Analyzing the association between dose-volume parameters and radiation-induced brain edema in patients with brain tumor receiving stereotactic radiosurgery

2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040134
Author(s):  
Yang-Wei Hsieh ◽  
Chin-Shiuh Shieh ◽  
Tai-Lin Huang ◽  
Shyh-An Yeh ◽  
Yi-Kuan Tseng ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Stereotactic Radiosurgery ◽  
Brain Edema ◽  
Magnetic Resonance Images ◽  
Planning System ◽  
Volume Index ◽  
Treatment Planning System ◽  
Dose Volume ◽  
Study Results ◽  
Radiation Induced

In this paper, three-dimensional images were used to analyze the association between dose-volume parameters and radiation-induced brain edema in patients with a brain tumor after receiving stereotactic radiosurgery (SRS). The computed tomography (CT), magnetic resonance images (MRI) and treatment parameters were transferred through the treatment planning system (Multiplan, version 5.1.3). The correlation between the dose of radiation therapy and brain edema was evaluated by image processing methods, such as image normalization, registration, filtering, segmentation, and feature extraction. The association was evaluated by volume index and intersection index. The study results suggest that the volume receiving radiation dose above 30% of the prescribed dose is highly associated with the brain edema in brain tumor patients after SRS. The small number of patients limits the study. Further investigation with larger populations and long-term epidemiological studies are required.

NOVALIS INTENSITY-MODULATED RADIOSURGERY

Neurosurgery ◽  
2008 ◽  
Vol 62 (suppl_5) ◽  
pp. A2-A10 ◽  
Author(s):  
Randy L. Jensen ◽  
Merideth M. Wendland ◽  
Shyh-Shi Chern ◽  
Dennis C. Shrieve
Keyword(s):  
Magnetic Resonance Imaging ◽  
Optic Nerve ◽  
Magnetic Resonance ◽  
Stereotactic Radiosurgery ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Resonance Imaging ◽  
Dose Volume Histograms ◽  
Intensity Modulated

ABSTRACT OBJECTIVE The Novalis stereotactic radiotherapy system (BrainLAB, Heimstetten, Germany) allows for precise treatment of cranial base tumors with single-fraction radiosurgery. In some cases, however, proximity of the optic nerve and chiasm is a concern. In these cases, intensity-modulated stereotactic radiosurgery (IMRS) can be used to limit the dose to these structures. IMRS planning can be labor intensive, which poses a problem when it is performed on the day of treatment. We describe our methods and results of preprocedure planning for IMRS for patients with lesions in the cavernous sinus or parasellar regions in whom the dose to the optic nerve or chiasm might exceed our acceptable tolerance dose (8 Gy). METHODS Patients whose lesions were more than 4 mm from the optic nerve and chiasm on standard magnetic resonance imaging scans but who were questionable candidates for radiosurgery because of concerns of dose to the optic nerve or chiasm were considered for IMRS. Preprocedure imaging (computed tomography and magnetic resonance imaging) was fused and analyzed using the BrainLAB BrainScan 5.3 treatment planning system. Dynamic conformal arc plans for stereotactic radiosurgery and IMRS were evaluated. Doses to the planning target volume and optic apparatus were assessed by dose-volume histograms and conformality index calculated to characterize the quality of the different plans. When IMRS was used, the preplan allowed for a rapid recalculation on the treatment day, minimizing the time patients were in the head frame before treatment. RESULTS We describe three patients with recurrent pituitary tumors and three with meningiomas. Doses were 1500 to 2000 cGy prescribed to the 80 to 96% isodose line delivered by eight to 22 fields. Tumor volumes ranged from 2.70 to 8.82 cm3 (mean, 5.7 cm3). In five of the six patients, the dynamic conformal arc plan precluded delivery of therapeutic dose without exceeding optic nerve tolerance. On the basis of 95% coverage of target volume, maximum prescription doses of 7.7 to 20.64 Gy were possible with the dynamic conformal arc plans without exceeding 8 Gy to the optic apparatus. IMRS allowed maximum doses of 20 to 31 Gy using the same optic apparatus dose restriction. No complications have occurred, and all tumors have remained stable since treatment (mean follow-up period, 30 mo). CONCLUSION We believe this pretreatment technique streamlines the process for IMRS, allowing for better patient comfort and efficient physician time use.

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.

Use of sector analysis of I-125 permanent prostate brachytherapy to evaluate and compare pre- and postimplant dosimetry.

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 242-242
Author(s):  
Ahamed Badusha Mohamed Yoosuf ◽  
Geraldine Workman ◽  
Monica M O'Toole ◽  
Margaret Straney ◽  
Rejina Verghis ◽  
...  
Keyword(s):  
Rapid Assessment ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
P Value ◽  
Prostate Brachytherapy ◽  
Dose Volume ◽  
Sector Analysis ◽  
Dose Homogeneity ◽  
Dosimetric Analysis

242 Background: To evaluate 12 sector analysis in the assessment and comparison of pre- and post- implant dosimetric parameters during the development of an I-125 prostate brachytherapy (PPB) service. Methods: 50 consecutive men being treated with PPB had dose volume analysis in 12 sectors of their pre implant ultrasound (PIUS) and post implant CT (PICT) data using a Variseed 8.0 treatment planning system. PIUS dosimetry was performed 2 weeks prior to implantation and PICT dosimetry 4 weeks post implant. Individual sectors were created by dividing the cranio-caudal prostate length into 3 equal lengths creating prostate base (PB), midgland (PM) and apex (PA). Each of these volumes was then divided into four axial sectors (right and left anterior, right and left posterior). The planning target volume (PTV), dose to 90% of prostate (D90), prostate volume enclosed by 100% (V100), 150% (V150) and 200% (V200) dose were recorded in each sector on PIUS and PICT. Adjacent sectors on PIUS were assessed for dose-volume homogeneity as were adjacent sectors on PICT. Differences in individual sectors on PIUS and PICT were evaluated. Results: Adjacent sector analysis demonstrated dose homogeneity in all sectors of PIUS and the majority of sectors on PICT. Statistically significant differences between PIUS and PICT were noted in target volume, particularly in PB with PICT >PIUS. When individual sectors on PIUS and PICT were compared, statistically significant differences were noted in the majority of dosimetric parameters. The anterior PB and PM were significantly lower on PICT (p value < 0.001) and significantly higher at the posterior PM and PA (p value < 0.05). These changes were consistent across all analysed parameters. In particular, significant absolute differences in D90 in equivalent sectors on PIUS and PICT were seen. Conclusions: 12 sector analysis allows rapid assessment of PIUS and PICT dose and volume homogeneity. It offers a scientific method of identifying areas of relative over and under dosing on PICT when compared with PIUS providing both clinicians and physicists with a learning tool to refine dosimetric analysis and highlight sectors where implant quality could be improved.

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