Dosimetric study of coplanar template-assisted and CT-guided 125I seed implantation in the treatment of local recurrence of lung cancers / 中华放射医学与防护杂志

ABSTRACT

Objective:To evaluate the pre- and post-implantation dosimetric consistency and efficacy of CT-guided 125I radioactive seed implantation for the treatment of the local recurrence of lung cancers under the assistance of a universal coplanar template (also referred to as the universal template). Methods:This study involved 38 patients with a local recurrence of non-small cell lung cancers who received universal template-assisted 125I radioactive seed implantation in the Second Hospital of Tianjin Medical University from Jan 2009 to Dec 2015.Preoperative planning was carried out before implantation, and the prescription dose was 110 Gy.The paired T-test was adopted for cooperation between intraoperative verification result and pre-plan values of the dosimetric parameters including minimum peripheral dose (MPD), the minimum prescription doses delivered to 90% and 100% of the target volume ( D90 and D100), conformity index (CI), external index (EI), and homogeneity index (HI). The efficacy was evaluated at the 6th month after implantation according to the RECIST 1.1 (Response Evaluation Criteria in Solid Tumors). Results:All patients successively received the seed implantation.The pre-plan and post-implant dosimetric parameters were as follows MPD (222.7±26.2), (227.74±29.8) Gy; D90(130.8±13.6), (134.8±12.8) Gy; D100 (106.4±10.6), (110.7±11.8) Gy, CI ( 0.75±0.06), (0.74±0.04), EI(22.7±5.8)%, (24.3±4.8)%; HI(36.8±4.7)%, (37.2±5.3)%, the mean irradiation dose of hearts (19.3±7.2), (21.3±6.8) Gy( P> 0.05). The median follow-up period was 22.5 months (8-98 months). The median survival was 21 months (95% CI, 7.4-34.6), and the 2-year overall survival (OS), progression-free survival (PFS), and local control (LC) rate were 47.4%, 39.5%, and 83.5%, respectively. Conclusions:The universal template-assisted and CT-guided 125I radioactive seed implantation in the treatment of postoperative local recurrence of non-small cell lung cancers can achieve the goal of the preoperative TPS planning during the operation and achieve good efficacy.It is a minimally invasive, accurate, safe and effective therapy.