scholarly journals Evaluation of various common prostate IMRT techniques based on estimated tumor control and normal tissue complication probabilities in correlation with patients anatomical parameters derived from the CT scans

2019 ◽  
Vol 25 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Amin Banaei ◽  
Bijan Hashemi ◽  
Mohsen Bakhshandeh ◽  
Bahram Mofid
Keyword(s):  
Normal Tissue ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
Ct Scans ◽  
Tumor Control ◽  
P Value ◽  
Target Tissue ◽  
Tumor Control Probability ◽  
Radiobiological Effects ◽  
Anatomical Parameters

Abstract Background: The relationship between the prostate IMRT techniques and patients anatomical parameters has been rarely investigated. Objective: to evaluate various prostate IMRT techniques based on tumor control and normal tissue complication probability (TCP and NTCP) values and also the correlation of such techniques with patients anatomical parameters. Methods: Four IMRT techniques (9, 7 and 5 fields and also automatic) were planned on the CT scans of 63 prostate cancer patients. The sum of distances between the organs at risk (OARs) and target tissue and also their average joint volumes were measured and assumed as anatomical parameters. Selected dosimetric and radiobiological parameters (TCP and NTCP) values were compared among various techniques and the correlation with the above anatomical parameters were assessed using Pearsons’ correlation. Results: High correlations were found between the dosimetric/radiobiological parameters of OARs with the joint volumes and with the distances between the OARs and target tissue in all the techniques. The TCP and complication free tumor control probability (P+) values were decreased with increasing the joint volume and decreasing the distances between the OARs and target tissue (as poly-nominal functions). The NTCP values were increased with increasing the joint volumes and decreasing the distances (3-degree poly-nominal functions). For the low percent joint volumes (<20%) and high distances (>7 cm), The TCP, NTCP and P+ showed no statistical differences between various techniques (P-value>0.07). However, 9 and 7 fields techniques indicated better radiobiological results (P-value<0.05) in almost other ranges (>20% joint volumes and <7 cm distances). Conclusion: Based on our results, it would be possible to compare radiobiological effects of various common IMRT techniques and choose the best one regarding to patients anatomical parameters derived from the CT scans.

scholarly journals Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) in Mono and Dual-isocentric Techniques of Breast Cancer Radiation Therapy

2021 ◽  
pp. 192-202
Author(s):  
Kaveh Shirani Tak Abi ◽  
Sediqeh Habibian ◽  
Marzieh Salimi ◽  
Ahmad Shakeri ◽  
Mohammad Mehdi Mojahed ◽  
...  
Keyword(s):  
Breast Cancer ◽  
At Risk ◽  
Radiation Therapy ◽  
Normal Tissue ◽  
Maximum Dose ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
The Other ◽  
Tumor Control ◽  
Tumor Control Probability

Background: Nowadays, radiation therapy plays an important role in the treatment of breast cancer. The important point is the optimal control of the tumor along with the protection of organs at risk. This study aims to investigate and compare the radiobiological factors of the tumor and organs at risk in two different radiation therapy techniques of breast cancer.Methods: Ten left-sided breast cancer patients with breast-conservative surgery were selected for this study. Three-dimensional treatment planning was performed using CT scan images of the patients using PCRT 3D software. Two different tangential external beam techniques were compared: first, dual-isocentric technique (DIT) with two isocentre, one on the breast tissue, and the other one on the supraclavicular lymph nodes and second, a mono-isocentric technique (MIT) with one isocentre at the intersection of the tangential and the supraclavicular field. The total prescribed dose was 5000 cGy per 25 fractions. Dose-volume histograms (DVHs), Tumor control probability (TCP), and normal tissue complication probability (NTCP) curves were used to compare the dosimetric and radiobiological parameters of the tissues in the prementioned techniques. Results: The results showed that the maximum doses in planning target volume (PTV) with mean values of 109% and 110% in the SI and DIT were not significantly different in both techniques and that they were indeed at the optimum level based on the RTOG 1005 protocol. The dose homogeneity index in MMIT was more than that in DIT, while the conformity index and the mean TCP did not show a significant difference in the two techniques. Furthermore, minimum, mean, and maximum dose in the lung and the probability of pneumonitis decreased in MIT. On the other hand, the maximum dose, the dose of 33%, 66%, and 100% of the heart, and the probability of pericarditis in MIT were lower than the figure in DIT. Conclusion: Due to the absence of hot spots at the intersection of tangential and supraclavicular fields and the reduction of mechanical movements of the coach and collimator in MIT, the superiority of this method was confirmed.

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 &lt; 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 Evaluation of the radiobiological gamma index with motion interplay in tangential IMRT breast treatment

2016 ◽  
Vol 57 (6) ◽  
pp. 691-701 ◽  
Author(s):  
Iori Sumida ◽  
Hajime Yamaguchi ◽  
Indra J. Das ◽  
Hisao Kizaki ◽  
Keiko Aboshi ◽  
...  
Keyword(s):  
Early Stage ◽  
Organs At Risk ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Normal Tissue Complication Probability ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Equivalent Uniform Dose ◽  
Gamma Index ◽  
The Impact

Abstract The purpose of this study was to evaluate the impact of the motion interplay effect in early-stage left-sided breast cancer intensity-modulated radiation therapy (IMRT), incorporating the radiobiological gamma index (RGI). The IMRT dosimetry for various breathing amplitudes and cycles was investigated in 10 patients. The predicted dose was calculated using the convolution of segmented measured doses. The physical gamma index (PGI) of the planning target volume (PTV) and the organs at risk (OAR) was calculated by comparing the original with the predicted dose distributions. The RGI was calculated from the PGI using the tumor control probability (TCP) and the normal tissue complication probability (NTCP). The predicted mean dose and the generalized equivalent uniform dose (gEUD) to the target with various breathing amplitudes were lower than the original dose (P &lt; 0.01). The predicted mean dose and gEUD to the OARs with motion were higher than for the original dose to the OARs (P &lt; 0.01). However, the predicted data did not differ significantly between the various breathing cycles for either the PTV or the OARs. The mean RGI gamma passing rate for the PTV was higher than that for the PGI (P &lt; 0.01), and for OARs, the RGI values were higher than those for the PGI (P &lt; 0.01). The gamma passing rates of the RGI for the target and the OARs other than the contralateral lung differed significantly from those of the PGI under organ motion. Provided an NTCP value &lt;0.05 is considered acceptable, it may be possible, by taking breathing motion into consideration, to escalate the dose to achieve the PTV coverage without compromising the TCP.

scholarly journals Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Taiki Magome ◽  
Hidetaka Arimura ◽  
Yoshiyuki Shioyama ◽  
Katsumasa Nakamura ◽  
Hiroshi Honda ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Stereotactic Body Radiotherapy ◽  
Similar Case ◽  
Organs At Risk ◽  
Normal Tissue Complication Probability ◽  
Radiation Absorption ◽  
Conformity Index ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Case Based

Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners.Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP).Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences (P<0.05) in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung.Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT.

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