Patient-specific quality assurance on a Varian Halcyon linear accelerator using a PTW Octavius 4D device

Author(s):  
T. Aland ◽  
T. Jarema ◽  
J. V. Trapp ◽  
T. Kairn
2018 ◽  
Vol 18 (02) ◽  
pp. 138-149
Author(s):  
P. Niyas ◽  
K. K. Abdullah ◽  
M. P. Noufal ◽  
R. Vysakh

AbstractAimThe Electronic Portal Imaging Device (EPID), primarily used for patient setup during radiotherapy sessions is also used for dosimetric measurements. In the present study, the feasibility of EPID in both machine and patient-specific quality assurance (QA) are investigated. We have developed a comprehensive software tool for effective utilisation of EPID in our institutional QA protocol.Materials and methodsPortal Vision aS1000, amorphous silicon portal detector attached to Clinac iX—Linear Accelerator (LINAC) was used to measure daily profile and output constancy, various Multi-Leaf Collimator (MLC) checks and patient plan verification. Different QA plans were generated with the help of Eclipse Treatment Planning System (TPS) and MLC shaper software. The indigenously developed MATLAB programs were used for image analysis. Flatness, symmetry, output constancy, Field Width at Half Maximum (FWHM) and fluence comparison were studied from images obtained from TPS and EPID dosimetry.ResultsThe 3 years institutional data of profile constancy and patient-specific QA measured using EPID were found within the acceptable limits. The daily output of photon beam correlated with the output obtained through solid phantom measurements. The Pearson correlation coefficients are 0.941 (p = 0.0001), 0.888 (p = 0.0188) and 0.917 (p = 0.0007) for the years of 2014, 2015 and 2016, respectively. The accuracy of MLC for shaping complex treatment fields was studied in terms of FWHM at different portions of various fields, showed good agreement between TPS-generated and EPID-measured MLC positions. The comparison of selected patient plans in EPID with an independent 2D array detector system showed statistically significant correlation between these two systems. Percentage difference between TPS computed and EPID measured fluence maps calculated for number of patients using MATLAB code also exhibited the validity of those plans for treatment.


2018 ◽  
Vol 56 ◽  
pp. 67-68 ◽  
Author(s):  
M. Zani ◽  
S. Calusi ◽  
R. Doro ◽  
N. Bellosi ◽  
M. Cassinelli ◽  
...  

2016 ◽  
Author(s):  
◽  
Jason Stanford

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Advance treatment techniques, such as IMRT and dynamic conformal arc delivery, are novel radiation treatment procedures at the forefront of accurate and precise radiotherapy. However, the risk of suboptimal treatment resulting in injury is far greater with these techniques due to their complexity. An in vivo quality assurance system is the most appropriate validation of the delivered dose to the patient from these techniques. The intent of this research is to propose an in vivo dosimetry quality assurance procedure using radiochromic film. This research proved that radiochromic in vivo dosimetry is a viable method of detecting spatial patient specific errors in radiotherapy; however, the process is time consuming and not sensitive enough for dosimetric errors associated with weight change. Although time consuming, in vivo radiochromic dosimetry is an attractive alternative for small cancer centers and developing countries without the large startup capital to acquire the electronic portal imaging device necessary for EPID in vivo dosimetry.


2021 ◽  
Vol 161 ◽  
pp. S1352-S1353
Author(s):  
H.L. Riis ◽  
A. Fietje ◽  
K.H. Engstrøm ◽  
U. Bernchou ◽  
C. Brink ◽  
...  

2018 ◽  
Vol 52 ◽  
pp. 137-138
Author(s):  
Luca Leandro Vigna ◽  
Ashenafi Kumela Rikitu ◽  
Eleonora Monès ◽  
Federica Puricelli ◽  
Chiara Secco ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document