scholarly journals Use Dose Bricks Concept to Implement Nasopharyngeal Carcinoma Treatment Planning

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jia-Ming Wu ◽  
Tsan-Jung Yu ◽  
Shyh-An Yeh ◽  
Pei-Ju Chao ◽  
Chih-Jou Huang ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Total Dose ◽  
Maximum Dose ◽  
Treatment Plan ◽  
Parotid Glands ◽  
Planning Time ◽  
Multileaf Collimators ◽  
Field Edge ◽  
Conformal Treatment ◽  
Left Anterior Oblique

Purpose. A “dose bricks” concept has been used to implement nasopharyngeal carcinoma treatment plan; this method specializes particularly in the case with bell shape nasopharyngeal carcinoma case.Materials and Methods. Five noncoplanar fields were used to accomplish the dose bricks technique treatment plan. These five fields include (a) right superior anterior oblique (RSAO), (b) left superior anterior oblique (LSAO), (c) right anterior oblique (RAO), (d) left anterior oblique (LAO), and (e) superior inferior vertex (SIV). Nondivergence collimator central axis planes were used to create different abutting field edge while normal organs were blocked by multileaf collimators in this technique.Results. The resulting 92% isodose curves encompassed the CTV, while maximum dose was about 115%. Approximately 50% volume of parotid glands obtained 10–15% of total dose and 50% volume of brain obtained less than 20% of total dose. Spinal cord receives only 5% from the scatter dose.Conclusions. Compared with IMRT, the expenditure of planning time and costing, “dose bricks” may after all be accepted as an optional implementation in nasopharyngeal carcinoma conformal treatment plan; furthermore, this method also fits the need of other nonhead and neck lesions if organ sparing and noncoplanar technique can be executed.

scholarly journals Evaluation of Auto-Planning in VMAT for Locally Advaced Nasopharyngeal Carcinoma

2021 ◽  
Author(s):  
Chen Jihong ◽  
Chen Kaiqiang ◽  
Dai Yitao ◽  
Zhang Xiuchun ◽  
Chen Yanyu ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Brain Stem ◽  
Organs At Risk ◽  
Locally Advanced ◽  
Volumetric Modulated Arc Therapy ◽  
Stage Iv ◽  
Optic Chiasm ◽  
Parotid Glands ◽  
Planning Time ◽  
Arc Therapy

Abstract The aim of this study is to demonstrate the feasibility of Auto-Planning module for locally advanced nasopharyngeal carcinoma (NPC). A total of 22 patients with locally advanced NPC were enrolled in this study. For each patient, volumetric modulated arc therapy (VMAT) plans were generated manually by an experienced physicist and automatically by the Auto-Planning module. The dose distribution, dosimetric parameters, monitor units and planning time were compared between automatic plans (APs) and manual plans (MPs). Meanwhile, the overall stage of disease was factored into the evaluation. The targets dose coverage of APs was similar to that of MPs. For most of the organs at risk (OARs) except spial cord, the dose parameters of APs were superior to that of MPs. The Dmax and V50 of brain-stem were statistically decreased by 1.0 Gy and 1.32% respectively, while the Dmax of optic nerves and optic chiasm were also lower in the APs (both P < 0.05). APs provide a similar or superior plan quality to MPs in most cases, except for several patients with stage IV. The dose differences for most OARs were similar between the two types of plans and independent of the overall stage. Nevertheless, the APs provided better brain-stem sparing in patients with stage III, while better the parotid glands sparing in patients with stage IV. Moreover, the monitor units and planning time were significantly decreased in the APs. In general, Auto-Planning was a potential technology on the implementation of VMAT treatment planning for locally advanced NPC.

scholarly journals The influence of the drug LHS-1208 on cardiovascular system

2018 ◽  
Vol 17 (3) ◽  
pp. 70-80
Author(s):  
N. P. Ermakova ◽  
I. V. Merkulova ◽  
O. I. Konyaeva ◽  
N. Yu. Kulbachevskaya ◽  
T. V. Abramova ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Total Dose ◽  
Cardiovascular System ◽  
Anticancer Drug ◽  
Aspartate Aminotransferase ◽  
Heart Muscle ◽  
Maximum Dose ◽  
Morphological Changes ◽  
Toxicological Study ◽  
Functional Changes

