scholarly journals The impact of leaf width and plan complexity on DMLC tracking of prostate intensity modulated arc therapy

2013 ◽  
Vol 40 (11) ◽  
pp. 111717 ◽  
Author(s):  
Tobias Pommer ◽  
Marianne Falk ◽  
Per Rugaard Poulsen ◽  
Paul J. Keall ◽  
Ricky T. O’Brien ◽  
...  
Keyword(s):  
Leaf Width ◽  
Intensity Modulated ◽  
Arc Therapy ◽  
The Impact

Choice of appropriate beam model and gantry rotational angle for low-dose gradient-based craniospinal irradiation using volumetric-modulated arc therapy

2016 ◽  
Vol 16 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Biplab Sarkar ◽  
Anirudh Pradhan
Keyword(s):  
Low Dose ◽  
Volumetric Modulated Arc Therapy ◽  
Craniospinal Irradiation ◽  
Leaf Width ◽  
Beam Model ◽  
Significant Difference ◽  
Arc Therapy ◽  
Prescription Dose ◽  
Flat Beam ◽  
The Impact

AbstractObjectivesWe aimed to assess the impact of advanced multileaf collimator (MLC) models and flattening filter-free (3F) beam in volumetric-modulated arc therapy (VMAT)-based craniospinal irradiation (CSI).MethodsCT scans of five medulloblastoma patients who previously received CSI at our hospital were used for the present study. Patients were planned for a prescription dose of 35 Gy to craniospinal axis. A three-dimensional conformal radiotherapy (3DCRT) plan and a VMAT plan using 1 cm MLC leaf width were generated as the gold standard (reference arm). Test VMAT plans were generated using Agility MLC model (MLC leaf width 5 mm) for various combinations of flattened beam (F) and 3F beam for treating the brain and spine planning target volume (PTV). Organs at risks (OARs) were analysed for dose 5, 50, 75 and 90% volumes, mean dose and maximum dose.ResultsAll 3DCRT plans and VMAT plans were aimed to cover 95% of PTV by at least 95% prescription dose. VMAT demonstrated lesser dose spillage than 3DCRT to body volume minus PTV (NTID: non tumor integral dose) for a dose threshold above 7·5 Gy. For the low-dose range (1–7 Gy), variation between the dose coverage between all VMAT plans (for either spine or brain PTV) was <1%. Intra-VMAT plan dose variation for all OAR’s for all tested parameters was <1 Gy. Average monitor unit (MU) difference among different VMAT plans ranged between 1·52 and 2·13 when normalised to 3DCRT MU. For VMAT plans, flat beam with 1 cm MLC showed the highest MU, whereas Agility MLC with 3F beam had the least MU values for intra-VMAT plans. No statistical significance variation (p) was observed in between reference arm and test arm plans except for mean dose and V107% for PTV spine. When compared between reference arm 3DCRT and test arm VMAT plans. For OAR’s, no statistical difference was observed between reference and test arm VMAT plans.ConclusionsReference arm plans and test arm plans exhibit no statistically significant difference. However, as compared with 3DCRT, VMAT plans are more conformal and produce lesser dose to OAR at the cost of higher delivered MU. 3F beams or finer width MLC’s (width <5 mm) have no advantage over the conventional 1 cm MLC and flat beam except that 3F beams have a shorter beam delivery time. This study demonstrate a significantly lesser spillage dose to NTID/body that of the reported literature, which is attributed to limited rotational arc length used for VMAT plans.

scholarly journals Hippocampus avoidance with fan beam and volumetric arc radiotherapy for base of skull tumours

2010 ◽  
Vol 9 (2) ◽  
pp. 87-98 ◽  
Author(s):  
Ericka Wiebe ◽  
Luca Cozzi ◽  
Slav Yartsev ◽  
Antonella Fogliata ◽  
Alessandro Clivio ◽  
...  
Keyword(s):  
Target Volume ◽  
Cognitive Effects ◽  
Intensity Modulated ◽  
Profound Influence ◽  
Base Of Skull ◽  
Delivery Technique ◽  
Arc Therapy ◽  
Specific Goal ◽  
Organ At Risk ◽  
The Impact

