scholarly journals The choice of optimal radiotherapy technique for locally advanced maxillary carcinoma using 3d treatment planning system

2004 ◽  
Vol 61 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Dusan Mileusnic
Keyword(s):  
Maxillary Sinus ◽  
Treatment Planning ◽  
Locally Advanced ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Parotid Glands ◽  
3D Conformal Radiotherapy

Aim. To compare the isodose distribution of three radiotherapy techniques for locally advanced maxillary sinus carcinoma and analyze the potential of three-dimensional (3D) conformal radiotherapy planning in order to determine the optimal technique for target dose delivery, and spare uninvolved healthy tissue structures. Methods. Computed tomography (CT) scans of fourteen patients with T3-T4, N0, M0 maxillary sinus carcinoma were acquired and transferred to 3D treatment planning system (3D-TPS). The target volume and uninvolved dose limiting structures were contoured on axial CT slices throughout the volume of interest combining three variants of treatment plans (techniques) for each patient: 1. A conventional two-dimensional (2D) treatment plan with classically shaped one anterior two lateral opposite fields and two types of 3D conformal radiotherapy plans were compared for each patient. 2. Three-dimensional standard (3D-S) plan one anterior + two lateral opposite coplanar fields, which outlines were shaped with multileaf collimator (MLC) according to geometric information based on 3D reconstruction of target volume and organs at risk as seen in the beam eye's view (BEV) projection. 3. Three-dimensional non-standard (3D-NS) plan: one anterior + two lateral noncoplanar fields, which outlines were shaped in the same manner as in 3D-S plans. The planning parameters for target volumes and the degree of neurooptic structures and parotid glands protection were evaluated for all three techniques. Comparison of plans and treatment techniques was assessed by isodose distribution, dose statistics and dose-volume histograms. Results. The most enhanced conformity of the dose delivered to the target volume was achieved with 3D-NS technique, and significant differences were found comparing 3D-NS vs. 2D (Dmax: p<0,05 Daver: p<0,01; Dmin: p<0,05; V90: p<0,05, and V95: p<0,01), as well as 3D-NS vs. 3D-S technique (Dmin: p<0,05; V90: p<0,05, and V95: p<0,01), while there were no differences between 2D vs. 3D-S technique. 3D-S conformal plans were significantly superior to 2D plans regarding the protection of parotid glands, and the additional improvement of dose conformity was achieved with 3D-NS technique. 3D-NS technique resulted in the decrease of Dmax for ipsilateral retina compared with 3D-S technique, while the level of Dmax for optic nerve was increased (within an acceptable range) with 3D-NS technique. Conclusion. In this study, 3D planning of radiotherapy for locally advanced maxillary sinus carcinoma with noncoplanar fields, which number did not exceed the number of fields for conventional arrangement enabled conformal delivering of the adequate dose to the target volume with the improved sparing of adjacent uninvolved healthy tissue structures.

scholarly journals Independent verification of treatment planning system calculations

Nukleonika ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 47-53
Author(s):  
Edyta Dąbrowska-Szewczyk ◽  
Anna Zawadzka ◽  
Beata Brzozowska ◽  
Agnieszka Walewska ◽  
Paweł Kukołowicz
Keyword(s):  
Treatment Planning ◽  
Three Dimensional ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Rank Test ◽  
Average Dose ◽  
Independent Verification ◽  
The Mean

Abstract Purpose According to the available international recommendations, at least one independent verification of the calculations of number of monitor unit (MU) is required for every patient treated by teleradiotherapy. The aim of this study was to estimate the differences of dose distributions calculated with two treatment planning systems: Eclipse (Varian) and Oncentra MasterPlan (Elekta). Materials and methods The analysis was performed for 280 three-dimensional conformal radiotherapy treatment (3D-CRT) plans with photon beams from Varian accelerators: CL 600C/D X6 MV (109 plans), CL 2300C/D X6 MV (43 plans), and CL 2300C/D X15 MV (128 plans). The mean doses in the planning target volume (PTV) and doses at the isocenter point obtained with Eclipse and Oncentra MasterPlan (OMP) were compared with Wilcoxon matched-pairs signed rank test. Additionally, the treatment planning system (TPS) calculations were compared with dosimetric measurements performed in the inhomogeneous phantom. Results Data were analysed for 6 MV plans and for 15 MV plans separately, independently of the treatment machine. The dose values calculated in Eclipse were significantly (p <0.001) higher compared to calculations of OMP system. The average difference of the mean dose to PTV was (1.4 ± 1.0)% for X6 MV and (2.5 ± 0.6)% for X15 MV. Average dose disparities at the isocenter point were (1.3 ± 1.9)% and (2.1 ± 1.0)% for X6 MV and X15 MV beams, respectively. The largest differences were observed in lungs, air cavities, and bone structures. Moreover the variation in dosimetric measurements was less as compared to Eclipse calculations. Conclusions OMP calculations were introduced as the independent MU verification tool with the first action level range equal to 3.5%.

