| Objective: To study the pathological changes,imaging evaluation methods of the treatment for prostate cancer.Study the characteristics of the double needle laser ablation.To discuss the value of finite element simulation in develop of conformal ablation strategies for prostate cancer.Discuss the clinical value and safety of laser ablation in treatment of localized prostate cancerMethods: The beagle dogs were underwent single needle focal laser ablation of prostate guided by transrectal ultrasonography.The dogs were sacrificed,then the gross pathological and histopathological examination were done.The value of different imaging examinations in evaluating the ablation effect could be done through observation of pathological change in ablation lesions and comparison of the gross pathologic prostate ablation lesions measurements by contrast-enhanced ultrasonography(CEUS)and dynamic contrast enhanced MRI(DCE-MRI)measurement results.The finite element analysis method is used to simulate the effect of the single needle laser and double needle laser on the prostate tissue,resulting heat,and in vivo transfer process.Single needle laser ablation and double needle laser ablation were performed on the bilateral lobes of the prostate in vivo.After the operation,CEUS and pathological examination were performed to observe and measure the morphology of ablation lesions.3 localized prostate cancer patients were selected for this study.Postoperative complications were recorded with follow-up for 1year.After ablation,the short and mid-term effects were evaluated by PSA value examination and imaging examination.Results:Pathological examination revealed a clear 4-layers-change in the ablation lesion: the cavity area,the carbonization zone,the coagulation necrosis zone and the edema zone.There were no statically significant differences(P>0.05)between average lesion volume on DCE-MRI,CEUS and average lesion volume at histology.Finite element simulation showed that focal ablation volume increased by 9.3%,15.7%and 17.9% respectively,with the double needle spacing was 6mm,9mm,12 mm.When the double needle spacing was greater than 9mm,there would be no ablation zone between the two needles.Double needle combination of laser ablation focal ablation volume measured by CEUS is greater than 2 times of single needle ablation focal volume(P < 0.05).The coefficient of variation for each diameter of double needle ablation lesions were 13.34%,7.07%,8.26%.The boundary of the double needle ablation lesions was not as good as that of the single needle ablation.All patients were successfully completed the focal ablation,Two mainly postoperative complications have been observed,such as hematuria and local pain.Serum PSA value decreased significantly while CEUS showed no perfusion in ablation lesions after treatment.No metastatic lesions were found in the imaging examination in 1year after treatment.Conclusion: Transrectal ultrasonography-guided laser ablation of canine prostate is a clear,safe and reliable method to cause tissue necrosis,which is confirmed by pathology analysis.CEUS and DCE-MRI can all be used as a reliable method for evaluation of laser ablation.Accurate finite element simulation equation can accurately simulate the experimental results of laser ablation of canine prostate,which can be used to develop conformal ablation strategies for prostate cancer.Compared with the single needle mode,the double needle laser combined ablation can increase the range of ablation lesion and improve the efficiency of ablation.Focal laser ablation is safe and feasible for the treatment of localized prostate cancer.Ablation therapy has achieved satisfied short and medium-term effects. |
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