Dosimetric Comparison of Intensity-Modulated Radiotherapy versus Three-Dimensional Conformal Radiotherapy for Patients with Brain Tumors

• 作者: Doaa M. Al Zayat Ehab M. Attalla Hassan S. Abouelenein Wafaa Khalil Yasser M. Elkem
• 来源期刊: 放射学期刊(英文)
• 学科: 医学
• 关键词: BRAIN CANCER 3DCRT IMRT
• 年，卷（期）: 2014,（1）
• 页码范围: 85-96
• 页数: 12页
• 分类号: R73

摘要

Purpose: To compare target dose distribution and dose to normal tissue for brain tumors using intensity-modulated and three-dimensional conformal radiotherapy. Methods and Materials: Twelve patients selected in the present study compared the dosimetry of intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3DCRT) techniques in patients treated with different diagnosis brain tumor. All patients underwent computed tomography planning in conjunction with magnetic resonance imaging fusion. Prescription dose and normal-tissue constraints were identical for both plans. The tolerance level for maximum dose was 6.0 Gy for lenses and 54.0 Gy for brain stem, and optical nerves. Target coverage was evaluated with the D98%, D95% and D2%. Normal tissue dose was evaluated with the maximum dose to lenses, brain stem, and optical nerves. Results: Mean and standard deviation values of PTV 98%, PTV 95% and PTV 2% in IMRT these values were 94.6 ± 2.3, 96.56 ± 1.67 and 106.5 ± 1.87 respectively;for 3DCRT were 92.7 ± 3.09, 95.58 ± 1.24 and 104.45 ± 2.73 respectively. IMRT plan provided reduced dose to brainstem (72.17 ± 29.967) and lenses (2.43 ± 2.39) relative to the 3DCRT plans for brainstem (73.05 ± 34.59) and lenses (7.65 ± 23.24). But optic nerves with IMRT significantly received higher doses (38.86 ± 32.15) than 3D-CRT (27.57 ± 31.45). Conclusion: Dose coverage of the planning target volume (PTV) and organ at risk (OAR) was better with IMRT. If PTV is distant to optical nerves and brainstem 3DCRT technique can be applied, and if the PTV is nearby OAR intensity-modulated treatment technique should be used.