scholarly journals Investigation of Predictors to Achieve Acceptable Lung Dose in T-Shaped Upper and Middle Esophageal Cancer With IMRT and VMAT

2021 ◽  
Vol 11 ◽  
Author(s):  
Yan Shao ◽  
Hua Chen ◽  
Hao Wang ◽  
Yanhua Duan ◽  
Aihui Feng ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Roc Analysis ◽  
Intensity Modulated Radiation Therapy ◽  
Lung Dose ◽  
Test Analysis ◽  
Arc Therapy ◽  
Cutoff Points ◽  
Dose Limits ◽  
Dose Constraints

PurposeThe purpose of this study is to investigate whether there are predictors and cutoff points that can predict the acceptable lung dose using intensity-modulated radiation therapy (IMRT) and volume-modulated arc therapy (VMAT) in radiotherapy for upper ang middle esophageal cancer.Material and MethodsEighty-two patients with T-shaped upper-middle esophageal cancer (UMEC) were enrolled in this retrospective study. Jaw-tracking IMRT plan (JT-IMRT), full-arc VMAT plan (F-VMAT), and pactial-arc VMAT plan (P-VMAT) were generated for each patient. Dosimetric parameters such as MLD and V20 of total lung were compared among the three plannings. Ten factors such as PCTVinferior length and PCTVinferior length/total lung length were calculated to find the predictors and cutoff points of the predictors. All patients were divided into two groups according to the cutoff points, and the dosimetric differences between the two groups of the three plans were compared. ANOVA, receiver operating characteristic (ROC) analysis, and Mann–Whitney U-test were performed for comparisons between datasets. A p <0.05 was considered statistically significant.ResultThe quality of the targets of the three plannings was comparable. The total lung dose in P-VMAT was significantly lower than that in JT IMRT and F-VMAT. Monitor unit (MU) of F-VMAT and P-VMAT was significantly lower than that of JT IMRT. ROC analysis showed that among JT IMRT, F-VMAT, and P-VMAT, PCTVi-L, and PCTVi-L/TLL had diagnostic power to predict the suitability of RT plans according to lung dose constraints of our department. For JT IMRT, the cutoff points of PCTVi-L and PCTVi-L/TLL were 16.6 and 0.59. For F-VMAT, the cutoff points of PCTVi-L and PCTVi-L/TLL were 16.75 and 0.62. For P-VMAT, the cutoff points of PCTVi-L and PCTVi-L/TLL were 15.15 and 0.59. After Mann–Whitney U-test analysis, it was found that among the three plannings, the group with lower PCTVi-L and PCTVi-L/TLL could significantly reduce the dose of total lung and heart (p <0.05).ConclusionPCTVi-L <16.6 and PCTVi-L/TLL <0.59 for JT IMRT, PCTVi-L <16.75 and PCTVi-L/TLL <0.62 for F-VMAT and PCTVi-L <15.15, and PCTVi-L/TLL <0.59 for P-VMAT can predict whether patients with T-shaped UMEC can meet the lung dose limits of our department.

Dosimetric study of 3-dimensional conformal radiotherapy, electronic compensator technique, intensity modulated radiation therapy, and volumetric arc therapy in whole-breast irradiation.

2015 ◽  
Vol 33 (28_suppl) ◽  
pp. 44-44
Author(s):  
Chonnipa Nantavithya
Keyword(s):  
Intensity Modulated Radiation Therapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Contralateral Breast ◽  
Breast Irradiation ◽  
Lung Dose ◽  
Volumetric Arc Therapy ◽  
Arc Therapy ◽  
Ct Simulation ◽  
3D Crt

