Research On Multi-modal Imaging-guided Methods Adapted To ¹²⁵Ⅰ Seeds Implantation To Improve Therapy Efficiency

Objective: To study utilization of multi-modal imaging techniques to assist radioactive ¹²⁵Ⅰ particle implantation in tumor targeting,target delineating,particles embedding in the process of real-time monitoring and postoperative dosimetry verification.With whole guidance of multi-modal imaging techniques,quality assurance and quality control of radioactive ¹²⁵Ⅰ particle implantation can be evaluated,thus increasing the gain ratio of radioactive particle implantation.Method: Retrospectively analyzed patients treated with ¹²⁵Ⅰ particles implantation from March 2012 to February 2015 in our hospital,including 59 patients with non-small cell lung cancer staging IIIb-IV（NSCLC group）,31 patients with metastases to lung（metastic lung cancer group）,23 patients with central lung cancer with unclear limit to surrounding normal tissues（SPEC T/CT group）;retrospectively analyzed 13 patients with localregion prostate cancer（low to intermediate risk）treated with ¹²⁵Ⅰ particles implantation from March 2014 to February 2015 in our hospital（ultrasound-guided group）.Preoperative CT examination taken from all patients,and SPEC T/CT taken from SPECT/CT group in order to make clear of the biological targets were uploaded to therapy planning system（TPS）,in which to delineate target area and organ at risk（OAR）area according to the prescribed dose,draw the dose-volume histogram（DVH）and optimize dosimetry planning for implantation.Radioactive particles implantation process of NSCLC group,metastic lung cancer group and SPECT/CT group were operated under guidance of CT technique;operations of ultrasound-guided group treating prostate cancer patients were conducted in real-time guidance of ultrasound image after completion of ultrasound and preoperative CT image fusion.Postoperative CT examination was taken and CT images were uploaded to the TPS to conduct dosimetry verification.Postoperative follow-up was conducted in evaluation of short-term curative efficacy,long-term curative efficacy and complications after ¹²⁵Ⅰ particle implantation.Result: Prescribed dose was 110 Gy in patients with lung cancer and 140 Gy in prostate cancer patients.Delineated target planning on preoperative C T image.Preoperative SPECT/CT can clearly show the limits between tumor lesions and normal tissues.A CT scan was used during the process of particles embedding to adjust and validate the position of needles and particles.Ultrasound was used for real-time monitoring and correction during the process of implantation into prostate cancer after completion of CT scan and ultrasound fusion.Postoperative dosimetry verification results showed that:（1）NSCLC group: postoperative average MPD and D90 were 113.0±13.7Gy and 140.9±15.1Gy respectively,with no statistic differe nce from preoperative dosimetry（P>0.05）,with D90>MPD in 55 patients of 59 patients（93.2%）.（2）Metastic lung cancer group: postoperative average MPD and D90 were 112.2±12.0Gy and 120.3±10.2Gy respectively,with no statistic difference from preoperative dosimetry（P>0.05）,D90>MPD was in 27 patients of 31 patients,with a coincidence rate of 87.1%;（3）SPECT/CT group: postoperative average MPD and D90 were 115.3±3.1Gy and 140.0±2.8Gy respectively,with D90 greater than MPD in 22 patients,with an average CI of 0.9（0.91-1.05）;（4）Ultrasound-guided group: postoperative average MPD and D90 were 141.2±4.1Gy and 169.4±3.2Gy respectively in 13 cases of prostate cancer patients,all o f which D90 were higher than prescribed dose and OAR does were lower than normal tissue limits,with an average CI of 1.0（0.95-1.03）.Postoperative follow-up of NSCLC group,metastic lung cancer group and SPEC T/CT group showed short-term efficacy were 84.7%,90.3% and 87.0% respectively.Response rate of ultrasound-guided group was 92.3%.O ne year overall survival（OS）of NSCLC group,metastic lung cancer group and SPEC T/C T group were 89.8%,83.9% and 91.3% respectively,with 2 years OS of 52.5%,41.9% and 56.5% respectively.One year progression-free survival（PFS）of NSCLC group,metastic lung cancer group and SPEC T/CT group were 66.1%,67.7%,69.6% respectively,with 2 years of PFS of 35.6%,29.0% and 39.1% respectively.O ne year and 2 years OS of ultrasound-guided group were 100% and 92.3% respectively,with 1 year and 2 years PFS of 92.3% and 77.0% respectively.Postoperative pneumothorax occurred in 33.6%,acute radioactive pneumonia symptoms in 19.5% and radioactive esophagitis in 14.2% of patients with lung cancer on average.N ine cases of 13 patients in ultrasound-guided group occurred in bladder irritation symptoms,3 cases with hematuria and 2 cases of perineal discomfort symptoms.No serious late radiation reaction or radioactive damage was reported in this study.Conclusion:（1）The application of a variety of imaging techniques in guidance of target delineating can optimize the treatment plan and improve tumor targeting in treatment.（2）Using a single image technology or image fusion technique o n real-time monitoring of particles implantation surgery can obtain good conformity.（3）Under the guidance of multi-modal imaging techniques,great tumor local control and few postoperative complications can be achieved,thus improving the gain ratio of radioactive particles implantation treatment.