scholarly journals Comparison of Intensity Modulated Radiotherapy Treatment Plans Between 1.5T MR-Linac and Conventional Linac

2021 ◽  
Vol 20 ◽  
pp. 153303382098587
Author(s):  
Shouliang Ding ◽  
Yongbao Li ◽  
Hongdong Liu ◽  
Rui Li ◽  
Bin Wang ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Current Clinical Practice ◽  
Multiple Tumor ◽  
Dose Volume Histograms ◽  
Intensity Modulated ◽  
Delivery Technique ◽  
Step And Shoot

In this study, we assess the dosimetric qualities and usability of planning for 1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various clinical sites in comparison with IMRT plans using a conventional linac. In total of 30 patients with disease sites in the brain, esophagus, lung, rectum and vertebra were re-planned retrospectively for simulated MRL-IMRT using the Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01). Currently, the step-and-shoot (ss) is the only delivery technique for IMRT available on Unity. All patients were treated on an Elekta Versa HDTM with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was recalculated with the same machine and TPS but only changing the technique to step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformality Index, were compared with the clinical plans. The planning usability was measured by the optimization time and the number of Monitor Units (MUs). Comparing MRL-IMRT with conventional linac based plans, all created plans were clinically equivalent to current clinical practice. However, MRL-IMRT plans had higher dose to skin and larger low dose region of normal tissues. Furthermore, MRL-IMRT plans had significantly reduced optimization time by comparing conventional linac based plans. The number of MUs of MRL-IMRT was increased by 23% compared with ss-IMRT, and no difference from dMLC-IMRT. In conclusion, clinically acceptable plans can be achieved with 1.5 T MR-Linac system for multiple tumor sites. Given the differences in machine characteristics, some minor differences in plan quality were found between MR-Linac plans and current clinical practice and this should be considered in clinical practice.

scholarly journals Comparison of intensity modulated radiotherapy treatment plans between 1.5 T MR-Linac and conventional linac

2020 ◽  
Author(s):  
Shouliang Ding ◽  
Yongbao Li ◽  
Hongdong Liu ◽  
Rui Li ◽  
Bin Wang ◽  
...  
Keyword(s):  
Low Dose ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Conformity Index ◽  
Skin Dose ◽  
Multiple Tumor ◽  
Intensity Modulated ◽  
Delivery Technique ◽  
Step And Shoot

Abstract Background To assess the dosimetric qualities and usability of planning for 1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various clinical sites in comparison with IMRT plans using a conventional linac.Methods In total of 17 patients with disease sites in the brain, esophagus, lung, rectum and vertebra were re-planned retrospectively for simulated MRL-IMRT using the Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01). Currently, the step-and-shoot (ss) is the only delivery technique for IMRT available on Unity. All patients were treated on an Elekta Versa HD™ with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was recalculated with the same machine and TPS but only changing the technique to step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformity Index, were compared with the clinical plans. The planning usability was measured by the optimization time and the number of Monitor Units (MUs).Results Comparing MRL-IMRT with conventional linac based plans, there were no clinically significant differences between any of the DVH parameters studied for multiple tumor sites. However, MRL-IMRT plans had significantly increased dose to skin and low dose region of normal tissue. Furthermore, MRL-IMRT plans had significantly reduced optimization time by comparing conventional linac based plans. The number of MUs of MRL-IMRT was increased by 23% compared with ss-IMRT, and no difference from dMLC-IMRT.Conclusions Clinically acceptable plans can be achieved with 1.5 T MR-Linac system for multiple tumor sites. The planning efficiency of MRL-IMRT was improved due to the reduced optimization time. However the increase in skin dose and low dose region was also observed in MRL-IMRT plans.

scholarly journals Intensity modulated radiotherapy using Monte Carlo for routine postmastectomy radiotherapy

