on treatment site, further investigation of large numbers of cases and varied treatment sites are required to establish a definitive conclusion.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Pilot study of postoperative reirradiation, chemotherapy, and amifostine after surgical salvage for recurrent head-and-neck cancer.
Salvage surgery alone after radiotherapy (RT) failure for locally advanced head-and-neck cancer is frequently unsuccessful because of subsequent recurrence. We designed a prospective protocol to determine the feasibility, toxicity, and preliminary efficacy of a regimen of postoperative reirradiation, chemotherapy and the radioprotector amifostine after salvage head-and-neck surgery. ⋯ This regimen of postoperative reirradiation/chemotherapy plus amifostine is feasible and was well tolerated acutely, with encouraging oncologic efficacy. However, the incidence and severity of late effects was significant and suggests that modifications are necessary for future studies in this patient population.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2004
Erythropoietin-induced reduction of hypoxia before and during fractionated irradiation contributes to improvement of radioresponse in human glioma xenografts.
Our study investigated the influence of recombinant human erythropoietin (rHuEPO) treatment, inducing raised hemoglobin levels in nonanemic mice, on intratumor oxygenation before and during fractionated irradiation. Furthermore, the consequences of rHuEPO administration on tumor response to fractionated radiotherapy (RT) were evaluated. ⋯ Our results indicate that rHuEPO, by enhancing blood oxygen-carrying capacity, decreases intrinsic tumor hypoxia and maintains its effect during fractionated irradiation in malignant glioma xenografts. Therefore, rHuEPO contributes to radiosensitize these tumors.
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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.
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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.