| Measured and calculated peripheral dose in IMRT and vmat techniques in prostate cancer in radiotherapy |
| Paper ID : 1033-ISCH |
| Authors |
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Asmaa Mohammed Taha * Medical physicist, Radiotherapy Department, Nasser Institute Hospital, Cairo, Egypt |
| Abstract |
| Introduction . Intensity-Modulated Radiotherapy (IMRT) and Volumetric-Modulated Arc Therapy (VMAT) are advanced forms of radiotherapy techniques used in prostate cancer. some patients treated with ionizing radiations,can later develop induced secondary malignancy in organs far from the original tumor . It is therefore important to establish the doses that are absorbed in those distant organs. known as “peripheral doses” Methods 20 patients are scanned on c.t where the prostate and OARs are delineated and R50% , also dose spillage also are estimated in IMRT and Vmat techniques ,then the peripheral dose for these prostate cases are measured on linac using ionization chamber of type iba FC65-G . These peripheral doses are measured at distance 5cm, 10 cm and 15 cm from the isocenter of prostate with IMRT and Vmat technique Results there is significant difference (p <0.05) in IMRT and Vmat techniques with respect to peripheral dose that measured at distances 5cm 10cm, 15cm from prostate isocenter on linac where the peripheral dose at 5cm decrease from 9.4cGy with IMRT to 12.4cGy with VMAT techniques,, when the distance increase to 10 cm and 15 cm, the peripheral dose decrease from3.9cGy to 1.6 cGy from 0.25 cGy to 0.07cGy from IMRT to VMAT at distances 5cm and 10 cm, respectively. From R50% and dose spillage point of view, the R50% decrease from 1.64 to 1.59 from IMRT to VMAT. there is not significant difference ( p > 0.05)in dose spillage between IMRT to VMAT were 0.019 and 0.015, respectively. |
| Keywords |
| Prostate cancer,Radiotherapy, IMRT VMAT, peripheral dose |
| Status: Abstract Accepted (Poster Presentation) |