2012 ◽  
Vol 18 (2) ◽  
pp. 49-58
Author(s):  
Hiba Baha Eldin Sayed Omer
Keyword(s):  
Monte Carlo ◽  
Treatment Planning ◽  
Intensity Modulated Radiotherapy ◽  
Response To Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Planning Systems ◽  
Dose Volume Histograms ◽  
Intensity Modulated ◽  
Treatment Planning Systems

Radiotherapy given after mastectomy (PMRT) will reduce the risk of local recurrence by about two-thirds. Clinical and dosimetric trials were carried out using various techniques to optimize the treatments by maximizing the dose to the tumour and minimizing it to the healthy tissues at proximity. Different conventional techniques which have been studied suffer from important dose inhomogeneities due to the complex anatomy of the chest, which reduces the benefits from such treatments. Moreover, due to the heterogeneity of breast cancer, the response to therapy and a systematic approach to treatment cannot be derived and treatment regimens must be determined on a patient-by-patient basis. This is only possible if accurate and fast treatment planning systems are available. Intensity Modulated Radiotherapy (IMRT) allows delivering higher doses to the target volume and limits the doses to the surrounding tissues. The objective of this study is to test the feasibility of applying a Monte Carlo-based treatment planning system, Hyperion accurately in routine Intensity Modulated Radiotherapy (IMRT) postmastectomy. In order to use a treatment planning system for routine work it should prove to provide optimized dose delivery in a suitable time. Treatment planning for IMRT application to PMRT was performed using Hyperion. Constraints were set to deliver the prescribed dose to the target and minimize the dose to the organs at risk. Dose Volume Histograms (DVH) were used to evaluate the set up plans. Time taken to optimize the plan was measured. The target coverage was within the accepted values. Approximately 90% of the breast and 80% of the PTV received 45 Gy or above. The volume of the lung that received 40Gy was less than 10% and the volume that received 20Gy (V20) was less than 25%. The volume of the heart receiving 30 Gy (V30) or above was negligible. This indicates low NTCP of these organs. The time taken for optimization, showed it possible to apply Monte Carlo-based treatment-planning systems for patient-to-patient PMRT.

scholarly journals Monte Carlo-Based Dose Calculation in Postprostatectomy Image-Guided Intensity Modulated Radiotherapy: A Pilot Study

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Ashley Rankine ◽  
Kirsty Turnbull ◽  
Stuart Greenham ◽  
Thomas P. Shakespeare ◽  
Justin Westhuyzen ◽  
...  
Keyword(s):  
Pilot Study ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Dose Calculation ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Step And Shoot

Step-and-shoot (S&S) intensity-modulated radiotherapy (IMRT) using the XiO treatment planning system (TPS) has been routinely used for patients receiving postprostatectomy radiotherapy (PPRT). After installing the Monaco, a pilot study was undertaken with five patients to compare XiO with Monaco (V2.03) TPS for PPRT with respect to plan quality for S&S as well as volumetric-modulated arc therapy (VMAT). Monaco S&S showed higher mean clinical target volume (CTV) coverage (99.85%) than both XiO S&S (97.98%, P = 0.04) and Monaco VMAT (99.44, P = 0.02). Rectal V60Gy volumes were lower for Monaco S&S compared to XiO (46.36% versus 58.06%, P = 0.001) and Monaco VMAT (46.36% versus 54.66%, P = 0.02). Rectal V60Gy volume was lowest for Monaco S&S and superior to XiO (mean 19.89% versus 31.25%, P = 0.02). Rectal V60Gy volumes were lower for Monaco VMAT compared to XiO (21.09% versus 31.25%, P = 0.02). Other organ-at-risk (OAR) parameters were comparable between TPSs. Compared to XiO S&S, Monaco S&S plans had fewer segments (78.6 versus 116.8 segments, P = 0.02), lower total monitor units (MU) (677.6 MU versus 770.7 MU, P = 0.01), and shorter beam-on times (5.7 min versus 7.6 min, P = 0.03). This pilot study suggests that Monaco S&S improves CTV coverage, OAR doses, and planning and treatment times for PPRT.

