Journal of Cancer Research and Therapeutics

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 15  |  Issue : 1  |  Page : 211--215

Search of an ideal location of isocenter in intensity-modulated radiotherapy treatment plans: A dosimetrical approach


Abhijit Mandal, Anupam Kumar Asthana, Satyajit Pradhan, Uday Pratap Shahi, Sunil Choudhary 
 Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India

Correspondence Address:
Dr. Abhijit Mandal
Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh
India

Aim: The aim of this study is to identify an ideal location of isocenter in intensity-modulated radiotherapy (IMRT) treatment plans. Materials and Methods: A total of 28 clinical target volumes and 4 English capital letters (C, L, T, and H) target volumes were considered in this study. Two IMRT treatment plans were generated for each target volume in the ECLIPSETM treatment planning system (TPS), first one with isocenter automatically placed (ISOAUTO) by TPS and the second one with geometric center-based isocenter (ISOGEOM). The geometric center of a cuboid volume, which was formed encompassing around the target volume in sagittal, transverse, and frontal planes, is considered as the geometric center of the target volume as well as the isocenter (ISOGEOM) of the IMRT plans. While performing the IMRT treatment plans using the beam angle optimization and dose volume optimization, the normal tissue objectives and target volume objectives were kept similar in both the plans. The dosimetrical parameters between the two groups of plans were compared. Results: The distance between ISOGEOM and ISOAUTO ranged from 0.16 cm to 3.04 cm with a mean and median of 0.85 cm and 0.69 cm, respectively. The ISOGEOM-based IMRT plans exhibited statistically significant advantages in total monitor units reduction (100% of cases, P ≤ 0.001), total number of field reduction (66% of cases, P ≤ 0.001), and reduction of patient mean dose (69% of cases, P ≤ 0.001) over ISOAUTO-based IMRT plans. The conformity index, homogeneity index and target mean dose were comparable between both group of plans. Conclusion: Significant dosimetrical advantages may be observed, when the geometric centroid of target volume is considered as isocenter of IMRT treatment plan.


How to cite this article:
Mandal A, Asthana AK, Pradhan S, Shahi UP, Choudhary S. Search of an ideal location of isocenter in intensity-modulated radiotherapy treatment plans: A dosimetrical approach.J Can Res Ther 2019;15:211-215


How to cite this URL:
Mandal A, Asthana AK, Pradhan S, Shahi UP, Choudhary S. Search of an ideal location of isocenter in intensity-modulated radiotherapy treatment plans: A dosimetrical approach. J Can Res Ther [serial online] 2019 [cited 2019 Sep 21 ];15:211-215
Available from: http://www.cancerjournal.net/article.asp?issn=0973-1482;year=2019;volume=15;issue=1;spage=211;epage=215;aulast=Mandal;type=0