scholarly journals Field in Field Technique (FIF) Technique With Intra-fractionally Modulated Junction Shifts for Cranio-spinal Irradiation (FSI) Planning With 3D-CRT.

2021 ◽  
Author(s):  
Shabbir Hussain A. Ali ◽  
Abdul Hafeez ◽  
Hira Nazim ◽  
Rahim Gohar ◽  
Jawaid Mallick
Keyword(s):  
Spinal Cord ◽  
Maximum Dose ◽  
Advanced Technology ◽  
Dose Volume Histogram ◽  
Dose Delivery ◽  
Dose Volume ◽  
Treatment Volume ◽  
Analysis Of Results ◽  
Fraction Dose ◽  
3D Crt

Abstract Background To plan craniospinal irradiation (CSI) with ‘‘field-in-field’’ (FIF) homogenization technique in combination with daily, intra-fractional modulation of the field junctions, to minimize the possibility of spinal cord overdose. Photon-based techniques for CSI may result in dose inhomogeneity within the treatment volume and usually require a weekly manual shift of the field junctions to minimize the possibility of spinal cord overdose. Nowadays FIF technique is used to feather out the dose inhomogeneity caused by multiple fields. We have started using this technique after acquiring advanced technology machines in recent years. Methods and Materials: 16 patients treated with 3D-CRT for CSI were retrospectively chosen for analysis. These patients were treated during 2016–2017. Contouring of PTV and OAR were done and planning done on Eclipse TM TPS (Varian). These patients were planned with Lateral cranio-cervical fields and posterior spinal fields using a forward-planned, FIF technique. Field junctions were automatically modulated and custom-weighted for maximal homogeneity within each treatment fraction. Dose volume histogram (DVH) was used for analysis of results. A corresponding plan without FIF technique was planned and maximum dose at the junction was noted for each patient with both plans and the readings were evaluated. Results Plan inhomogeneity improved with FIF technique. It provided consistent dose delivery during each fraction of treatment across the junctions. The maximum doses calculated at the junction were higher in the CSI plans without FIF compared to those with FIF technique. Conclusion This paper hence proves that FIF technique is better in planning CSI.

scholarly journals Application of dose-volume histogram prediction in biologically related models for nasopharyngeal carcinomas treatment planning

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Wufei Cao ◽  
Yongdong Zhuang ◽  
Lixin Chen ◽  
Xiaowei Liu
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Volume Histogram ◽  
Parotid Glands ◽  
Dose Volume ◽  
Dose Sparing

Abstract Purpose In this study, we employed a gated recurrent unit (GRU)-based recurrent neural network (RNN) using dosimetric information induced by individual beam to predict the dose-volume histogram (DVH) and investigated the feasibility and usefulness of this method in biologically related models for nasopharyngeal carcinomas (NPC) treatment planning. Methods and materials One hundred patients with NPC undergoing volumetric modulated arc therapy (VMAT) between 2018 and 2019 were randomly selected for this study. All the VMAT plans were created using the Monaco treatment planning system (Elekta, Sweden) and clinically approved: > 98% of PGTVnx received the prescribed doses of 70 Gy, > 98% of PGTVnd received the prescribed doses of 66 Gy and > 98% of PCTV received 60 Gy. Of these, the data from 80 patients were used to train the GRU-RNN, and the data from the other 20 patients were used for testing. For each NPC patient, the DVHs of different organs at risk were predicted by a trained GRU-based RNN using the information given by individual conformal beams. Based on the predicted DVHs, the equivalent uniform doses (EUD) were calculated and applied as dose constraints during treatment planning optimization. The regenerated VMAT experimental plans (EPs) were evaluated by comparing them with the clinical plans (CPs). Results For the 20 test patients, the regenerated EPs guided by the GRU-RNN predictive model achieved good consistency relative to the CPs. The EPs showed better consistency in PTV dose distribution and better dose sparing for many organs at risk, and significant differences were found in the maximum/mean doses to the brainstem, brainstem PRV, spinal cord, lenses, temporal lobes, parotid glands and larynx with P-values < 0.05. On average, compared with the CPs, the maximum/mean doses to these OARs were altered by − 3.44 Gy, − 1.94 Gy, − 1.88 Gy, 0.44 Gy, 1.98 Gy, − 1.82 Gy and 2.27 Gy, respectively. In addition, significant differences were also found in brainstem and spinal cord for the dose received by 1 cc volume with 4.11 and 1.67 Gy dose reduction in EPs on average. Conclusion The GRU-RNN-based DVH prediction method was capable of accurate DVH prediction. The regenerated plans guided by the predicted EUDs were not inferior to the manual plans, had better consistency in PTVs and better dose sparing in critical OARs, indicating the usefulness and effectiveness of biologically related model in knowledge-based planning.

