WE-AB-207B-11: Optimizing Tumor Control Probability in Radiation Therapy Treatment - Application to HDR Cervical Cancer

2016 ◽  
Vol 43 (6Part39) ◽  
pp. 3806-3806 ◽  
Author(s):  
E Lee ◽  
F Yuan ◽  
A Templeton ◽  
R Yao ◽  
J Chu
Keyword(s):  
Cervical Cancer ◽  
Radiation Therapy ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Treatment Application ◽  
Therapy Treatment

scholarly journals Investigation of whether in-room CT-based adaptive intracavitary brachytherapy for uterine cervical cancer is robust against interfractional location variations of organs and/or applicators

2016 ◽  
Vol 57 (6) ◽  
pp. 677-683 ◽  
Author(s):  
Yoshifumi Oku ◽  
Hidetaka Arimura ◽  
Tran Thi Thao Nguyen ◽  
Yoshiyuki Hiraki ◽  
Masahiko Toyota ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Radiation Treatment ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
Uterine Cervical Cancer ◽  
Intracavitary Brachytherapy ◽  
Conformity Index ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Target Volumes

Abstract This study investigates whether in-room computed tomography (CT)-based adaptive treatment planning (ATP) is robust against interfractional location variations, namely, interfractional organ motions and/or applicator displacements, in 3D intracavitary brachytherapy (ICBT) for uterine cervical cancer. In ATP, the radiation treatment plans, which have been designed based on planning CT images (and/or MR images) acquired just before the treatments, are adaptively applied for each fraction, taking into account the interfractional location variations. 2D and 3D plans with ATP for 14 patients were simulated for 56 fractions at a prescribed dose of 600 cGy per fraction. The standard deviations (SDs) of location displacements (interfractional location variations) of the target and organs at risk (OARs) with 3D ATP were significantly smaller than those with 2D ATP (P < 0.05). The homogeneity index (HI), conformity index (CI) and tumor control probability (TCP) in 3D ATP were significantly higher for high-risk clinical target volumes than those in 2D ATP. The SDs of the HI, CI, TCP, bladder and rectum D2cc, and the bladder and rectum normal tissue complication probability (NTCP) in 3D ATP were significantly smaller than those in 2D ATP. The results of this study suggest that the interfractional location variations give smaller impacts on the planning evaluation indices in 3D ATP than in 2D ATP. Therefore, the 3D plans with ATP are expected to be robust against interfractional location variations in each treatment fraction.

scholarly journals Radiobiological Evaluation of Dosimetric Plans for Stereotactic Radiotherapy for Prostate Cancer According to Fractionation Regimen

2019 ◽  
Vol 100 (5) ◽  
pp. 263-269
Author(s):  
E. S. Sukhikh ◽  
I. N. Sheyno ◽  
L. G. Sukhikh ◽  
A. V. Taletskiy ◽  
A. V. Vertinskiy ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Total Dose ◽  
Rectal Wall ◽  
Tumor Control ◽  
Anterior Rectal Wall ◽  
Tumor Control Probability ◽  
Equivalent Uniform Dose ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Fractionation Regimen

Objective. To determine the most effective irradiation regimen (total dose and dose per fraction) for hypofractionated treatment for prostate carcinomas according the TCP/NTCP radiobiological criteria.Material and methods. Using the tomographic information of five patients with low-risk prostate adenocarcinoma as an example, the authors devised dosimetric radiation therapy plans using the volumetric modulated arc therapy (VMAT) procedure. They considered the range of total doses of 33.5 to 38 Gy administered in 4 and 5 fractions. Based on the equivalent uniform dose concept proposed by A. Niemierko and on the computed differential dose volume histograms, the investigators modeled local tumor control probability (TCP) values, by taking into account the uncertainties of main radiobiological parameters, and estimated normal tissue complication probabilities (NTCP) for the anterior rectal wall as the organ most at risk of irradiation. An effective dosimetric plan was selected according to the UTCP criterion and the probability of complication-free tumor control, i.e. TCP (1 – NTCP).Results. The results of modeling the UTCP criterion show that with a higher total dose, the TCP value increases and so does the NTCP value, therefore the optimal radiation therapy plans are to irradiate with a total dose of 34 Gy over 4 fractions or with a dose of 36–37 Gy over 5 fractions. The difference between the fractionation regimens is that the UTCP value is achieved with a higher TCP value over 4 fractions and with a lower load on the rectal wall over 5 fractions.Conclusion. The choice of a specific fractionation regimen should be determined from the calculated values of differential dose volume histograms for each patient, as well as from radiobiological criteria, such as TCP, NTCP and UTCP.

Radiobiological Models of Tissue Response to Radiation in Treatment Planning Systems

1998 ◽  
Vol 84 (2) ◽  
pp. 140-143 ◽  
Author(s):  
Andrzej Niemierko
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Three Dimensional ◽  
Tissue Response ◽  
Tumor Control ◽  
Practical Implementation ◽  
Target Cells ◽  
Tumor Control Probability ◽  
Planning Systems ◽  
Treatment Planning Systems

Aims To present several biological concepts and models of tissue response to fractionated radiotherapy. To describe practical implementation of these models in three-dimensional treatment planning systems. Methods Models of cell survival, Equivalent Uniform Dose (EUD) and Tumor Control Probability (TCP) are discussed. These models are based on the target-cell hypothesis which assumes that response of organs and tissues to radiation therapy can be explained and mathematically described in terms of survival of the specific target-cells. Results Several formulae for deriving and calculating EUD and TCP for a given three-dimensional dose distribution are presented and discussed. Conclusions Biological models of tissue response to radiation, when used wisely, have a potential to be useful in radiation therapy treatment planning. The models can advance our understanding of the underlying biological mechanisms, and may help in designing new and better treatment strategies. They should be particularly useful in modern conformai radiotherapy where treatment strategy for each patient can be individualized and optimized according to patient characteristics and available technology of delivering sophisticated treatment plans.

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