DOSIMETRIC COMPARISON OF VMAT AND 3D CONFORMAL RADIOTHERAPY IN PREOPERATIVE RECTAL CANCER

2021 ◽  
Author(s):  
Tatjana Miladinović ◽  
◽  
Aleksandar Miladinović ◽  
Nina Pavlović ◽  
Dragoslav Nikezić ◽  
...  
Keyword(s):  
Femoral Head ◽  
Treatment Planning ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Rectum Cancer ◽  
Clockwise Direction ◽  
3D Crt

The standard procedure in treating rectum cancer is surgical intervention, but presurgical chemotherapy and radiotherapy lead to a lower rate of localized recidives. Our study compared the results obtained by two techniques of radiation treatment planning (RTP) in radiotherapy, which patients received in the preoperative course of rectum cancer treatment, Volumetric Modulated Arc Therapy (VMAT) and field-in-field three-dimensional conformal radiotherapy (FIF 3D-CRT). We analyzed better coverage of the planning target volume (PTV) and better protection of organs from risk (OAR): bladder, bowel, left femoral head, and right femoral head results and monitor unit (MU). Also, we analyzed the target volume coverage indicators included homogeneity index (HI), and conformity index (CI). Selected five patients were treated in University Clinical Center Kragujevac during 2020. The two types of techniques for making radiotherapy plans, mentioned above, were designed for each patient using the same CT scans. All plans were done on the treatment planning system ECLIPSE- Version 15.6 (Varian). The prescribed dose for all patients was 50 Gy in 25 fractions. The first arc was planned in the clockwise direction and the second in the counter clockwise direction. FIF 3D-CRT plans were obtained by using fields from four different directions with the same isocenter. It was obtained that VMAT plans, compared to the FIF 3D-CRT, achieved better coverage of the PTV (D95%), better heterogeneity, and conformity. Protection for OAR such as the bladder, femoral heads, and small bowel is much better than that given by FIF 3D-CRT plans. However, the number of MU calculated by FIF 3D-CRT is almost twice lower compared to VMAT.

scholarly journals Dosimetric evaluation of a three-dimensional treatment planning system

2011 ◽  
Vol 36 (1) ◽  
pp. 15 ◽  
Author(s):  
Appasamy Murugan ◽  
XavierSidonia Valas ◽  
Kuppusamy Thayalan ◽  
Velayudham Ramasubramanian
Keyword(s):  
Treatment Planning ◽  
Three Dimensional ◽  
Planning System ◽  
Treatment Planning System

The Role of A Conventional Simulator in Multileaf-Plan Simulation: A Proposal

2001 ◽  
Vol 87 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Carlo Capirci ◽  
Polico Cesare ◽  
Giovanni Mandoliti ◽  
Giovanni Pavanato ◽  
Marcello Gava ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Organs At Risk ◽  
Three Dimensional ◽  
Planning System ◽  
Hard Copy ◽  
Treatment Planning System ◽  
Magnification Factor ◽  
Radiographic Images ◽  
Modern Computer

Modern computer networks provide satisfying levels of data recording and verification between the treatment planning system (TPS) and the accelerators, while the main weakness of the preparation chain remains the simulation. When a conventional simulator is employed, it may adversely affect the three-dimensional treatment planning system (3DPS) process because of the difficulty to document the leaf positions on the simulator location films and on the patient's skin. With a conventional simulator, hard copies of the DRRs of each field and CT scans at isocenter level are needed. In an attempt to transfer more information displayed from a BEV perspective from the 3DPS to simulator radiographs, this study aimed to reduce the quality loss by using a 2D conventional simulator in a 3DPS process. We realized an acetate photocopy of TPS data for each field, from a BEV perspective, containing: DRR, wire frames of the PTV, organs at risk and MLC aperture. The photocopies, with an appropriate magnification factor to obtain a correct projective value (ratio 1:1) at isocenter level, are carefully placed on the radiographic images on the same hard copy which allows us to better understand possible setup errors and obliges us to correct these. The method provides reliable documentation, facilitates treatment verification, and fulfils the criteria for MLC simulation. It is accurate, simple, and very inexpensive.

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.

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]

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