scholarly journals Comparison of Dosimetric Gains Provided by Intensity-Modulated Radiotherapy, Volume-Modulated Arc Therapy, and Helical Tomotherapy for High-Grade Glioma

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Pei Liu ◽  
Gui Liu ◽  
Guihua Wang ◽  
Weibing Zhou ◽  
Yangqing Sun ◽  
...  
Keyword(s):  
At Risk ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiotherapy ◽  
High Grade Glioma ◽  
The Other ◽  
Planning System ◽  
Treatment Planning System ◽  
High Grade ◽  
Intensity Modulated ◽  
Arc Therapy

Purpose. Because of the poor prognosis for high-grade glioma (HGG) patients, it is important to increase the dose of the tumor to improve the efficacy while minimizing the dose of organs at risk (OARs). Thus, we evaluated the potential dosimetric gains of helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT) or volume-modulated arc therapy (VMAT) for high-grade glioma (HGG). Methods. A total of 42 HGG patients were retrospectively selected who had undergone helical tomotherapy; then, IMRT and VMAT plans were generated and optimized for comparison after contouring crucial neuronal structures for neurogenesis and neurocognitive function. IMRT and VMAT were optimized with the Eclipse treatment planning system (TPS) (Version 11.0.31) and HT using TomoTherapy Hi-Art Software (Version 2.0.7) (Accuray, Madison, WI, USA). All three techniques were optimized for simultaneously delivering 60 Gy to planning target volume (PTV) 1 and 50-54 Gy to PTV2. We also analyzed the homogeneity index (HI) and conformity index (CI) of PTVs and organ at risk (OAR) sparing. Results. There was no significant difference in the PTV coverage among IMRT, VMAT, or HT. As for the HI, HT plans (PTV1 HI: 0.09±0.03, PTV2 HI: 0.17±0.05) had the best homogeneity when compared to IMRT plans (PTV1 HI: 0.10±0.04, PTV2 HI: 0.18±0.04) and VMAT plans (PTV1 HI: 0.11±0.03, PTV2 HI: 0.20±0.03). The CI value of HT (PTV1 CI: 0.98±0.03, PTV2: 0.98±0.05) was closest to the optimal value. Except for the IMRT and VMAT groups, there were statistically significant differences between the other two groups of the CI values in both PTV1 and PTV2. The other comparison values were statistically significant except for the optic nerve, and VMAT had the best sparing of the optic chiasm. The mean and max doses of OARs declined significantly in HT. Conclusions. For high-grade glioma patients, HT had superior outcomes in terms of PTV coverage and OAR sparing as compared with IMRT/VMAT.

Dosimetric Comparison of Static Intensity Modulated Radiotherapy, Dynamic Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Thoracic Esophageal Cancer: A Single Institutional Experience

2020 ◽  
Vol 10 (3) ◽  
pp. 628-632
Author(s):  
Ruihao Wang ◽  
Qingxing Zeng ◽  
Songgui Luo ◽  
Guohui Shen ◽  
Ping Li ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Statistical Significance ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Thoracic Esophageal Cancer ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
Delivery Efficiency

The aim of this study was to evaluate the dosimetric variations of static intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiotherapy (dIMRT) and volumetric modulated arc therapy (VMAT) for thoracic esophageal cancer (EC). Ten patients with pathologically-confirmed EC were randomly selected. The Monaco 5.11 treatment planning system was used to design six radiotherapy plans, namely sIMRT with 5 fixedfields (S5) and 7 fixed-fields (S7), dIMRT with 5 fixed-fields (D5) and 7 fixed-fields (D7) and VMAT plan with single arc (VMAT1) and double arc (VMAT2), respectively. The dosimetric parameters were compared among six different plans. The dose to target volumes met the clinical prescription requirements in all six plans. The D5 plan had the lowest dose exposed to the whole lungs, except for V5, which was only 1.7% higher than that in the D7 plan. The low dose to lungs (V5 and V10) in VMAT plans (VMAT1 and VMAT2) were higher than in IMRT plans, but the statistical differences were significant (P < 0.05) only in comparison with dynamic IMRT plans (D5 and D7). The V20 and V30 of lungs in VMAT2 plan were also higher than that in other plans, but the statistical differences were significant (P < 0.05) only in comparison with D5 plan. The doses delivered to the spinal cord and heart showed no statistical significance (P > 0.05). The monitor units (MUs) and treatment time (TT) significantly increased with the increasing number of fields in the same kind of fixed-fields IMRT plans (S5 vs. S7; D5 vs. D7). The MUs in VMAT plans, especially in VMAT2, increased significantly (P < 0.05) when compared with sIMRT and 5-fields dIMRT plans, respectively. VMAT1 plan had the shortest TT and the highest delivery efficiency. For thoracic esophageal cancer, the D5 plan can shorten the TT and improve the delivery efficiency while meeting the dosimetric requirements and sparing the lungs. VMAT can significantly reduce the TT, but at the expense of increasing the dose to lower-dose regions of lungs, which means VMAT plan may not shows obvious dose advantage for thoracic esophageal cancer.

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.

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.

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