International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Radiotherapy alone in the treatment of uterine cervix cancer with telecobalt and low-dose-rate brachytherapy: retrospective analysis of results and variables.
This retrospective analysis aims to report results and variables from patients with cervix cancer treated by radiation therapy alone with telecobalt and low-dose-rate brachytherapy (LDRB). ⋯ Results of this series suggest that the use of telecobalt equipment for EBR with doses up to 50 Gy at whole pelvis, prior to brachytherapy, is an acceptable technique for radiation therapy alone in the treatment of cervix cancer, especially in developing countries, including Brazil, where telecobalt machines still prevail.
-
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.
-
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.
-
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.
-
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.