Physics Department, Faculty of Science, Al-Azhar University, Cairo, Egypt.
Radiology Techniques Department, College of Health and Medical Techniques, Al-Mustaqbal University, Iraq.
Asian Pac J Cancer Prev. 2024 Jun 1;25(6):2105-2112. doi: 10.31557/APJCP.2024.25.6.2105.
The aim of this study was to investigate the detector size effect on small-field dosimetry and compare the performance of 6MV WFF/FFF techniques.
We investigated the detector size effect on small-field dosimetry and compared the performance of 6MV WFF/FFF techniques. PDD, profile curves, and absorbed dose were measured in water under reference conditions with 6MV (WFF/FFF) techniques. We employed Farmer FC65-P, CC13, CC01, and IBA Razor diode, with Versa Lineac. Subsequently, we replicated this assessment for small-fields under 5cmx5cm dimensions.
For both 6MV WFF/FFF, significant dose differences (Dmax=1.47cm), were ±4.55%, ±6.7, ±12.75% and ±33.3% for 4cmx4cm, 3cmx3cm, 2cmx2cm, and 1cmx1cm, respectively. The average difference relative to D10 was observed to be ±4.66%, ±5.73%, ±6.58%, and ±8.75% for the previous field sizes. Differences between WFF/FFF are neglected values at all field sizes>2.3%, also, the output of the largest detector FC65-P is lower at 55% in the smallest field size. Variation in the profile doesn't exceed a difference of >5% in flatness between WFF/FFF at depth10cm, across all fields, while symmetry is >1%, but radiation output is considerably lower at 55% for FC65-P chamber in 2cmx2cm, 1cmx1cm compared to the CC01 chamber and Razor diode. Significant differences in 1cmx1cm, where FC65-P chamber exhibits around 49% difference compared to Razor diode with 6MV (WFF/FFF). Conclusions: Significant differences were observed in doses with various detectors. Detector-size influences the dose. WFF/FFF techniques show no major differences in small-fields dosimetry. Utilize some situations the advantage of FFF boasting a higher dose rate, consequently reducing treatment time to half.
本研究旨在探讨探测器尺寸对小野剂量学的影响，并比较 6MV WFF/FFF 技术的性能。
我们研究了探测器尺寸对小野剂量学的影响，并比较了 6MV WFF/FFF 技术的性能。在参考条件下，使用 6MV（WFF/FFF）技术在水中测量 PDD、轮廓曲线和吸收剂量。我们使用 Versa Lineac 分别采用 Farmer FC65-P、CC13、CC01 和 IBA Razor 二极管进行了测量。随后，我们在 5cmx5cm 尺寸下对小野进行了类似的评估。
对于 6MV WFF/FFF，在 4cmx4cm、3cmx3cm、2cmx2cm 和 1cmx1cm 等小野尺寸下，Dmax 分别存在 1.47cm、±4.55%、±6.7%、±12.75%和 ±33.3%的显著剂量差异。相对于 D10，观察到平均差异分别为±4.66%、±5.73%、±6.58%和±8.75%。在所有大于 2.3%的场尺寸下，WFF/FFF 之间的差异可以忽略不计，而且在最小场尺寸下，最大探测器 FC65-P 的输出降低了 55%。在所有场中，在深度 10cm 处，WFF/FFF 的轮廓变化差异不超过 5%的平坦度差异，对称性大于 1%，但在 2cmx2cm 和 1cmx1cm 中，FC65-P 腔室的辐射输出比 CC01 腔室和 Razor 二极管低得多，分别为 55%。在 1cmx1cm 中，FC65-P 腔室与 6MV（WFF/FFF）的 Razor 二极管相比，差异约为 49%，这表明存在显著差异。
各种探测器的剂量存在显著差异。探测器尺寸会影响剂量。WFF/FFF 技术在小野剂量学中没有明显差异。在某些情况下，利用 FFF 具有更高剂量率的优势，从而将治疗时间缩短至一半。
