Thermoplastic immobilizing masks have dosimetric effects on the patient’s skin dose. The thermoplastic percentage depth dose (PDD), equivalent thickness of water for the masks and surface doses were determined. The s...Thermoplastic immobilizing masks have dosimetric effects on the patient’s skin dose. The thermoplastic percentage depth dose (PDD), equivalent thickness of water for the masks and surface doses were determined. The surface dose factors due to the thermoplastic mask was found to be 1.7949, 1.9456, 2.0563, 2.1967, 2.3827, 2.5459 and 2.6565 for field sizes of 5 × 5, 8 × 8, 10 × 10, 12 × 12, 15 × 15, 18 × 18 and 20 × 20 cm<sup>2</sup> respectively which shifted the percentage depth dose curve to lower values. The physical thermoplastic thickness was measured to be between 2.30 and 1.80 mm, and the equivalent thicknesses of water, d<sub>e</sub>, were determined to be between 1.2 and 1.00 mm. This meant that, as the mask thickness decreased, its water equivalent thickness also decreased. The presence of the mask material increased the skin dose to a factor of 1%. The thermoplastic mask factor was also found to be 0.99.展开更多
目的:分析和比较在食管癌放射治疗中胸腹平架和头颈肩架固定装置对患者的体位固定效果。方法:回顾性筛选2020年11月至2021年4月在某院放疗科行放射治疗的41例病变位于胸中段或胸上段的食管癌患者,其中20例采用胸腹平架固定(作为胸腹平架...目的:分析和比较在食管癌放射治疗中胸腹平架和头颈肩架固定装置对患者的体位固定效果。方法:回顾性筛选2020年11月至2021年4月在某院放疗科行放射治疗的41例病变位于胸中段或胸上段的食管癌患者,其中20例采用胸腹平架固定(作为胸腹平架组),21例采用头颈肩架固定(作为头颈肩架组)。比较X(左右)、Y(头脚)、Z(腹背)、RX(矢状面)、RY(横断面)、RZ(冠状面)方向上的整体摆位误差、胸锁关节摆位误差和肩锁关节摆位误差及靶区外放范围。采用SPSS 25.0软件进行统计学分析。结果:在整体摆位误差方面,胸腹平架组在X、RX和RZ方向上显著小于头颈肩架组(0.15 cm vs 0.21 cm,P=0.000;0.66°vs 0.80°,P=0.034;0.52°vs 0.80°,P=0.000),但在Y方向上显著大于头颈肩架组(0.26 cm vs 0.22 cm,P=0.002)。在胸锁关节摆位误差方面,胸腹平架组在X、RY、RZ方向上显著小于头颈肩架组(0.15 cm vs 0.24 cm,P=0.000;0.92°vs 1.19°,P=0.000;0.63°vs 1.00°,P=0.000)。在肩锁关节摆位误差方面,胸腹平架组在RX方向上显著小于头颈肩架组(0.90°vs 1.08°,P=0.019),在Y和RY方向上显著大于头颈肩架组(0.26 cm vs 0.22 cm,P=0.024;0.81°vs 0.62°,P=0.016)。在整体靶区外放方面,胸腹平架组和头颈肩架组在X、Y和Z方向上需要的外放范围分别为0.43、0.66、0.46 cm和0.60、0.58、0.43 cm。结论:对于需要放射治疗的胸中上段食管癌患者,胸腹平架和头颈肩架在不同方向上的固定效果各有优劣,临床上应该根据具体情况选择合适的固定装置。展开更多
文摘Thermoplastic immobilizing masks have dosimetric effects on the patient’s skin dose. The thermoplastic percentage depth dose (PDD), equivalent thickness of water for the masks and surface doses were determined. The surface dose factors due to the thermoplastic mask was found to be 1.7949, 1.9456, 2.0563, 2.1967, 2.3827, 2.5459 and 2.6565 for field sizes of 5 × 5, 8 × 8, 10 × 10, 12 × 12, 15 × 15, 18 × 18 and 20 × 20 cm<sup>2</sup> respectively which shifted the percentage depth dose curve to lower values. The physical thermoplastic thickness was measured to be between 2.30 and 1.80 mm, and the equivalent thicknesses of water, d<sub>e</sub>, were determined to be between 1.2 and 1.00 mm. This meant that, as the mask thickness decreased, its water equivalent thickness also decreased. The presence of the mask material increased the skin dose to a factor of 1%. The thermoplastic mask factor was also found to be 0.99.
文摘目的:分析和比较在食管癌放射治疗中胸腹平架和头颈肩架固定装置对患者的体位固定效果。方法:回顾性筛选2020年11月至2021年4月在某院放疗科行放射治疗的41例病变位于胸中段或胸上段的食管癌患者,其中20例采用胸腹平架固定(作为胸腹平架组),21例采用头颈肩架固定(作为头颈肩架组)。比较X(左右)、Y(头脚)、Z(腹背)、RX(矢状面)、RY(横断面)、RZ(冠状面)方向上的整体摆位误差、胸锁关节摆位误差和肩锁关节摆位误差及靶区外放范围。采用SPSS 25.0软件进行统计学分析。结果:在整体摆位误差方面,胸腹平架组在X、RX和RZ方向上显著小于头颈肩架组(0.15 cm vs 0.21 cm,P=0.000;0.66°vs 0.80°,P=0.034;0.52°vs 0.80°,P=0.000),但在Y方向上显著大于头颈肩架组(0.26 cm vs 0.22 cm,P=0.002)。在胸锁关节摆位误差方面,胸腹平架组在X、RY、RZ方向上显著小于头颈肩架组(0.15 cm vs 0.24 cm,P=0.000;0.92°vs 1.19°,P=0.000;0.63°vs 1.00°,P=0.000)。在肩锁关节摆位误差方面,胸腹平架组在RX方向上显著小于头颈肩架组(0.90°vs 1.08°,P=0.019),在Y和RY方向上显著大于头颈肩架组(0.26 cm vs 0.22 cm,P=0.024;0.81°vs 0.62°,P=0.016)。在整体靶区外放方面,胸腹平架组和头颈肩架组在X、Y和Z方向上需要的外放范围分别为0.43、0.66、0.46 cm和0.60、0.58、0.43 cm。结论:对于需要放射治疗的胸中上段食管癌患者,胸腹平架和头颈肩架在不同方向上的固定效果各有优劣,临床上应该根据具体情况选择合适的固定装置。