scholarly journals Evaluation of dose-volume histogram prediction for organ-at risk and planning target volume based on machine learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sheng xiu Jiao ◽  
Ming li Wang ◽  
Li xin Chen ◽  
Xiao-wei Liu
Keyword(s):  
Rectal Cancer ◽  
Planning Target Volume ◽  
Maximum Dose ◽  
Nasopharyngeal Cancer ◽  
Target Volume ◽  
Dose Volume Histogram ◽  
Dose Volume ◽  
Significant Difference ◽  
Organ At Risk ◽  
Intensity Radiation

AbstractThe purpose of this work is to evaluate the performance of applying patient dosimetric information induced by individual uniform-intensity radiation fields in organ-at risk (OAR) dose-volume histogram (DVH) prediction, and extend to DVH prediction of planning target volume (PTV). Ninety nasopharyngeal cancer intensity-modulated radiation therapy (IMRT) plans and 60 rectal cancer volumetric modulated arc therapy (VMAT) plans were employed in this study. Of these, 20 nasopharyngeal cancer cases and 15 rectal cancer cases were randomly selected as the testing data. The DVH prediction was performed using two methods. One method applied the individual dose-volume histograms (IDVHs) induced by a series of fields with uniform-intensity irradiation and the other method applied the distance-to-target histogram and the conformal-plan-dose-volume histogram (DTH + CPDVH). The determination coefficient R2 and mean absolute error (MAE) were used to evaluate DVH prediction accuracy. The PTV DVH prediction was performed using the IDVHs. The PTV dose coverage was evaluated using D98, D95, D1 and uniformity index (UI). The OAR dose was compared using the maximum dose, V30 and V40. The significance of the results was examined with the Wilcoxon signed rank test. For PTV DVH prediction using IDVHs, the clinical plan and IDVHs prediction method achieved mean UI values of 1.07 and 1.06 for nasopharyngeal cancer, and 1.04 and 1.05 for rectal cancer, respectively. No significant difference was found between the clinical plan results and predicted results using the IDVHs method in achieving PTV dose coverage (D98,D95,D1 and UI) for both nasopharyngeal cancer and rectal cancer (p-values ≥ 0.052). For OAR DVH prediction, no significant difference was found between the IDVHs and DTH + CPDVH methods for the R2, MAE, the maximum dose, V30 and V40 (p-values ≥ 0.087 for all OARs). This work evaluates the performance of dosimetric information of several individual fields with uniform-intensity radiation for DVH prediction, and extends its application to PTV DVH prediction. The results indicated that the IDVHs method is comparable to the DTH + CPDVH method in accurately predicting the OAR DVH. The IDVHs method quantified the input features of the PTV and showed reliable PTV DVH prediction, which is helpful for plan quality evaluation and plan generation.

Differences of Ring Applicator Reconstruction Methods in Brachytherapy

2021 ◽  
Vol 91 (3) ◽  
pp. 46-54
Author(s):  
D. I. Kazlouski ◽  
A. U. Plysheuskaya
Keyword(s):  
Radiation Source ◽  
Ct Images ◽  
Patient Treatment ◽  
Quality Assurance Program ◽  
Reconstruction Method ◽  
Dose Volume Histogram ◽  
Dose Delivery ◽  
Tracking Method ◽  
Reconstruction Methods ◽  
Dose Volume

