Postoperative Radiation Therapy in Mammary Carcinoma Stage II: Target volume, organs at risk, absorbed dose, time-dose schedule, and dose to organs at risk in a prospective investigation

1979 ◽  
Vol 18 (4) ◽  
pp. 273-281 ◽  
Author(s):  
Å. Arwidi ◽  
K. Aspegren ◽  
N. E. Augustsson ◽  
Lo. Hafström ◽  
A. Norgren ◽  
...  
Keyword(s):  
At Risk ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Absorbed Dose ◽  
Dose Schedule ◽  
Target Volume ◽  
Postoperative Radiation ◽  
Postoperative Radiation Therapy ◽  
Dose Time ◽  
Prospective Investigation

scholarly journals Use of a Head-Tilting Baseplate During Tomotherapy to Shorten the Irradiation Time and Protect the Hippocampus and Lens in Hippocampal Sparing-Whole Brain Radiotherapy

2021 ◽  
Vol 20 ◽  
pp. 153303382098682
Author(s):  
Kosei Miura ◽  
Hiromasa Kurosaki ◽  
Nobuko Utsumi ◽  
Hideyuki Sakurai
Keyword(s):  
At Risk ◽  
Planning Target Volume ◽  
Irradiation Time ◽  
Organs At Risk ◽  
Absorbed Dose ◽  
Whole Brain Radiotherapy ◽  
Target Volume ◽  
Whole Brain ◽  
Brain Radiotherapy ◽  
Hippocampal Sparing

Purpose: The aim of this study is to comparatively examine the possibility of reducing the exposure dose to organs at risk, such as the hippocampus and lens, and improving the dose distribution of the planned target volume with and without the use of a head-tilting base plate in hippocampal-sparing whole-brain radiotherapy using tomotherapy. Methods: Five paired images of planned head computed tomography without and with tilt were analyzed. The hippocampus and planning target volume were contoured according to the RTOG 0933 contouring atlas protocol. The hippocampal zone to be avoided was delineated using a 5-mm margin. The prescribed radiation dose was 30 Gy in 10 fractions. The absorbed dose to planning target volume dose, absorbed dose to the organ at risk, and irradiation time were evaluated. The paired t-test was used to analyze the differences between hippocampal-sparing whole-brain radiotherapy with head tilts and without head tilts. Results: Hippocampal-sparing whole-brain radiotherapy with tilt was not superior in planning target volume doses using the homogeneity index than that without tilt; however, it showed better values, and for Dmean and D2%, the values were closer to 30 Gy. Regarding the hippocampus, dose reduction with tilt was significantly greater at Dmax, Dmean, and Dmin, whereas regarding the lens, it was significantly greater at Dmax and Dmin. The irradiation time was also predominantly shorter. Conclusion: In our study, a tilted hippocampal-sparing whole-brain radiotherapy reduced the irradiation time by >10%. Therefore, our study indicated that hippocampal-sparing whole-brain radiotherapy with tomotherapy should be performed with a tilt. The head-tilting technique might be useful during hippocampal-sparing whole-brain radiotherapy. This method could decrease the radiation exposure time, while sparing healthy organs, including the hippocampus and lens.

scholarly journals Can volumetric modulated arc radiation therapy reduce organ at risk dose in stage 4 sinonasal tumors in dogs treated with boost irradiation?

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0259112
Author(s):  
Valeria Meier ◽  
Felicitas Czichon ◽  
Linda Walsh ◽  
Carla Rohrer Bley
Keyword(s):  
At Risk ◽  
Radiation Therapy ◽  
Degrees Of Freedom ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Normal Tissue Complication Probability ◽  
Lacrimal Glands ◽  
Stage 4

Intensity modulated radiation therapy (IMRT) introduced marked changes to cancer treatment in animals by reducing dose to organs at risk (OAR). As the next technological step, volumetric modulated arc therapy (VMAT) has advantages (increased degrees-of-freedom, faster delivery) compared to fixed-field IMRT. Our objective was to investigate a possible advantage of VMAT over IMRT in terms of lower OAR doses in advanced-disease sinonasal tumors in dogs treated with simultaneously-integrated boost radiotherapy. A retrospective, analytical, observational study design was applied using 10 pre-existing computed tomography datasets on dogs with stage 4 sinonasal tumors. Each dataset was planned with both, 5-field IMRT and 2 arc VMAT with 10x4.83 Gy to the gross tumor volume and 10x4.2 Gy to the planning target volume. Adequate target dose coverage and normal tissue complication probability of brain ≤5% was required. Dose constraints aspired to were D60 <15 Gy for eyes, D2 <35.4 Gy for corneae, and Dmean <20 Gy for lacrimal glands. OAR dose was statistically significantly higher in IMRT plans than in VMAT plans. Median eye D60% was 18.5 Gy (interquartile range (IQR) 17.5) versus 16.1 Gy (IQR 7.4) (p = 0.007), median lacrimal gland dose 21.8 Gy (IQR 20.5) versus 18.6 Gy (IQR 7.0) (p = 0.013), and median cornea D2% 45.5 Gy (IQR 6.8) versus 39.9 Gy (IQR 10.0) (p<0.005) for IMRT versus VMAT plans, respectively. Constraints were met in 21/40 eyes, 7/40 corneae, and 24/40 lacrimal glands. Median delivery time was significantly longer for IMRT plans than for VMAT plans (p<0.01). Based on these results, VMAT plans were found to be superior in sparing doses to eyes, lacrimal glands, corneae. However, not all ocular OAR constraints could be met while ensuring adequate dose coverage and restricting brain toxicity risk for both planning techniques.

scholarly journals Result Analysis Of Treatment Planning System Between 3-Dimensional Conformal Radiation Therapy Technique And Intensity Modulated Radiation Therapy Technique In Nasopharyngeal Cancer Cases

2017 ◽  
Vol 8 (1) ◽  
pp. 29-34
Author(s):  
Nursama Heru Apriantoro ◽  
Bambang Sutrisno Wibowo ◽  
Muhammad Irsal ◽  
Prima Chintya Delsi Kasih
Keyword(s):  
At Risk ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Nasopharyngeal Cancer ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Homogeneity Index ◽  
Therapy Technique ◽  
3D Crt

This study aims to analyze the difference in results between TPS 3D-CRT radiotherapy irradiation technique and IMRT radiotherapy irradiation technique in nasopharyngeal cancer cases based on the doses received by the target volume and organs at risk and results of isodosis curve which include the value of the index conformity and homogeneity index value. Type of this research is quantitative experimental method. As for the population was taken in 10 patients consisting of 5 male and 5 female patients with nasopharyngeal cancer who received radiation therapy with 3D-CRT irradiation technique and IMRT radiation technique. Meaningfully, the results shows that are no difference in the dose received by the target volume, the dose received by organs at risk, and the curve isodose on these two techniques, including index values of conformity and homogeneity index. In conclusion, IMRT radiotherapy irradiation technique for nasopharyngeal cancer is more prioritized than 3DCRT radiotherapy irradiation technique, as the radiotherapy principle can be achieved by using IMRT radiotherapy irradiation technique.

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