Bienvenido Rafael, Quiñones Luis Ángel, Pérez Joaquín, Castro Ignacio, Gutiérrez Lucía, López Juan de Dios, Botana Javier, Iborra Maria Amparo
Mechanical Engineering and Industrial Design Department, Escuela Superior de Ingeniería, Universidad de Cádiz, Puerto Real, Cádiz, Spain.
Radiophysics Unit, Hospital Universitario Puerta del Mar, Cádiz, Spain.
Brachytherapy. 2023 Mar-Apr;22(2):250-259. doi: 10.1016/j.brachy.2022.10.011. Epub 2022 Nov 28.
This paper describes a method to evaluate the influence of 3D printed plesiotherapy applicators densities in the most clinically relevant dosimetric planes of these brachytherapy treatments. Studied densities range goes from that of water to that of air including the intermediate applicators densities made of acrylonitrile butadiene styrene and polylactic acid, materials used as Fused Deposition Modelling (FDM) filaments.
All applicators were manufactured by means of FDM 3D printing and a special empty applicator of ABS walls was designed to be filled with water or air. In each of these applicators, the values of the dose and gamma index at the surface and at the prescription depth were measured in clinical conditions, using EBT films.
Analysis of results allow us to conclude that the influence of the applicators density on the dose value in the studied materials depends on the distance at which the dose is measured. Thus, at the prescription depth no influence is observed, however this influence becomes noticeable near the surface of the applicators with dose differences of more than 10% for densities close to 0.4 g/cm.
Therefore, the density of FDM manufactured applicators should be taken into account when calculating surface dose for low density applicators, as variations caused by density can have clinical implications because is the surface dose that is associated with the toxicity of brachytherapy skin treatments.
本文描述了一种方法，用于评估3D打印近距离放射治疗敷贴器密度对这些近距离放射治疗在最具临床相关性的剂量测定平面中的影响。研究的密度范围从水的密度到空气的密度，包括由丙烯腈丁二烯苯乙烯和聚乳酸制成的中间敷贴器密度，这些材料用作熔融沉积建模（FDM）细丝。
所有敷贴器均通过FDM 3D打印制造，并设计了一种特殊的ABS壁空敷贴器，可填充水或空气。在每个敷贴器中，使用EBT薄膜在临床条件下测量表面和处方深度处的剂量值和伽马指数。
结果分析使我们得出结论，敷贴器密度对所研究材料中剂量值的影响取决于测量剂量的距离。因此，在处方深度处未观察到影响，然而，对于密度接近0.4 g/cm的敷贴器，这种影响在其表面附近变得明显，剂量差异超过10%。
因此，在计算低密度敷贴器的表面剂量时，应考虑FDM制造的敷贴器的密度，因为密度引起的变化可能具有临床意义，因为表面剂量与近距离放射治疗皮肤治疗的毒性相关。
