Kholin V V, Libson I L
Med Radiol (Mosk). 1984 Nov;29(11):86-9.
The paper is concerned with the problem of uneven irradiation of tumors using standard grid diaphragms on Soviet gamma-apparatuses. It has been shown that the utmost spatial heterogeneity is formed by using the C-4 grid with the source-surface distance (SSD) of 47 cm. The degree of spatial heterogeneity formed by the C-3, C-2, C-1 and C-5 grids is less pronounced. An increase in SSD results in the formation of more even irradiation. In uneven irradiation of tumors the nature of dose fractionation changes and it should be taken into account in the planning of radiotherapy.
本文关注的是苏联伽马设备使用标准格栅准直器时肿瘤照射不均匀的问题。结果表明，使用源皮距（SSD）为47厘米的C - 4格栅会形成最大程度的空间不均匀性。C - 3、C - 2、C - 1和C - 5格栅形成的空间不均匀程度则不太明显。源皮距增加会导致形成更均匀的照射。在肿瘤的不均匀照射中，剂量分割的性质会发生变化，在放射治疗计划中应予以考虑。
