scholarly journals DELINEATION OF TARGET VOLUME FOR BRAIN TUMORS IN RADIOTHERAPY USING ACTIVE CONTOUR SEGMENTATION AND SIMPSON INTEGRATION

2020 ◽  
Vol 6 (6) ◽  
pp. 137-145
Author(s):  
Walimatul Fitriyah ◽  
Evi Setiawati ◽  
Kusworo Adi
Keyword(s):  
Brain Tumor ◽  
Active Contour ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Area ◽  
Three Dimension ◽  
Contour Segmentation ◽  
Volume Calculations ◽  
Radio Therapy

This research conducts the delineation process for a brain tumor on the radio therapy. Delineation means the imaging process of target volume that is conducted in the beginning of Treatment Planning System (TPS). Target volume consists of gross tumor volume (GTV), clinical target volume (CTV), planning target volume (PTV), and Organ at Risk (OAR). This research aims to delineate target volume and measure the target volume axial brain tumor. The images that are used are Magnetic Resonance Imaging (MRI) including axial, coronal, and sagittal slice. Evaluation is only done with one patient affected by a brain tumor. Delineation process is performed by the active contour segmentation method and volume calculations using Simpson integration method. The delineation of target volume is conducted by segmenting each slice of images moreover they are reconstructed until the three dimension of visualized target volume is obtained. Having done this process, target area and target volume calculations are conducted. This research results range error rate for target area is 0.0006 to 0.0059 and target volume is 0.0001 to 0.0013

scholarly journals Consistency Study of Multiparametric Magnetic Resonance and Computed Tomography Targeting in Targeted Radiotherapy for Prostate Cancer

2020 ◽  
Author(s):  
Zhen Xu ◽  
Xiao-Dong Li ◽  
Lu Fu ◽  
Yong-Hua Yu
Keyword(s):  
Prostate Cancer ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Organs At Risk ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Area ◽  
Target Delineation ◽  
Significant Difference

Abstract Background: To compare the difference of location by computed tomography (CT) and multiparametric magnetic resonance imaging (mpMRI) on the target delineation and volume for organs at risk (OARs) among patients with prostate cancer. Methods: T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and CT were performed among 11 patients who received radiotherapy for prostate cancer at our center between August 2018 and December 2019. The target areas were delineated using the Eclipse system, and the radiotherapy plans were made based on the treatment planning system (TPS) to compare target volume and dose-volume histogram (DVH) relative to rectum and bladder. Results: The clinical target volume (CTV) of T1WI and T2WI decreased by 18.8% (P=0.001) and 22.72% (P=0.003), respectively, compared with CT. The planning target volume (PTV) on T1WI and T2WI were 20.45% (P=0.015) and 22.31% (P= 0.008) smaller than that defined by CT. There was no significant difference in either CTV or PTV between the areas outlined on T1WI and T2WI. The DVH resulting from CT and MRI comparisons showed that the rectum and bladder dose levels were lower with MRI images compared with CT. It should be noted that at the lateral directions, the range of outlining on T2WI sequence were significantly smaller than others. Conclusion: Target planning based on mpMRI (T1WI, T2WI) is more precise than CT, which can significantly reduce the range of the target area and the volume of rectum and bladder exposed to high levels of radiation, improve the fitness and radiographic accuracy of the target area, especially on T2WI.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

scholarly journals Dosimetric comparison of MR-linac-based IMRT and conventional VMAT treatment plans for prostate cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Vanessa Da Silva Mendes ◽  
Lukas Nierer ◽  
Minglun Li ◽  
Stefanie Corradini ◽  
Michael Reiner ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Target Coverage ◽  
Treatment Delivery ◽  
Ptv Margin ◽  
Delivery Times ◽  
Low Field ◽  
Treatment Plans

Abstract Background The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Materials and methods 20 PCa patients previously treated with conventional VMAT were considered. For each patient, two different IMRT MRL plans using the low-field MR-linac treatment planning system were created: one with original (orig.) PTV margins and the other with reduced (red.) PTV margins. Dose indices related to target coverage, as well as dose-volume histogram (DVH) parameters for the target and organs at risk (OAR) were compared. Additionally, the estimated treatment delivery times and the number of monitor units (MU) of each plan were evaluated. Results The dose distribution in the high dose region and the target volume DVH parameters (D98%, D50%, D2% and V95%) were similar for all three types of treatment plans, with deviations below 1% in most cases. Both IMRT MRL plans (orig. and red. PTV margins) showed similar homogeneity indices (HI), however worse values for the conformity index (CI) were also found when compared to VMAT. The IMRT MRL plans showed similar OAR sparing when the orig. PTV margins were used but a significantly better sparing was feasible when red. PTV margins were applied. Higher number of MU and longer predicted treatment delivery times were seen for both IMRT MRL plans. Conclusions A comparable plan quality between VMAT and IMRT MRL plans was achieved, when applying the same PTV margin. However, online MR-guided adaptive radiotherapy allows for a reduction of PTV margins. With a red. PTV margin, better sparing of the surrounding tissues can be achieved, while maintaining adequate target coverage. Nonetheless, longer treatment delivery times, characteristic for the IMRT technique, have to be expected.

