International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2003
Unique role of proximal rectal dose in late rectal complications for patients with cervical cancer undergoing high-dose-rate intracavitary brachytherapy.
To investigate the correlation of the radiation dose to the upper rectum, proximal to the International Commission of Radiation Units and Measurements (ICRU) rectal point, with late rectal complications in patients treated with external beam radiotherapy (EBRT) and high-dose-rate (HDR) intracavitary brachytherapy (ICRT) for carcinoma of the uterine cervix. ⋯ Eighty-nine percent of our patients had a maximal rectal dose from ICRT at the proximal rectum instead of the ICRU rectal point. The difference between patients with and without late rectal complications was more prominent for the proximal rectal dose than for the ICRU rectal dose. It is important and useful to contrast the whole rectal wall up to the rectosigmoid junction and to calculate the dose at the proximal rectum for patients undergoing HDR ICRT.
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Recently, low alpha/beta values of 1.2 and 1.5 Gy for prostate tumors have been derived from clinical results of external beam radiotherapy and of permanent implants of (125)I and (103)Pd. In the analyses the contributions of tumor repopulation, and edema as a result of inserting radioactive seeds in the prostate, have been ignored. In this paper we reanalyzed the clinical data and introduced the contribution of repopulation and edema. ⋯ It seems now that the alpha/beta value is low, 3.1-3.9 Gy, but not as low as the 1.2 and 1.5 Gy reported earlier.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2003
In vivo thermoluminescence dosimetry dose verification of transperineal 192Ir high-dose-rate brachytherapy using CT-based planning for the treatment of prostate cancer.
To evaluate the potential of in vivo thermoluminescence dosimetry to estimate the accuracy of dose delivery in conformal high-dose-rate brachytherapy of prostate cancer. ⋯ Experimental results indicate that the proposed method is feasible for dose verification purposes and suggest that dose delivery in transperineal high-dose-rate brachytherapy after CT-based planning can be of acceptable accuracy.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2003
Comparative StudyPotential for reduced toxicity and dose escalation in the treatment of inoperable non-small-cell lung cancer: a comparison of intensity-modulated radiation therapy (IMRT), 3D conformal radiation, and elective nodal irradiation.
To systematically evaluate four different techniques of radiation therapy (RT) used to treat non-small-cell lung cancer and to determine their efficacy in meeting multiple normal-tissue constraints while maximizing tumor coverage and achieving dose escalation. ⋯ The use of 3D-CRT, particul mean dose, and NTCP in node-positive patients. The use of 3D-CRT, particularly with only 3 to 4 beam angles, has the ability to reduce normal-tissue toxicity, but has limited potential for dose escalation beyond the current standard in node-positive patients. IMRT is of limited additional value (compared to 3D-CRT) in node-negative cases, but is beneficial in node-positive cases and in cases with target volumes close to the esophagus. When meeting all normal-tissue constraints in node-positive patients, IMRT can deliver RT doses 25%-30% greater than 3D-CRT and 130%-140% greater than ENI. Whereas the possibility of dose escalation is severely limited with ENI, the potential for pulmonary and esophageal toxicity is clearly increased.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2003
Improvement in relapse-free survival throughout the PSA era in patients with localized prostate cancer treated with definitive radiotherapy: year of treatment an independent predictor of outcome.
In patients treated with radical prostatectomy in the prostate-specific antigen (PSA) era, it has been demonstrated that the year of treatment in the PSA era is associated with better pathologic parameters and outcomes, independently of other well-recognized parameters such as clinical stage, pretreatment PSA level, or Gleason score. The purpose of the present study was to study a similar phenomenon with definitive radiotherapy (RT). ⋯ When controlling for tumor, treatment, and follow-up parameters, the year in which RT was performed was still an independent predictor of outcome, consistent with observations made for radical prostatectomy patients. This indicates a more favorable presentation of localized prostate in current years probably related to a combination of factors such as screening and increased patient awareness leading to earlier diagnosis. Outcome predictions should be based on contemporaneous series.