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Document Type |
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Thesis |
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Document Title |
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A DOSIMETRIC COMPARISON OF VOLUMETRIC MODULATED ARC THERAPY (VMAT) AND HIGH DOSE RATE BRACHYTHERAPY (HDR) IN LOCALIZED CERVICAL CANCER RADIOTHERAPY مقارنة قياسية بين العلاج بإستخدام قوس التضمين الحجمي و أقصى معدل للجرعة للعلاج الاشعاعي عن قرب لسرطان عنق الرحم الموضعي |
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Subject |
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Faculty of Science |
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Document Language |
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Arabic |
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Abstract |
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Cervical cancer radiotherapy is usually administrated through Three-Dimensional Conformal Radiation Therapy (3D-CRT) followed by a brachytherapy (BT) boost. Several studies have evaluated the ability of external beam techniques such as Volumetric Modulated Arc Therapy (VMAT) to mimic BT plans. The aim of this study was to investigate whether VMAT can replace HDR intracavitary BT boost for patients undergoing cervical cancer radiotherapy. The CT scans for ten patients with tandem and ovoids included in this study. Target volumes, rectum, bladder, sigmoid, small bowel and both femoral heads were delineated. Two plans were carried out (a) HDR BT planned with Ir-192 source and performed by manual dwell time optimization, (b) Two partial arcs VMAT plans. The prescribed dose was 7 Gy. Dose volume parameters (DVPs) for the two plans were compared. It was found that VMAT plans achieved greater target coverage with better dose homogeneity compared to BT plans (P <0.05). VMAT plans showed a significant reduction of 16.45 %, 9.1 % and 9.32 % in rectum mean dose, maximum dose and D2cc (P= 0.012, 0.037 and 0.047) compared with BT plans. VMAT plans also showed a significant reduction of 15.48 %, 14.45 % and 13.1 % in bladder maximum dose, D2cc and sigmoid maximum dose (P= 0.028, 0.017 and 0.009) with comparable bladder mean dose and D2cc of sigmoid compared to BT plans (P= 0.445 and 0.333). In addition, VMAT plans showed no significant differences in small bowel mean and maximum doses (P= 0.508 and 0.646). On the other hand, VMAT showed significantly higher D2cc of small bowel (P= 0.016) and both femoral heads maximum point dose (P= 0.017 and 0.007) compared to BT plans. It is concluded that VMAT provides superior target coverage and offers the potential to significantly reduce the dose volume parameters of the rectum, bladder and sigmoid colon compared to brachytherapy. However, VMAT plans delivers more radiation exposures to small bowel and femoral heads compared to brachytherapy. |
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Supervisor |
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Dr. Azza Mahmoud Helal |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1440 AH
2019 AD |
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Co-Supervisor |
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Dr. Reem Mohammed Darwesh |
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Added Date |
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Tuesday, April 23, 2019 |
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Researchers
| ليلى محمود نور ولي | Noor Wali, Lila Mahmoud | Researcher | Master | |
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