International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2002
Randomized Controlled Trial Multicenter Study Clinical TrialA phase III comparison of radiation therapy with or without recombinant beta-interferon for poor-risk patients with locally advanced non-small-cell lung cancer (RTOG 93-04).
The results of Phase I/II data testing beta-interferon with radiation therapy in a non-small-cell lung cancer population were promising. Based on these data, the Radiation Therapy Oncology Group (RTOG) initiated a Phase III trial to test the efficacy of beta-interferon in poor-risk patients with Stages IIIA and IIIB non-small-cell lung carcinoma. ⋯ This multicenter, controlled Phase III trial failed to confirm the efficacy of Betaseron in patients receiving definitive radiotherapy for locally advanced, nonmetastatic non-small-cell lung cancer. The use of beta-interferon led to greater rates of both acute and late treatment-related toxicity. The RTOG continues to investigate other biologic modifiers that may provide a nontoxic alternative for this poor-risk population.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2002
Clinical TrialRadiation dose-volume effects on growth hormone secretion.
Growth hormone (GH) deficiency is a known consequence of central nervous system irradiation. The relationship between the dose to the hypothalamus and the time to onset of clinically significant GH deficiency is unknown. Conformal radiotherapy (CRT) techniques allow for a more accurate determination of hypothalamic dosimetry. We correlated the dosimetry of the hypothalamus and the peak GH value after CRT in children with localized primary brain tumors. ⋯ The peak GH response within 12 months after CRT depends on hypothalamic dose-volume effects and may be predicted on the basis of a linear model that sums the effects of the entire distribution of dose. The modeled effects may be used to optimize radiotherapy and minimize and treat GH deficiency.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2002
Is uniform target dose possible in IMRT plans in the head and neck?
Various published reports involving intensity-modulated radiotherapy (IMRT) plans developed using automated optimization (inverse planning) have demonstrated highly conformal plans. These reported conformal IMRT plans involve significant target dose inhomogeneity, including both overdosage and underdosage within the target volume. In this study, we demonstrate the development of optimized beamlet IMRT plans that satisfy rigorous dose homogeneity requirements for all target volumes (e.g., +/-5%), while also sparing the parotids and other normal structures. ⋯ Sparing of both parotids in patients receiving bilateral neck radiation can be achieved without compromising strict target dose homogeneity criteria. The geometry of the normal tissue and target anatomy are shown to be the major factor necessary to predict the parotid sparing that will be possible for any particular case.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2002
Dose optimization of fractionated external radiation and high-dose-rate intracavitary brachytherapy for FIGO stage IB uterine cervical carcinoma.
To determine the optimal dose combination scheme of external beam radiotherapy (EBRT) and high-dose-rate (HDR) intracavitary radiation (ICR) for maximizing tumor control while conferring an acceptable late complication rate in the treatment of Stage IB uterine cervical cancer. ⋯ In treating Stage IB carcinoma of the uterine cervix with HDR-ICR, using fractions of 3 Gy, it is crucial to keep the point A BED at
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2002
Dose-effect relationship for cataract induction after single-dose total body irradiation and bone marrow transplantation for acute leukemia.
To determine a dose-effect relationship for cataract induction, the tissue-specific parameter, alpha/beta, and the rate of repair of sublethal damage, mu value, in the linear-quadratic formula have to be known. To obtain these parameters for the human eye lens, a large series of patients treated with different doses and dose rates is required. The data of patients with acute leukemia treated with single-dose total body irradiation (STBI) and bone marrow transplantation (BMT) collected by the European Group for Blood and Marrow Transplantation were analyzed. ⋯ The alpha/beta value of 0.75 Gy and mu value of 0.65 h(-1) found for the eye lens are characteristic for late-responding tissues. The incidence of cataract formation can now be quantified, taking into account the values calculated for alpha/beta and mu, TBI dose, and dose rate. Also, the reduction in cataract incidence as a result of lens dose reduction by eye shielding can be estimated.