Purpose: Analysis and comparison of existing reconstruction methods of the ring applicator, as well as the development of reconstruction method that is closest to the actual source path in dosimetric planning using brachytherapy. Material and methods: Evaluation of reconstruction methods was carried out on the basis of CT images, which were used for dosimetric planning of patient treatment. The obtained data on the positioning of the radiation source using X-ray images were transferred to CT images using matrix transformation methods. A method of reconstruction along the source path is proposed, in which the minimum discrepancies in the location of the source positions in comparison with the coordinates of the actual source positions were obtained. For comparison, the reconstruction of the applicator was performed by three different methods: the method using the manufacturer’s applicator libraries, along the source path, and the method proposed above. Results: The results were assessed using a dose-volume histogram. Dose characteristics were selected based on the recommended ICRU Report 89. To assess the presence of the effect of the reconstruction method on the dose characteristics, the Friedman criterion was used. The differences between the doses for different reconstruction methods turned out to be significant (the critical value of the significance level was considered p=0.05). The maximum deviations of the median values of the parameters of the dose-volume histogram were 7.8 % for the “lib” method, 8.6 % for the tracking method, and 7.9 % for the track_new method. We calculated the median values of the deviations of the source positions obtained using the previously described reconstruction methods from the actual stopping positions of the source found experimentally. Conclusion: The use of the proposed reconstruction method track_new increases the accuracy of determining the positions of the stop of the radiation source in the applicator and, as a consequence, the accuracy of dose delivery on the brachytherapy apparatus in comparison with the manual tracking method. The methods used in this study can be used when putting the applicators into clinical use as part of a radiotherapy quality assurance program. The obtained results will be useful to medical physicists if it is necessary to choose a technique for carrying out the reconstruction of the applicator in accordance with the available capabilities and imaging methods and, as a result, will increase the accuracy of dosimetric planning and dose delivery on brachytherapy afterloaders.

scholarly journals Application of Dose-Volume Histogram Prediction in Biologically Related Models for Nasopharyngeal Carcinomas Treatment Planning

2020 ◽  
Author(s):  
Wufei Cao ◽  
Yongdong Zhuang ◽  
Lixin Chen ◽  
Xiaowei Liu
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Treatment Planning ◽  
Organs At Risk ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Volume Histogram ◽  
Parotid Glands ◽  
Dose Volume ◽  
Dose Sparing

Abstract Purpose: In this study, we employed a gated recurrent unit (GRU)-based recurrent neural network (RNN) using dosimetric information induced by individual beam to predict the dose-volume histogram (DVH) and investigated the feasibility and usefulness of this method in biologically related models for nasopharyngeal carcinomas (NPC) treatment planning.Methods and Materials: One hundred patients with NPC undergoing volumetric modulated arc therapy (VMAT) between 2018 and 2019 were randomly selected for this study. All the VMAT plans were created using the Monaco treatment planning system (Elekta, Sweden) and clinically approved: >98% of PGTVnx received the prescribed doses of 70 Gy, >98% of PGTVnd received the prescribed doses of 66 Gy and >98% of PCTV received 60 Gy. Of these, the data from 80 patients were used to train the GRU-RNN, and the data from the other 20 patients were used for testing. For each NPC patient, the DVHs of different organs at risk were predicted by a trained GRU-based RNN using the information given by individual conformal beams. Based on the predicted DVHs, the equivalent uniform doses (EUD) were calculated and applied as dose constraints during treatment planning optimization. The regenerated VMAT experimental plans (EPs) were evaluated by comparing them with the clinical plans (CPs).Results: For the 20 test patients, the regenerated EPs guided by the GRU-RNN predictive model achieved good consistency relative to the CPs. The EPs showed better consistency in PTV dose distribution and better dose sparing for many organs at risk, and significant differences were found in the maximum/mean doses to the brainstem, brainstem PRV, spinal cord, lenses, temporal lobes, parotid glands and larynx with P-values <0.05. On average, compared with the CPs, the maximum/mean doses to these OARs were altered by -3.44 Gy, -1.94 Gy, -1.88 Gy, 0.44 Gy, 1.98 Gy, -1.82 Gy and 2.27 Gy, respectively. In addition, significant differences were also found in brainstem and spinal cord for the dose received by 1cc volume with 4.11 and 1.67 Gy dose reduction in EPs on average.Conclusion: The GRU-RNN-based DVH prediction method was capable of accurate DVH prediction. The regenerated plans guided by the predicted EUDs were not inferior to the manual plans, had better consistency in PTVs and better dose sparing in critical OARs, indicating the usefulness and effectiveness of biologically related model in knowledge-based planning.

