Dear Authors,
If you believe that your paper was mistakenly rejected by other leading journals and you do not agree with final decision, the editors of Reports of Practical Oncology and Radiotherapy offer new fast track review. You may submit your manuscript to Reports of Practical Oncology and Radiotherapy together with all prior peer-reviews obtained from the other journal and your rebuttal letter. We guarantee review based decision within 72 hours from the time we will receive your manuscript.

Fast track submission process: Please submit the manuscript with all reviews and rebuttal letter by email to Dr. Michal Masternak (michal.masternak@ucf.edu) for fast review processing. To assure immediate attention the email title must to include: RPOR-fast track- Last Name First Name (of corresponding author).

Volume 17, Number 6, 2012

Exit fluence analysis using portal dosimetry in volumetric modulated arc therapy

Prabakar Sukumar, Sriram Padmanaban, Dhanabalan Rajasekaran, Muniyappan Kannan, Vivekanandan Nagarajan

Summary:

Aim

In measuring exit fluences, there are several sources of deviations which include the changes in the entrance fluence, changes in the detector response and patient orientation or geometry. The purpose of this work is to quantify these sources of errors.

Background

The use of the volumetric modulated arc therapy treatment with the help of image guidance in radiotherapy results in high accuracy of delivering complex dose distributions while sparing critical organs. The transit dosimetry has the potential of Verifying dose delivery by the linac, Multileaf collimator positional accuracy and the calculation of dose to a patient or phantom.

Materials and methods

The quantification of errors caused by a machine delivery is done by comparing static and arc picket fence test for 30 days. A RapidArc plan, created for the pelvis site was delivered without and with Rando phantom and exit portal images were acquired. The day to day dose variation were analysed by comparing the daily exit dose images during the course of treatment. The gamma criterion used for analysis is 3% dose difference and 3 mm distance to agreement with a threshold of 10% of maximum dose.

Results

The maximum standard deviation for the static and arc picket fence test fields were 0.19 CU and 1.3 CU, respectively. The delivery of the RapidArc plans without a phantom shows the maximum standard deviation of 1.85 CU and the maximum gamma value of 0.59. The maximum gamma value for the RapidArc plan delivered with the phantom was found to be 1.2. The largest observed fluence deviation during the delivery to patient was 5.7% and the maximum standard deviation was 4.1 CU.

Conclusion

It is found from this study that the variation due to patient anatomy and interfraction organ motion is significant.

Signature: Rep Pract Oncol Radiother, 2012; 17(6) : 324-331


« back

 
INDEXED IN:

Indexed in: EMBASE®, the Excerpta Medica database, the Elsevier BIOBASE (Current Awareness in Biological Sciences) and in the Index Copernicus.

http://www.sciencedirect.com/science/journal/15071367/19/2