Evaluation of Auto-Planning for Left-Side Breast Cancer After Breast-Conserving Surgery Based on Geometrical Relationship

2020 ◽  
Author(s):  
Yijiang Li ◽  
Han Bai ◽  
Danju Huang ◽  
Feihu Chen ◽  
Xuhong Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Correlation Coefficient ◽  
Dose Distribution ◽  
Breast Conserving Surgery ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Geometric Information ◽  
Ipsilateral Lung ◽  
Geometrical Relationship

Abstract Purpose: This study aimed to evaluate (1) the performance of the Auto-Planning module embedded in the Pinnacle treatment planning system (TPS) with 30 left-side breast cancer plans and (2) the dose-distance correlations between dose-based patients and overlap volume histogram-based (OVH) patients. Method: A total of 30 patients with left-side breast cancer after breast-conserving surgery were enrolled in this study. The clinical manual-planning (MP) and the Auto-Planning (AP) plans were generated by Monaco and by the Auto-Planning module in Pinnacle respectively. The geometric information between organ at risk (OAR) and planning target volume (PTV) of each patient was described by the OVH. The AP and MP plans were ranked to compare with the geometry-based patients from OVH. The Pearson product-moment correlation coefficient (R) was used to describe the correlations between dose-based patients (APs and MPs) and geometry-based patients (OVH). Dosimetric differences between MP and AP plans were evaluated with statistical analysis. Result: The correlation coefficient (mean R = 0.71) indicated that the AP plans have a high correlation with geometry-based patients from OVH, whereas the correlation coefficient (mean R = 0.48) shows a weak correlation between MP plans and geometry-based patients. For different indicators, the dose distribution of V5Gy in the ipsilateral lung (AP: mean R = 0.82; MP: mean R = 0.58) is more relevant to geometry-based patients compared to the dose distribution of in the heart (AP: mean R = 0.4; MP: mean R = 0.19). The dosimetric comparison revealed a statistically significant improvement in ipsilateral lung V5Gy and V10Gy and in the heart V5Gy of AP plans compared to MP plans. Conclusion: The overall results of AP plans were superior to MP plans. The dose distribution in AP plans was more consistent with the distance-dose relationship described by OVH. After eliminating the interference of human factors, the AP was able to provide more stable and objective plans for radiotherapy patients.

Utilising virtual bolus in superficial planning target volume dose optimisation (TomoTherapy): a phantom study

2019 ◽  
Vol 19 (1) ◽  
pp. 65-70
Author(s):  
Gim Chee Ooi ◽  
Iskandar Shahrim Bin Mustafa
Keyword(s):  
Treatment Planning ◽  
Planning Target Volume ◽  
Treatment Plan ◽  
Target Volume ◽  
The Body ◽  
Phantom Study ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Volume Histograms ◽  
Photon Fluence

AbstractAim:This is a phantom study to evaluate the dosimetry effects of using virtual bolus (VB) in TomoTherapy Treatment Planning System (TPS) optimisation for superficial planning target volume (PTV) that extends to the body surface. Without VB, the inverse-planning TPS will continuously boost the photon fluence at the surface of the superficial PTV due to lack of build-up region. VB is used during TPS optimisation only and will not be present in actual treatment delivery.Materials and methods:In this study, a dummy planning target was contoured on a cylindrical phantom which extends to the phantom surface, and VB of various combinations of thickness and density was used in treatment planning optimisation with TomoTherapy TPS. The plans were then delivered with the treatment modality TomoTherapy. Radiochromic films (Gafchromic EBT3) were calibrated and used for dose profiles measurements. TomoTherapy Planned-Adaptive software was used to analyse the delivered Dose-Volume Histograms (DVHs).Results:The use of 2 mm VB was not providing adequate build-up area and was unable to reduce the hot spots during treatment planning and actual delivery. The use of 4 mm VB was able to negate the photon fluence boosting effect by the TPS, and the actual delivery showed relatively small deviations from the treatment plan. The use of 6 mm VB caused significant dose overestimation by the TPS in the superficial regions resulting in insufficient dose coverage delivered.Findings:VB with the combination of 4 mm thickness and 1·0 g/cc density provides the most robust solution for the TomoTherapy TPS optimisation of superficial PTV.

