International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Development of a semi-automatic alignment tool for accelerated localization of the prostate.
Delivering high dose to prostate with external beam radiation has been shown to improve local tumor control. However, it has to be carefully performed to avoid partial target miss and delivering excessive dose to surrounding normal tissues. One way to achieve safe dose escalation is to precisely localize prostate immediately before daily treatment. Therefore, the radiation can be accurately delivered to the target. Once the prostate position is determined with high confidence, planning target volume (PTV) safety margin might be reduced for further reduction of rectal toxicity. A rapid computed tomography (CT)-based online prostate localization method is presented for this purpose. ⋯ Results show that daily CT extent fitting provides a precise correction of prostate position in terms of CoG. Identifying prostate extents on five axial CT slices at the CT console is less time-consuming compared with daily contouring of the prostate on many slices. Taking advantage of the prostate curvature in the longitudinal direction, this method also eliminates the necessity of identifying prostate base and apex. Therefore, it is clinically feasible and should provide an accelerated localization of the prostate immediately before daily treatment.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Review Meta AnalysisMeta-analysis of dose-fractionation radiotherapy trials for the palliation of painful bone metastases.
To compare pain relief among various dose-fractionation schedules of localized radiotherapy (RT) in the treatment of painful bone metastases. ⋯ Meta-analysis of reported randomized trials shows no significant difference in complete and overall pain relief between single and multifraction palliative RT for bone metastases. No dose-response relationship could be detected by including data from the multifraction vs. multifraction trials. Additional data are needed to evaluate the role of re-irradiation and the impact of RT on other treatment end points such as quality of life.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Procedures for high precision setup verification and correction of lung cancer patients using CT-simulation and digitally reconstructed radiographs (DRR).
In a recent study, large systematic setup errors were detected in patients with lung cancer when a conventional simulation procedure was used to define and mark the treatment isocenter. In the present study, we describe a procedure to omit the session at a conventional simulator to remove simulation errors entirely. Isocenter definition and verification was performed at a computed tomography (CT) simulator, and digitally reconstructed radiographs (DRRs) were used for setup verification and correction at the treatment unit. ⋯ Because the distributions of treatment setup errors measured against DRRs obtained in our CT simulation were equal to previously obtained distributions measured against simulator films, conventional simulation can be omitted and DRRs are well-suited for setup verification. By adopting our CT simulation procedure, the large systematic simulation setup errors, which remain hidden if a conventional simulation is performed, can be avoided.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Megavoltage cone-beam computed tomography using a high-efficiency image receptor.
To develop an image receptor capable of forming high-quality megavoltage CT images using modest radiation doses. ⋯ The acquisition of megavoltage CT images with soft-tissue contrast is possible with irradiations as small as 16 cGy.
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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.