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 Dosimetric evaluation of cobalt-60 teletherapy in advanced radiation oncology

2018 ◽  
Vol 18 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Manny Mathuthu ◽  
Nhlakanipho Wisdom Mdziniso ◽  
Yihunie Hibstie Asres
Keyword(s):  
Three Dimensional ◽  
Intensity Modulated Radiotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Solid State Drives ◽  
Water Phantom ◽  
Intensity Modulated ◽  
Gafchromic Ebt2 Film ◽  
Ebt2 Film

AbstractBackgroundRecent investigations demonstrate a strong potential for cobalt-60 (Co-60)-based teletherapy. The influence of the lower energy and penetration of a cobalt-60 beam compared with linear accelerator beams is negligible for intensity-modulated radiotherapy.PurposeThe aim of this research is to investigate source head fluence modulation in cobalt-60 teletherapy by using a three-dimensional (3D) physical compensator and secondary collimator jaw motion.Materials and methodsThe Oncentra treatment planning system was used to develop three hypothetical plans by secondary collimator jaw motion. A clinical MDS Nordion Equinox 80 cobalt-60 teletherapy unit was used to acquire conventional water phantom beam characteristics. Fluence modulation experiments were executed at 5·0 cm depth in a PTW universal intensity-modulated radiation therapy (IMRT) verification phantom using calibrated Gafchromic external beam therapy 2 (EBT2) and RTQA2-1010 film batches. Gafchromic EBT2 film was used to sample intensity maps generated by secondary collimator jaw motion, yet Gafchromic RTQA2-1010 film sampled maps from the 3D physical compensator. The solid-state drives used were 75·0 and 74·3 cm for the Gafchromic EBT2 and Gafchromic RTQA2-1010 film measurements.ResultsA 2D gamma index analysis was coded to compare EBT2 film measurements with Digital Imaging and Communications in Medicine data. This analysis was also used to verify film measurements versus Monte-Carlo simulations.ConclusionLateral beam profiles generated from water phantom measurements were used to establish source head fluence modulation on the film measurements. The source head fluence of a cobalt-60 teletherapy beam could be modulated by secondary collimator jaw motion and using a 3D physical compensator.

A dosimetric study of skin toxicity induced by 3-D conventional and intensity-modulated radiotherapy techniques using immobilization mask for treatment of head-and-neck (nasopharyngeal cancer) carcinoma: a prospective study

2018 ◽  
Vol 18 (02) ◽  
pp. 132-137
Author(s):  
Khaldoon Mahmoud Radaideh
Keyword(s):  
Nasopharyngeal Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Skin Toxicity ◽  
Planning System ◽  
Treatment Planning System ◽  
Skin Dose ◽  
Average Percentage ◽  
Intensity Modulated ◽  
Acute Skin Toxicity ◽  
3D Crt

AbstractBackgroundThe purpose of this study was to investigate variations in surface dose, with and without the use of a Klarity® Mask (Orfit Industries America, Wijnegem, Belgium), using intensity-modulated radiotherapy (IMRT) and 3-D conventional radiotherapy (3D-CRT).Materials and methodsThermoluminescent dosimeters (TLDs) together with a phantom were used to examine acute skin toxicity during nasopharyngeal cancer treatment. These plans were sequentially delivered to the perspex phantom. Dosimeters were placed in five fixed regions over the skin. A Klarity mask for immobilization was used for covering the head, neck, and shoulder. The phantom was irradiated with and without a Klarity Mask, using IMRT and 3D-CRT, respectively.ResultsThe Klarity mask increased the skin doses for IMRT and 3D-CRT approximately 18·6% and 8·6%, respectively, from the prescribed maximum skin dose using treatment planning system (TPS). Additionally, the average percentage dose between IMRT and 3D-CRT received on the surface region was 30·9%, 24·9% with and without Klarity mask respectively. The average percentage dose received on surfaces from the total therapeutic dose 70 Gy, without using the mask was 7·7% and 5·7%, for IMRT and 3D-CRT, respectively. The TPS overestimated the skin dose for IMRT planning by 20%, and for 3D-CRT by 16·6%, compared with TLD measurements.ConclusionsThe results of this study revealed that IMRT significantly increases acute skin toxicity, compared with CRT. Although it is recommended to use Klarity mask as a sparing tool of normal tissue, it increases the risk of skin toxicity. In conclusion, skin dose is an important issue of focus during radiotherapy.

