scholarly journals A retrospective planning analysis comparing intensity modulated radiation therapy ( IMRT ) to volumetric modulated arc therapy ( VMAT ) using two optimization algorithms for the treatment of early‐stage prostate cancer

2013 ◽  
Vol 60 (3) ◽  
pp. 84-92 ◽  
Author(s):  
Craig A. Elith ◽  
Shane E. Dempsey ◽  
Helen M. Warren‐Forward
Author(s):  
Craig A. Elith ◽  
Shane E. Dempsey ◽  
Helen M. Warren-Forward

AbstractAimThis study compared the acute toxicities reported during radiotherapy treatment using either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) to deliver a moderate hypo-fractionated treatment for early-stage prostate cancer.Material and methodsAcute toxicities are routinely reported at the clinical site for all patients using the Common Terminology Criteria for Adverse Events. Toxicity assessment is performed on day 1 of treatment, then once weekly thereafter. The recorded toxicities of 40 cases treated with five-field IMRT, and 32 cases treated using VMAT were retrospectively compared. All cases were prescribed 73·68 Gy in 28 fractions. Eight symptoms were assessed; diarrhoea, proctitis, fatigue, pain, dermatitis, urinary frequency, urinary retention and urinary tract pain.ResultsIn terms of the overall toxicity recorded, VMAT was shown to reduce the toxicities of dermatitis, fatigue, pain and urinary frequency (p<0·05). Using IMRT, grade 2 toxicities were reported for proctitis, pain, urinary frequency, urinary retention and urinary tract pain. Using VMAT, grade 2 toxicities were reported for urinary frequency and urinary retention.FindingsThe research reported here is one of the first publications to demonstrate that VMAT is associated with decreased toxicities compared with IMRT for the treatment of early-stage prostate cancer.


2019 ◽  
Vol 18 ◽  
pp. 153303381984448
Author(s):  
Xiangyu Ma ◽  
Huagang Yan ◽  
Ravinder Nath ◽  
Zhe Chen ◽  
Haiyun Li ◽  
...  

Objective: To evaluate the benefits of adaptive imaging with automatic correction compared to periodic surveillance strategies with either manual or automatic correction. Methods: Using Calypso trajectories from 54 patients with prostate cancer at 2 institutions, we simulated 5-field intensity-modulated radiation therapy and dual-arc volumetric-modulated arc therapy with periodic imaging at various frequencies and with continuous adaptive imaging, respectively. With manual/automatic correction, we assumed there was a 30/1 second delay after imaging to determine and apply couch shift. For adaptive imaging, real-time “dose-free” cine-MV images during beam delivery are used in conjunction with online-updated motion pattern information to estimate 3D displacement. Simultaneous MV-kV imaging is only used to confirm the estimated overthreshold motion and calculate couch shift, hence very low additional patient dose from kV imaging. Results: Without intrafraction intervention, the prostates could on average have moved out of a 3-mm margin for ∼20% of the beam-on time after setup imaging in current clinical situation. If the time interval from the setup imaging to beam-on can be reduced to only 30 seconds, the mean over-3 mm percentage can be reduced to ∼7%. For intensity-modulated radiation therapy simulation, with manual correction, 110 and 70 seconds imaging periods both reduced the mean over-3 mm time to ∼4%. Automatic correction could give another 1% to 2% improvement. However, with either manual or automatic correction, the maximum patient-specific over-3 mm time was still relatively high (from 6.4% to 12.6%) and those patients are actually clinically most important. In contrast, adaptive imaging with automatic intervention significantly reduced the mean percentage to 0.6% and the maximum to 2.7% and averagely only ∼1 kV image and ∼1 couch shift were needed per fraction. The results of volumetric-modulated arc therapy simulation show a similar trend to that of intensity-modulated radiation therapy. Conclusions: Adaptive continuous monitoring with automatic motion compensation is more beneficial than periodic imaging surveillance at similar or even less imaging dose.


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