Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.1.51 (HDR)
 605 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to assess the long-term survival, disease control, and complication rates of high dose rate intracavitary brachytherapy (HDR-ICR) alone or combined with external beam irradiation (HDR-ICR + EBRT) in patients with pathologically involved or close surgical margin in the vagina (Group 1) and recurrent lesions in the vaginal cuff (Group 2) following hysterectomy for cervical carcinoma. In Group 1, 10 patients received HDR-ICR only, and 11 patients received HDR-ICR + EBRT with or without paravaginal shielding. In Group 2, 8 patients received HDR-ICR only, and 11 patients received HDR-ICR + EBRT with or without paravaginal shielding. The HDR-ICR dose per fraction planned at the Apical Vaginal Point was 5-6 Gy per week. In Group 1, the 5-year absolute survival rates (AS), disease-free survival rates (DFS), and vaginal control rates (VC) were 81.0%, 76.2%, and 100%, respectively. The 5-year AS was lower in patients with parametrial infiltration or adenocarcinoma. In Group 2, the 5-year AS, DFS, and VC were 73.3%, 77.4% and 88.8%, respectively. The 5-year AS was lower when tumors were larger than 3 cm or infiltrated. Late complications occurred in 10 patients. In all but one patient, the complications were acceptable. All patients with cystitis, ileus, or leg edema received EBRT + HDR-ICR. We recommend a treatment regimen of 25-30 Gy of HDR-ICR alone for Group 1 patients without pathologically high risk of recurrence or Group 2 patients with superficial recurrent lesions, and a treatment regime of 50 Gy whole pelvis EBRT combined with 10-15 Gy HDR-ICR for Group 1 patients with pathologically high risk of recurrence or Group 2 patients with infiltrated recurrent lesions.
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PMID:High dose rate intracavitary brachytherapy for recurrent or residual lesions in the vaginal cuff: results in post-hysterectomy patients with carcinoma of the cervix. 1128 35

The purpose of our research is to compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the target volume, bladder, rectum, and sigmoid colon in patients with carcinoma of the endometrium treated with high dose rate intracavitary Rotte 'Y' applicator brachytherapy (HDRB). Eleven patients with cancer of the endometrium were treated with CT-compatible HDR intracavitary Rotte 'Y' applicators (Nucletron) and underwent post-implant pelvic CT scans with applicators in place. All patients were treated using orthogonal radiography-based planning. The dose was prescribed to uterine point (a point located 2 cm below the center of a line drawn between the tips of the two ends of the Rotte applicator extending laterally from the tandem by half the maximum uterine width), Point A, and 0.5 cm depth along the upper 3 cm vagina. CT-images were transferred to the PLATO treatment planning system version 14.2.6 and retrospectively planned for volumetric calculations. The clinical target volume (CTV) included the entire uterus, cervix, and upper 3 cm of vagina. The volumes of organs at risk (OAR) were digitized. Dwell positions were identified and registered in both the uterine tandem for each patient. For those receiving HDRB alone, the prescribed dose was 7 Gy x 5 fractions. Patients who were treated following external beam radiation therapy (EBRT) received 4 Gy x 5 fractions. The interfraction interval was 6-8 hours. The DVHs were computed for the CTV, bladder, rectum, and sigmoid colon. To compare doses of OARs, 1.0 cc, 2.0 cc, and 5.0 cc volumes receiving the highest dose were calculated from DVHs. 3D optimization was done to improve target coverage and decrease dose to critical organs and compared with the 2D orthogonal radiograph-based plan. The mean of percentage of prescribed dose +/- S.D to 1 cc, 2 cc, and 5 cc of the OARs of interest were as follows: Rectum 44 +/- 21%, 39 +/- 18%, and 33 +/- 15%; bladder 104 +/- 36%, 91 +/- 31%, and 73.9 +/- 24%; and sigmoid 124 +/- 35%, 109 +/- 30%, and 89 +/- 25%, respectively. The corresponding dose to ICRU 38 bladder and rectal points were 98 +/- 55% and 50.5 +/- 32%, respectively. The mean dose to uterine point and point A were 99 +/- 1.7% and 98 +/- 3%, respectively. The mean CTV volume was 160 +/- 89 cc with the percentage of volume getting 100% and 90% of the dose being 62 +/- 12% and 68 +/- 12% with 2D plan versus 57 +/- 8% and 67 +/- 8.9% with 3D plan. The dose to critical organs were reduced with 3D optimization for rectum, bladder, and sigmoid by 5.6% (p = 0.04), 20.6% (p = 0.02), and 26.8% (p = 0.005), respectively. Compared to the 3-D volume dose, the prescription points overestimated the dose to the target volume. The under-dosing was because of inability of two channel applicator to cover volumes in the region of the cervix and vagina. The dose to sigmoid colon was high and attention should be given to the sigmoid dose at the time of treatment planning. 3D planning helped in reducing the dose to the critical organs without compromising target coverage. Correlations with outcome are needed to better define the role of 3D dosimetry in treatment planning.
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PMID:Comparison of 2D vs. 3D dosimetry for Rotte 'Y' applicator high dose rate brachytherapy for medically inoperable endometrial cancer. 1698 95

Endometrial carcinoma is the most common malignancy arising in the female genital tract. Intracavitary vaginal cuff irradiation may be given alone or with external beam irradiation in patients determined to be at risk for locoregional recurrence. Vaginal cylinders are often used to deliver a brachytherapy dose to the vaginal apex and upper vagina or the entire vaginal surface in the management of postoperative endometrial cancer or cervical cancer. The dose distributions of HDR vaginal cylinders must be evaluated carefully, so that clinical experiences with LDR techniques can be used in guiding optimal use of HDR techniques. The aim of this study was to optimize dose distribution for Gammamed plus vaginal cylinders. Placement of dose optimization points was evaluated for its effect on optimized dose distributions. Two different dose optimization point models were used in this study, namely non-apex (dose optimization points only on periphery of cylinder) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6-cm active length. Thus 13 optimization points were available at the periphery of the cylinder. The coordinates of the points along the curvature depended on the cylinder diameters and were chosen for each cylinder so that four points were distributed evenly in the curvature portion of the cylinder. Diameter of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0-cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. All optimizations in this study were carried for dose of 6 Gy at dose optimization points. For both non-apex and apex models of vaginal cylinders, doses for apex point and three dome points were higher for the apex model compared with the non-apex model. Mean doses to the optimization points for both the cylinder models and all the cylinder diameters were 6 Gy, matching with the prescription dose of 6 Gy. Iterative optimization routine resulted in the highest dose to apex point and dome points. The mean dose for optimization point was 6.01 Gy for iterative optimization and was much higher than 5.74 Gy for geometric and equal times routines. Step size of 1 cm gave the highest dose to the apex point. This step size was superior in terms of mean dose to optimization points. Selection of dose optimization points for the derivation of optimized dose distributions for vaginal cylinders affects the dose distributions.
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PMID:Optimized dose distribution of Gammamed plus vaginal cylinders. 1918 Dec 51