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.

FDG-PET/CT imaging for staging and definition of tumor volumes in radiation treatment planning in non-small cell lung cancer

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7574-7574 ◽  
Author(s):  
Y. Xu ◽  
S. Ma ◽  
D. Yu ◽  
J. Wang ◽  
L. Zhang ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Fdg Pet ◽  
Radiation Treatment ◽  
Target Volume ◽  
Ct Images ◽  
Planning System ◽  
Treatment Planning System ◽  
Volume Delineation ◽  
Pet Ct ◽  
Fdg Pet Ct

7574 Background: 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) /computed tomography (CT) has a potential improvement for staging and radiation treatment (RT) planning of various tumor sites. But from a clinical standpoint, the open questions are essentially the following: to what extent does PET/CT change the target volume? Can PET/CT reduce inter-observer variability in target volume delineation? We analyzed the use of FDG-PET/ CT images for staging and evaluated the impact of FDG- PET/CT on the radiotherapy volume delineation compared with CT in patients with non-small cell lung cancer (NSCLC) candidates for radiotherapy. Intraobserver variation in delineating tumor volumes was also observed. Methods: Twenty-three patients with stage I-III NSCLC were enrolled in this pilot study and were treated with fractionated RT based therapy with or without chemotherapy. FDG-PET/CT scans were acquired within 2 weeks prior to RT. PET and CT data sets were sent to the treatment planning system Pinnacle through compact disc. The CT and PET images were subsequently fused by means of a dedicated radiation treatment planning system. Gross Tumor Volume (GTV) was contoured by four radiation oncologists respectively on CT (CT-GTV) and PET/CT images (PET/CT-GTV). The resulting volumes were analyzed and compared. Results: For the first phase, two radiation oncologists outlined together the contours achieving a final consensus. Based on PET/CT, changes in TNM categories occurred in 8/23 cases (35%). Radiation targeting with fused FDG-PET and CT images resulted in alterations in radiation therapy planning in 12/20 patients (60%) by comparison with CT targeting. The most prominent changes in GTV have been observed in cases with atelectasis. For the second phase was four intraobserver variation in delineating tumor volumes. The mean ratio of largest to smallest CT-based GTV was 2.31 (range 1.01–5.96). The addition of the PET data reduced the mean ratio to 1.46 (range 1.12–2.27). Conclusions: PET/CT fusion images could have a potential impact on both tumor staging and treatment planning. Implementing matched PET/CT reduced observer variation in delineating tumor volumes significantly with respect to CT only. [Table: see text]

scholarly journals Initial Validation of Proton Dose Calculations on SPR Images from DECT in Treatment Planning System

2020 ◽  
Vol 7 (2) ◽  
pp. 51-61
Author(s):  
Sina Mossahebi ◽  
Pouya Sabouri ◽  
Haijian Chen ◽  
Michelle Mundis ◽  
Matthew O'Neil ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Treatment Planning ◽  
Effective Atomic Number ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Relative Electron ◽  
Treatment Plans ◽  
Proton Dose

Abstract Purpose To investigate and quantify the potential benefits associated with the use of stopping-power-ratio (SPR) images created from dual-energy computed tomography (DECT) images for proton dose calculation in a clinical proton treatment planning system (TPS). Materials and Methods The DECT and single-energy computed tomography (SECT) scans obtained for 26 plastic tissue surrogate plugs were placed individually in a tissue-equivalent plastic phantom. Relative-electron density (ρe) and effective atomic number (Zeff) images were reconstructed from the DECT scans and used to create an SPR image set for each plug. Next, the SPR for each plug was measured in a clinical proton beam for comparison of the calculated values in the SPR images. The SPR images and SECTs were then imported into a clinical TPS, and treatment plans were developed consisting of a single field delivering a 10 × 10 × 10-cm3 spread-out Bragg peak to a clinical target volume that contained the plugs. To verify the accuracy of the TPS dose calculated from the SPR images and SECTs, treatment plans were delivered to the phantom containing each plug, and comparisons of point-dose measurements and 2-dimensional γ-analysis were performed. Results For all 26 plugs considered in this study, SPR values for each plug from the SPR images were within 2% agreement with measurements. Additionally, treatment plans developed with the SPR images agreed with the measured point dose to within 2%, whereas a 3% agreement was observed for SECT-based plans. γ-Index pass rates were > 90% for all SECT plans and > 97% for all SPR image–based plans. Conclusion Treatment plans created in a TPS with SPR images obtained from DECT scans are accurate to within guidelines set for validation of clinical treatment plans at our center. The calculated doses from the SPR image–based treatment plans showed better agreement to measured doses than identical plans created with standard SECT scans.

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