scholarly journals Dose–volume histogram analysis and clinical evaluation of knowledge-based plans with manual objective constraints for pharyngeal cancer

2020 ◽  
Vol 61 (3) ◽  
pp. 499-505 ◽  
Author(s):  
Takuya Uehara ◽  
Hajime Monzen ◽  
Mikoto Tamura ◽  
Kazuki Ishikawa ◽  
Hiroshi Doi ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Dose Volume Histogram ◽  
Parotid Glands ◽  
Pharyngeal Cancer ◽  
Knowledge Based ◽  
Dose Volume ◽  
Arc Therapy

Abstract The present study aimed to evaluate whether knowledge-based plans (KBP) from a single optimization could be used clinically, and to compare dose–volume histogram (DVH) parameters and plan quality between KBP with (KBPCONST) and without (KBPORIG) manual objective constraints and clinical manual optimized (CMO) plans for pharyngeal cancer. KBPs were produced from a system trained on clinical plans from 55 patients with pharyngeal cancer who had undergone intensity-modulated radiation therapy or volumetric-modulated arc therapy (VMAT). For another 15 patients, DVH parameters of KBPCONST and KBPORIG from a single optimization were compared with CMO plans with respect to the planning target volume (D98%, D50%, D2%), brainstem maximum dose (Dmax), spinal cord Dmax, parotid gland median and mean dose (Dmed and Dmean), monitor units and modulation complexity score for VMAT. The Dmax of spinal cord and brainstem and the Dmed and Dmean of ipsilateral parotid glands were unacceptably high for KBPORIG, although the KBPCONST DVH parameters met our goal for most patients. KBPCONST and CMO plans produced comparable DVH parameters. The monitor units of KBPCONST were significantly lower than those of the CMO plans (P &lt; 0.001). Dose distribution of the KBPCONST was better than or comparable to that of the CMO plans for 13 (87%) of the 15 patients. In conclusion, KBPORIG was found to be clinically unacceptable, while KBPCONST from a single optimization was comparable or superior to CMO plans for most patients with head and neck cancer.

scholarly journals Dose-volume histogram constrains for small intestine in postoperative transcutaneous radiotherapy of endometrial carcinoma: comparison between conventional and conformal techniques

2013 ◽  
Vol 3 (2) ◽  
pp. 82-87
Author(s):  
Anela Ramić ◽  
Dženita Ljuca ◽  
Goran Marosević
Keyword(s):  
Small Intestine ◽  
Maximum Dose ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Dose Volume Histogram ◽  
Dose Volume ◽  
Clinical Center ◽  
The Difference ◽  
Paired T Test ◽  
Medium Dose

Introduction: The aim of this study was to determine the dose-volume histogram (DVH) constrains of conventional and conformal transcutaneous radiotherapy for small intestine and perform their comparison.Methods: This retrospective-prospective study included patients who were treated for endometrial cancer using conventional transcutaneous radiotherapy at the Department of Radiotherapy Clinic of Oncology,Hematology and Radiotherapy, University Clinical Center Tuzla in the period from 2009 to 2011. The study was performed on patients of all ages suffering from this condition. The study involved 35 patients. DVHparameters which were analyzed are: minimum dose (Dmin), maximum dose (Dmax), medium dose (Daver) of the small intestine, as well as the volume of the small intestine, which is included in 75%, 95% and 100%dose (V33,75Gy, V42,75Gy, V45Gy) expressed in percentages and cubic centimeters of the affected organ. Working hypothesis was tested with paired t test. The difference between the variables at the level of p <0.05 was considered statistically significant.Results: DVH constrains of transcutaneous conformal radiotherapy showed signifi cantly smaller dose contribution on small intestine than DVH parameters of conventional transcutaneous radiotherapy (p<0.0001).Conclusion: The dose contribution on small intestine was signifi cantly lower by planning three-dimensional conformal transcutaneous radiotherapy in comparison to the conventional planning.

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