International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Significant correlation between rectal DVH and late bleeding in patients treated after radical prostatectomy with conformal or conventional radiotherapy (66.6-70.2 Gy).
Investigating the correlation between dosimetric/clinical parameters and late rectal bleeding in patients treated with adjuvant or salvage radiotherapy after radical prostatectomy. ⋯ DVHs of the rectum are significantly correlated with late bleeding for patients irradiated at 66.6-70.2 Gy after radical prostatectomy.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Biologically effective dose (BED) for interstitial seed implants containing a mixture of radionuclides with different half-lives.
To develop a tool for evaluating interstitial seed implants that contain a mixture of radionuclides with different half-lives and to demonstrate its utility by examining the clinical implications of prescribing to an isodose surface for such an implant. ⋯ Total dose alone is no longer sufficient for a complete characterization of a permanent seed implant containing a mixture of radionuclides with different half-lives due to the presence of cell proliferation and sublethal damage repair in the protracted dose delivery. BED provides a tool for evaluating the radiobiologic effects of mixing different type of radionuclides in the same implant. When radionuclides of different half-lives are mixed in a permanent implant, using the dose prescription established from existing clinical experience of implants with the longer half-life radionuclide would help to avoid radiobiologic "cold" spots.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2003
Probability of late rectal morbidity in 125I prostate brachytherapy.
Rectal toxicity is a concern in prostate brachytherapy because it is difficult to avoid delivering a dose equal to, or greater than, the prescription dose to the anterior surface of the rectum. The purpose of this study was to define the probability that a patient will experience Grade 2 (bleeding/ulceration) late rectal morbidity after 125I prostate brachytherapy according to the rectal dosimetry. ⋯ The percentage of the rectal surface that receives a dose > or =100 Gy is predictive of Grade 2 (bleeding/ulceration) late rectal morbidity after 125I prostate brachytherapy. The probability of late morbidity depends on both the dose and the percentage of the rectal surface that received that dose. Our results indicate that the rectum can tolerate doses of 100, 150, and 200 Gy to approximately 30%, 20%, and 10% of the rectal surface with a < or =5% risk of late morbidity. Our results also indicate that the practical guideline for limiting the incidence of late morbidity to 1%, 3%, or 5% is to keep the maximal rectal dose to <200, 250, and 300 Gy, respectively.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2003
Clinical TrialAccelerated partial breast irradiation using 3D conformal radiation therapy (3D-CRT).
We present a novel three-dimensional conformal radiation therapy (3D-CRT) technique to treat the lumpectomy cavity, plus a 1.5-cm margin, in patients with early-stage breast cancer and study its clinical feasibility. ⋯ Accelerated partial-breast irradiation using 3D-CRT is technically feasible, and acute toxicity to date has been minimal. A CTV-to-PTV margin of 10 mm seems to provide coverage for most patients. However, more patients and additional studies will be needed to validate the accuracy of this margin, and longer follow-up will be needed to assess acute and chronic toxicity, tumor control, and cosmetic results.
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Int. J. Radiat. Oncol. Biol. Phys. · Feb 2003
Predictors of radiation-induced esophageal toxicity in patients with non-small-cell lung cancer treated with three-dimensional conformal radiotherapy.
To evaluate the incidence and clinical/dosimetric predictors of acute and late Radiation Therapy Oncology Group Grade 3-5 esophageal toxicity in patients with non-small-cell lung cancer (NSCLC) treated with definitive three-dimensional conformal radiotherapy (3D-CRT). ⋯ Concurrent chemotherapy and the maximal esophageal point dose were significantly associated with a risk of Grade 3-5 esophageal toxicity in patients with NSCLC treated with high-dose 3D-CRT. In patients who received concurrent chemotherapy, the threshold maximal esophageal point dose for Grade 3-5 esophageal toxicity was 58 Gy. An insufficient number of patients developed Grade 3-5 esophageal toxicity in the absence of chemotherapy to allow a valid statistical analysis of the relationship between the maximal esophageal point dose and esophagitis.