Introduction.This article presents a fragment of a preclinical toxicological study of a new Russian anticancer drug derived from n-glycoside indolokarbazole LCS-1208 – study of cardiotoxicity, which is one of the specific complications of anticancer chemotherapy.Objective.Preclinical toxicological study of the effect of the drug LCS-1208 on the cardiovascular system of animals to assess its cardiotoxic effects.Materials and methods.Studies were conducted on 40 healthy non-harmless mongrel male rats and 4 dogs Beagle, male and female. The drug was administered daily 15 times to rats-intraperitoneal in total doses of 50, 100 and 200 mg/kg; to dogs – intravenously in total doses of 20 and 30 mg/kg. The period of observation of rats was 30 days, for dogs was 60 days. Changes in electrocardiogram indices, macroscopic and histological picture of heart changes and changes in biochemical parameters of enzymes activity – lactate dehydrogenase and aspartate aminotransferase were evaluated.Results.In rats LCS-1208 throughout the period of observation caused functional changes in electrocardiogram: increase in PQ and QT intervals and cardiac rhythm disturbance (loss of R wave), which indicates a violation of electrical conductivity. Morphological changes in the heart muscle were detected on the 3rd day of observation in total doses of 100 and 200 mg/kg, which remained until 30 days of observation only in animals receiving the drug in the total dose of 200 mg/kg. In some dogs for different periods of observation the drug caused functional changes in the electrical activity of the heart: an increase in the QRS interval, the inversion of the T wave, the appearance of a deep Q wave and an increase in the activity of lactate dehydrogenase and aspartate aminotransferase compared to back ground indicators. Morphological changes in the heart muscle were detected on the 3rd day of observation only in the total dose of 30 mg/kg, which persisted up to 60 days of observation.Conclusion.It was found that the new Russian anticancer drug LHC-1208, a derivative of indocarbazole N-glycoside, has a cardiotoxic effect, causing functional changes in the cardiovascular system of rats in all doses studied, and in dogs only in the maximum dose. Morphologically, cardiotoxicity is not confirmed in animals receiving a minimal dose of the drug, but only in animals receiving the maximum dose of the drug.

scholarly journals Actual Anatomical and Dosimetric Changes of Parotid Glands in Nasopharyngeal Carcinoma Patients during Intensity Modulated Radiation Therapy

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Gang Ren ◽  
Shou-Ping Xu ◽  
Lei Du ◽  
Lin-Chun Feng ◽  
Bao-Lin Qu ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Nasopharyngeal Carcinoma ◽  
Volume Change ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Parotid Glands ◽  
Intensity Modulated ◽  
Data Comparison ◽  
Clinical Benefits

The goal of this study was to evaluate the actual anatomical and dosimetric changes of parotid glands in nasopharyngeal carcinoma patients during intensity modulated radiation therapy. With helical tomotherapy, its planning system, and adaptive software, weekly anatomical and dosimetric changes of parotid glands in 35 NPC patients were evaluated. Interweekly parotid volume varied significantly (P<0.03). The rate of volume change reached the highest level at the 16th fraction. The averageV1increased by 32.2 (left) and 28.6 (right), and the averageD50increased by 33.9 (left) and 24.93 (right), respectively. Repeat data comparison indicated that theV1andD50varied significantly among different fractions (both withP=0.000). The variation of parotid volume was inversely correlated with that of theV1andD50(both withP=0.000). In conclusion, parotid volume and actual dose vary significantly in NPC patients during IMRT. Replanning at the end of the fourth week of IMRT may have clinical benefits.

scholarly journals Recommendation Regarding the Cranial Upper Border of Level IIb in Delineating Clinical Target Volumes (CTV) for Nasopharyngeal Carcinoma