44 Background: Whole breast irradiation is an essential treatment after breast conserving surgery (BCS). Adverse effects are from inhomogeneity of PTV and excessive dose to normal tissues. Aim of this study is to compare dosimetry among standard technique, three-dimensional Conformal Radiotherapy (3D-CRT) and advanced techniques, Electronic Compensator (ECOMP), Intensity Modulated Radiation Therapy (IMRT) and Volumetric Arc Therapy (VMAT). Methods: Images from CT simulation of patients who underwent BCS were replanned. Clinical Target Volume (CTV) was contoured followed RTOG atlas as breast only and breast with chest wall respectively. Planning Target Volume (PTV) was expanded 0.7 cm from CTV. Each patient was replanned with all four techniques. Dose prescription was 50 Gy in 25 fractions. Results: Twenty five patients underwent CT simulation from November 2013 to November 2014 were included. Six patients with node positive were planned for breast with chest wall irradiation and 19 patients with node negative were planned for breast only irradiation. Primary outcome, homogeneity index (HI) of 3D-CRT, ECOMP, IMRT and VMAT were 0.865, 0.889, 0.890 and 0.866 respectively which ECOMP and IMRT were significant higher than 3D-CRT (p values < 0.001). Secondary outcome, conformity index (CI), Mean heart dose (MHD), heart V25, heart V30, mean lung dose (MLD), mean ipsilaterallung dose (MILD), mean contralateral lung dose (MCLD) and mean contralateral breast dose (MCBD) of advanced techniques were significant better than 3D-CRT technique. Conclusions: HI of ECOMP and IMRT were statistically significant higher compared with 3D-CRT technique. Advanced techniques showed statistically significant superior in CI dose to heart, lungs and contralateral breast.

KAMPÜS İÇİ ULAŞIMDA ALTERNATİF SEÇİMLER: KARABÜK ÜNİVERSİTESİ ÖRNEĞİ

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Rukiye Tekin ◽  
Metin Kılıç
Keyword(s):  
Quality Of Life ◽  
Economic Structure ◽  
Survey Study ◽  
City Image ◽  
Test Analysis ◽  
Level Of Education ◽  
University Campuses ◽  
Effective Administration ◽  
Demographic Features

The contribution of universities to economic structure, social and physical insfrastructure, the quality of life and city, and the level of education cannot be regarded. Therefore, it should be provided that university campuses should be areas which reflect city image with their physical structures. In this regard, the effective administration, usage, and development of universities, and the coordination between the units of universities should also be provided. One of the most significant elements of this coordination and cooperation is on campus transportation. One of the main purposes of the thesis is to evaluate inner campus transportation which is the sub-unit of city transportation. Other purposes are to determine the reasons of the perception of the users in reference to their demographic features on campus transportation and the reasons of their preferences of a particular transportation option. A survey study has been conducted in order to measure inner campus transportation perceptions. In this regard, 1112 questionnaire forms have been analysed by the software programme of SPSS. Expression analysis of the reliability, frequency distribution and factors are obtained, and differences were identified by ANOVA and T-TEST analysis.

scholarly journals A Pilot Study of Safer Radiation Dosage to the Heart and Its Subregions

Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 320
Author(s):  
Rita Steponavičienė ◽  
Justinas Jonušas ◽  
Romualdas Griškevičius ◽  
Jonas Venius ◽  
Saulius Cicėnas
Keyword(s):  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Early Death ◽  
Average Dose ◽  
Planning Stage ◽  
Logistic Regression Models ◽  
Dose Volume Histograms ◽  
Critical Dose ◽  
Dosimetric Analysis ◽  
Dose Constraints

Background and Objectives: The real impact of ionizing radiation on the heart and poorer overall survival for patients with non small cell lung cancer (NSCLC) remains unclear. This study aims to determine the safe dose constraints to the heart’s subregions that could prevent patients’ early non-cancerous death and improve their quality of life. Methods and Materials: A retrospective cohort study was performed containing 51 consecutive patients diagnosed with stage III NSCLC and treated using 3D, Intensity-modulated radiation therapy (IMRT), and Volumetric modulated arc therapy (VMAT) radiotherapy. For a dosimetric analysis, these structures were chosen: heart, heart base (HB), and region of great blood vessels (GBV). Dose–volume histograms (DVH) were recorded for all mentioned structures. Maximum and mean doses to the heart, HB, the muscle mass of the HB, and GBV were obtained. V10–V60 (%) parameters were calculated from the DVH. After performed statistical analysis, logistic regression models were created, and critical doses calculated. Results: The critical dose for developing a fatal endpoint for HB was 30.5 Gy, while for GBV, it was 46.3 Gy. Increasing the average dose to the HB or GBV by 1 Gy from the critical dose further increases the possibility of early death by 22.0% and 15.8%, respectively. Conclusions: We suggest that the non-canonical sub-regions of the heart (HB and GBV) should be considered during the planning stage. Additional constraints of the heart subregions should be chosen accordingly, and we propose that the mean doses to these regions be 30.5 Gy and 46.3 Gy, respectively, or less. Extrapolated DVH curves for both regions may be used during the planning stage with care.

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