scholarly journals Comparison of three film analysis softwares using EBT2 and EBT3 films in radiotherapy

2020 ◽  
Vol 54 (4) ◽  
pp. 505-512
Author(s):  
Tamás Pócza ◽  
Zsuzsánna Zongor ◽  
Barbara Melles-Bencsik ◽  
Dóra Zita Tatai-Szabó ◽  
Tibor Major ◽  
...  
Keyword(s):  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Film Analysis ◽  
Intensity Modulated ◽  
Treatment Techniques ◽  
Passing Rate ◽  
Gamma Analysis ◽  
Software Programs

Abstract Introduction The purpose of the study was to compare the results of gamma value based film analysis according to the used type of self-developer film and software product. Material and methods The films were irradiated with different treatment techniques such as 3D conformal and intensity modulated radiotherapy with static and rotational delivery. Stereotactic plans with conformal and intensity modulated arc techniques, using coplanar and non-coplanar beam setup were also evaluated. The data of irradiated film were compared with the planned planar dose distribution exported from the treatment planning system. Three film analysis software programs were evaluated: PTW Mephysto (PTW), FilmQA Pro (FQP) and radiohromic.com(RC). Both EBT2 and EBT3 types of films were examined. The comparisons of dose distributions were performed with gamma analysis using 10% cut-off level. Results The results of the gamma analysis for larger fields were between 78.3% and 98.3%, 75.7% and 100%, 80.2% and 98.8% with PTW, FQP and RC, respectively. The results of evaluation in case of stereotactic measurements were 76.8%–99.2% for PTW, 95.7%–100% for FQP and 91.2%–99.9% for RC. Conclusions All the three software programs are suitable for calibrating and evaluating films, performing gamma analysis, and can be used for patient specific quality assurance measurements. There is no direct connection between gamma passing rate and absolute accuracy or software quality, it is just a feature of the software. The interpretation of own results has to be defined on an institutional level according to given workflow and preliminary results.

scholarly journals Application of AAPM TG119 to evaluate the Intensity-Modulated radiotherapy (JO-IMRT) plan on the Prowess Panther treatment planning system

2021 ◽  
Vol 5 (2) ◽  
pp. first
Author(s):  
Luong Thi Oanh ◽  
Tai Duong Thanh ◽  
Truong Thi Hong Loan
Keyword(s):  
American Association ◽  
Intensity Modulated Radiotherapy ◽  
Intensity Modulated Radiation Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Test Cases ◽  
Imrt Plan ◽  
Intensity Modulated ◽  
Higher Doses ◽  
3D Crt

Intensity-modulated radiation therapy (IMRT), one of the modern radiotherapy techniques, is one of the most common treatments for cancer. IMRT technique can deliver higher doses to tumor and reduces the minimum dose to normal tissue. Because IMRT technique is more complex than the 3D-CRT techniques, IMRT is potential to underdose the tumor and overdose the nearby critical structures. The American Association of Physicists in Medicine (AAPM) published the TG119 report, including tests and the quality assurance QA process with the aim of to assessing the overall accuracy of planning and delivery of IMRT treatments. The purpose of this research was to study and apply TG119 to evaluate the Prowess Panther planning (TPS) system for JO-IMRT plan at Dong Nai General Hospital with 4 test cases of TG119. Four test cases of TG119 were carried out on the Prowess Panther planning (TPS) system the obtained results were compared to those results of other authors. The results showed that only the prostate plan met 100% of the dose requirements prescribed by TG119, the other plans were relatively appropriate and still met most of the requirements of TG119. From these results, we concluded that Prowess Panther was a good for JO-IMRT.

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