2020 ◽  
Author(s):  
Lijun Wang ◽  
Shengfu Huang ◽  
Lanfang Zhang ◽  
Xia He ◽  
Yatian Liu
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Lymph Nodes ◽  
Upper Bound ◽  
Stage Iv ◽  
Staging System ◽  
Parotid Glands ◽  
Cervical Lymph Nodes ◽  
Lateral Skull Base ◽  
Target Volumes ◽  
Clinical Target Volumes

Abstract Purpose: To recommend a cranial border for level IIb in delineating clinical target volumes (CTV) for nasopharyngeal carcinoma (NPC) patients receiving intensity-modulated radiotherapy and to help reach a consensus on contouring level IIb in CTV.Methods: From 2012 to 2016, 331 nonmetastatic NPC patients treated with IMRT were retrospectively enrolled. Based on the AJCC 8th staging system of NPC, there were 15 stage I, 76 stage II, 103 stage III, and 137 stage IV patients. The distribution of cervical lymph nodes in NPC was assessed based on imaging. Comparisons of the safety and parotid dose parameters between patients with and without a reduction in the size of level IIb were conducted using SPSS 25.0 and R 2.14.2 software.Results: Metastasis rates in the most commonly involved lymph nodes, the lateral retropharyngeal and IIb nodes, were 82.8% and 64.0%, respectively. Among patients with level IIb involvement, the upper borders of the metastatic nodes were beyond the caudal edge of C1 in 13.7% of cases. The parotid gland D50 and V26 values were significantly reduced after modifying the upper bound of level IIb used to delineate the CTV (P = 0. 000).Conclusion: In principle, the upper bound of level IIb should reach the lateral skull base during delineation of the cervical CTV for NPC. To protect the parotid glands, however, individualized reduction of the upper bound of level IIb is recommended for patients who meet certain criteria.

scholarly journals Acquired resistance of B16 tumor cells to protons after prolonged fractional electron irradiation

2020 ◽  
Vol 29 (4) ◽  
pp. 69-83
Author(s):  
E.E. Beketov ◽  
◽  
E.V. Isaeva ◽  
N.V. Nasedkina ◽  
I.A. Zamulaeva ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Electron Beam ◽  
Total Dose ◽  
Tumor Cells ◽  
Proton Beam ◽  
Phase Distribution ◽  
Clonogenic Assay ◽  
Treatment Plan ◽  
Cycle Phase ◽  
Fractionated Irradiation

Cancer radiotherapy effectiveness largely depends on tumor cells radiosensitivity. Inherent or acquired radioresistance of tumor cells is important challenge in radiation therapy. Response of tumor cells to fractionated radiation therapy has been investigated by many research groups. At present time the use of protons for cancer research and treatment has expanded rapidly. In this connection research on sensitivity of tumor cells to proton beam therapy is an urgent task. The aim of the study was to assess sensitivity of irradiated with electrons or protons B16 melanoma cells to the next electron beam or proton beam irradiation at comparable total doses. Studies with the use of stable tumor cell lines with acquired radioresistance may be useful for the develop-ment of effective treatment plan tailored to the patients with relapses or metastases that have oc-curred after prior unsuccessful radiotherapy with standard types of radiation. Protons were pro-vided by Prometeus installation scanning beam and the electron beam of the accelerator Novac-11. Cells radiosensitivity was measured by clonogenic assay. The resistance of cells first irradiat-ed with protons and electrons to the next irradiation with protons and electrons was estimated by clonogenic assay. DNA damages, cell size, proliferative activity and cell cycle phase distribution were also evaluated. The study demonstrated that fractionated irradiation of B16 cells with elec-trons at the total dose of 60 Gy causes significant reduction of cells radiosensitivity to the next ir-radiation with protons, radiosensitivity of irradiated cells to the second irradiation with electrons remains the same. In contrast, the first fractionated irradiation of cells with protons at the total dose of 50 Gy does not affect the radiosensitivity of the cells to the next irradiation with electrons or protons.

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