AbstractRadiosensitive neurogenic stem cells reside in the hippocampi, suggesting that avoidance of the hippocampi may be an important strategy to reduce potential radiation-related cognitive effects. Six patients treated for base of skull tumours were re-planned using co-planar helical fan beam arc therapy (tomotherapy) and co-planar and non-coplanar volumetric arc techniques (RapidArc). The hippocampi were contoured as avoidance structures with the specific goal of minimising the dose. Two gross target volume (GTV) to planning target volume (PTV) expansions (10 and 2 mm) were considered to evaluate the impact of margin selection on organ at risk (OAR) sparing. The dose prescription was 50 Gy to >95% of the PTV. Comparison of the hippocampus avoidance plans demonstrated the importance of non-coplanar delivery when the 10 mm margin was used. With the 2 mm margin, both co-planar and non-coplanar delivery provided similar degrees of sparing. A mean dose of 3–4 Gy and a V6Gy <5% to the hippocampi was realised with the hippocampus sparing techniques. Our comparisons suggest interventions to minimise GTV to PTV margins will have a more profound influence on multiple OAR sparing than the choice of intensity modulated arc delivery technique.

scholarly journals Volumetric Modulated Arc Radiotherapy for Early Stage Non-Small-Cell Lung Carcinoma: Is It Better Than the Conventional Static Beam Intensity Modulated Radiotherapy?

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Vincent Wing Cheung Wu ◽  
Man In Pun ◽  
Cho Pan Lam ◽  
To Wing Mok ◽  
Wah Wai Mok
Keyword(s):  
Early Stage ◽  
Small Cell Lung Carcinoma ◽  
Volumetric Modulated Arc Therapy ◽  
Intensity Modulated Radiotherapy ◽  
Small Cell ◽  
Small Cell Lung ◽  
Cell Lung Carcinoma ◽  
Intensity Modulated ◽  
Significant Difference ◽  
Arc Therapy

This study compared the performance of volumetric modulated arc therapy (VMAT) techniques: single arc volumetric modulated arc therapy (SA-VMAT) and double arc volumetric modulated arc therapy (DA-VMAT) with the static beam conventional intensity modulated radiotherapy (C-IMRT) for non-small-cell lung carcinoma (NSCLC). Twelve stage I and II NSCLC patients were recruited and their planning CT with contoured planning target volume (PTV) and organs at risk (OARs) was used for planning. Using the same dose constraints and planning objectives, the C-IMRT, SA-VMAT, and DA-VMAT plans were optimized. C-IMRT consisted of 7 static beams, while SA-VMAT and DA-VMAT plans consisted of one and two full gantry rotations, respectively. No significant difference was found among the three techniques in target homogeneity and conformity. Mean lung dose in C-IMRT plan was significantly lower than that in DA-VMAT plan P=0.04. The ability of OAR sparing was similar among the three techniques, with no significant difference in V20, V10, or V5 of normal lungs, spinal cord, and heart. Less MUs were required in SA-VMAT and DA-VMAT. Besides, SA-VMAT required the shortest beam on time among the three techniques. In treatment of early stage NSCLC, no significant dosimetric superiority was shown by the VMAT techniques over C-IMRT and DA-VMAT over SA-VMAT.

Quantifying the Impact of Introducing Modulated Arc Therapy in the Clinic

2013 ◽  
Vol 87 (2) ◽  
pp. S718
Author(s):  
L. Archambault ◽  
L. Brouard ◽  
L. Turgeon ◽  
E. Chamberland ◽  
B. Lachance
Keyword(s):  
Arc Therapy ◽  
The Impact
Sign in / Sign up

Export Citation Format

Share Document