Field-in-Field Technique Improves the Dosimetric Outcome of Treatment Plans Compared with the Three-Dimensional Conformal Radiation Therapy for Esophageal Cancer Radiotherapy

Abstract

The aim of this study was to evaluate and compare the dosimetric parameters of three-dimensional conformal radiotherapy (3D-CRT) and field-in-field (FIF) techniques for patients with esophageal cancer. Twenty (20) patients with esophageal cancer participated in this study. Two planning techniques (FIF and 3D-CRT) were generated for each patient by the TiGRT treatment planning system. Two indices namely: Dose Homogeneity Index (DHI) and Conformity index (CI), as well as maximum dose, mean dose, minimum dose, dose received by 2% of the target volume (D 2 ); dose received by 98% of the target volume (D 98 ); volume received greater than 107% of the prescribed dose (V> 107%); volume received less than 95% of the prescribed dose (V< 95%); Dose received by organ at risks (OARs) and total Monitor Unit (MUs) were used for the comparison. The mean values were then compared using paired sample t-test. The FIF technique reduced the maximum dose and mean dose in the planning target volume (PTV). The FIF technique had higher D98, lower D 2 and V< 95%. The FIF plan recorded a better DHI than the 3D-CRT technique. However, the FIF did not show any significant differences in minimum dose, V>107%, CI and MUs compared with the 3D-CRT technique. In addition, the FIF technique demonstrated reduced dose received by the OARs in the treated region. The FIF technique enables better dose distribution in the PTV and reduces dose to OARs in esophageal radiotherapy.

Field-in-Field Technique With Intrafractionally Modulated Junction Shifts for Craniospinal Irradiation Planning With Three-Dimensional Conformal Radiation Therapy

“…This technique is also called forward-planned IMRT. This variation of 3D-CRT technique of CSI increases dose homogeneity in the target volume while decreasing the absorbed dose in the irradiated tissues outside the targeted tissue [9]. Furthermore, pediatric patients do not usually require the addition of many reduction fields because of the relatively uniform depth of the spinal column; but in adults, several fields may be required, which can be weighted as much as 10%-12% per field in the lower spine.…”