الفهرس 
Title : Comparative dosimetric study between Volumetric Modulated Arc Therapy (VMAT), Intensity Modulated Radiotherapy (IMRT), and 3-Dimensional Conformal RadiotherapyTechniques (3D-CRT) For Definitive Chemoradiation In Patients With Locally Advanced Cancer Cervix
AbstractOnly 14 pages are availabe for public view
 |  | from | 112 |  |  |
| | | from | 112 | | |
Abstract
Introduction: Concurrent chemoradiation (CCRT) shows an overall survival benefit for locally advanced cervical cancer patients. Moreover, modern external beam radiotherapy (EBRT) techniques show better conformity, reduced toxicity, and treatment time. This trial evaluated the dosimetric parameters of 3D-CRT, IMRT and VMAT in treating locally advanced cancer patients.
Material and Methods: Fifty-four patients who had the International Federation of Gynecology and Obstetrics (FIGO) stage IIB-IVA carcinoma of the cervix were included. All patients were treated with definitive CCRT at the Radiation Therapy Department, NCI, from December 2019 to September 2020. All patients were treated with 50Gy/25fr/5 weeks with 3D-CRT plans generated by the Xio planning system. In addition, IMRT and VMAT plans were calculated on Monaco 5.11 using the Mont Carlo algorithm. The dose-volume histograms (DVH) were calculated for the target volume and organs at risk [bowel bag, bladder, femoral heads, rectum and bone marrow (BM)]. Measuring treatment delivery time (minutes), monitor units (MU), CI, and HI were calculated for each plan.
Results: In our study, the PTV V95% received ≥ 95% of the prescribed dose in all the patients. Sparing of BM with VMAT and IMRT-at different doses and volume levels was significantly better than 3D-CRT (P-value <0.0001). Dose delivered to the bowel bag was significantly low in favour of VMAT and IMRT vs 3D-CRT in V40Gy and V45Gy with (P-value < 0.001). Regarding the bladder dose, in VMAT plans dose received by 20%, and 50% of volume was more than 1·4 times less as compared to 3D-CRT with no difference in comparison to IMRT(p-value 0.0001).
There was no statistically significant difference between 3DCRT and IMRT in rectum V30Gy (p value > 0.05). Otherwise, there was a statistically significant difference in the other dosimetric parameters.
Both treatment time/sec and the number of monitor units were significantly higher in IMRT and VMAT vs 3-DCRT (p-value< 0.0001).
Conclusion: The current study demonstrated the dosimetric advantage of IMRT and VMAT in sparing BM and lowering the bowel bag dose with better conformity and dose homogenity. A further clinical study is recommended to report the impact of these results on the hematologic and gastrointestinal side effects.