Objective To explore the efficacy of extracting biopsy needle pose in chest CT images based on point cloud processing.Methods Three-dimensional point clouds were generated through segmentation of chest CT images and surface reconstruction.Spatial point cloud clustering and geometric constraints were applied to filter regions contained the puncture needle in space.The principal direction of the needle was judged using principal component analysis,and a cylindrical model was constructed to enclose the needle data.Then random sample consensus algorithm was used for needle trajectory fitting to accurately extract the spatial position and orientation of the puncture needle.The efficacy of the above method was evaluated using a 3D-printed anatomical model based on common clinical combinations of puncture depths and angles.Results The anatomical model experiments showed a 100％success rate in puncture needle identification,with angular error of(1.013±0.424)° and positional error of(2.023±1.553)mm,indicating that this method had good accuracy and stability.Conclusion The puncture needle's position in chest CT images could be extracted with high precision based on point cloud processing.

Objective To compare the efficacy and safety of CT-guided percutaneous radiofrequency ablation(RFA)and cryoablation(CRYO)combined with synchronous biopsy of pulmonary nodules.Methods Totally 62 patients with pulmonary nodules who underwent CT-guided percutaneous ablation with either RFA(n=30)or argon-helium CRYO(n=32)combined with simultaneous biopsy were enrolled,and the regarding postoperative complication rates and 1-year local control outcomes were compared.Results All patients successfully completed both ablation and biopsy procedures.In RFA group,the mean diameter of lesion was(1.43±0.33)cm,and the biopsy positive rate was 90.00%(27/30).Post-biopsy intrapulmonary hemorrhage extent immediately increased by 0.60(0.28,1.63)cm.Hemoptysis,pneumothorax requiring chest tube placement and infectious cavities observed in 2(2/30,6.67%),6(6/30,20.00%)and 4 cases(4/30,13.33%),respectively,and the 1-year local control rate in RFA group was 90.00%(27/30).In CRYO group,the mean diameter of lesion was(1.59±0.34)cm,and the biopsy positive rate was 100%(32/32).Post-biopsy intrapulmonary hemorrhage extent increased by 1.20(0.60,1.83)cm.Hemoptysis occurred in 7 cases(7/32,21.88%),and pneumothorax requiring chest tube placement was noticed in 8 cases(8/32,25.00%),while no infectious cavity was observed.The 1-year local control rate in CRYO group reached 96.88%(31/32).Statistical difference of infectious cavity was found between groups(P＜0.05).Conclusion Simultaneous biopsy during CT-guided percutaneous RFA and CRYO for lung nodules were both efficient and safe,while the former with relative higher incidence of infectious cavity.

CT-guided thermal ablation is a critical modality for treating lung cancer.Invasive thermometry techniques demonstrated sufficient accuracy for monitoring temperature of the target area during ablation,but their clinical application were limited since procedural invasiveness and relatively high risk of complications.Being non-invasive,safe and capable of global monitoring,non-invasive thermometry techniques have broad application prospects.The status of non-invasive thermometry techniques for CT-guided thermal ablation for lung cancer were reviewed in this article.

Objective To compare the efficacy and safety of CT-guided percutaneous radiofrequency ablation(RFA)and cryoablation(CRYO)combined with synchronous biopsy of pulmonary nodules.Methods Totally 62 patients with pulmonary nodules who underwent CT-guided percutaneous ablation with either RFA(n=30)or argon-helium CRYO(n=32)combined with simultaneous biopsy were enrolled,and the regarding postoperative complication rates and 1-year local control outcomes were compared.Results All patients successfully completed both ablation and biopsy procedures.In RFA group,the mean diameter of lesion was(1.43±0.33)cm,and the biopsy positive rate was 90.00%(27/30).Post-biopsy intrapulmonary hemorrhage extent immediately increased by 0.60(0.28,1.63)cm.Hemoptysis,pneumothorax requiring chest tube placement and infectious cavities observed in 2(2/30,6.67%),6(6/30,20.00%)and 4 cases(4/30,13.33%),respectively,and the 1-year local control rate in RFA group was 90.00%(27/30).In CRYO group,the mean diameter of lesion was(1.59±0.34)cm,and the biopsy positive rate was 100%(32/32).Post-biopsy intrapulmonary hemorrhage extent increased by 1.20(0.60,1.83)cm.Hemoptysis occurred in 7 cases(7/32,21.88%),and pneumothorax requiring chest tube placement was noticed in 8 cases(8/32,25.00%),while no infectious cavity was observed.The 1-year local control rate in CRYO group reached 96.88%(31/32).Statistical difference of infectious cavity was found between groups(P＜0.05).Conclusion Simultaneous biopsy during CT-guided percutaneous RFA and CRYO for lung nodules were both efficient and safe,while the former with relative higher incidence of infectious cavity.

Multimodal tumor therapy system is an integrated treatment system that combined deep cryoablation and radiofrequency ablation(RFA),with key benefit of remodeling tissue properties through cryoablation process,reduce local impedance,blood perfusion and thermal insulation effects of gases,thereby considerably boosting the efficiency and reach of subsequent RFA.Interventional Physician Branch of Shanghai Medical Doctor Association,the Solid Tumor Theranostics Committee of the Shanghai Anti-Cancer Association,Chinese Anti-Cancer Association Committee of Tumor Minimally Invasive Therapy and the Innovative and Translational Consortium for Tumor Multi-Modal Minimally Invasive Diagnosis and Treatment of Chinese Society of Biomedical Engineering organized relevanted experts in the field of tumor treatment in China to discuss and formulated this expert consensus,in order to standardize the procedures of multimodal ablation therapy for pulmonary tumors and enhance therapeutic effectiveness.

Objective To observe the impact factors of vascular heat sink effect during in vitro microwave ablation(MWA)of porcine lung.Methods Simulation models were established using in vitro porcine lung tissue blocks based on isobaric inflation with an air pump and cyclic perfusion of duck blood with a glass tube and peristaltic pump,etc.MWA was performed under 8 different combining conditions(vessel diameter of 3 or 5 mm,blood perfusion of 30 or 50 cm/s,as well as distance between vessel and ablation antenna of 5 or 10 mm)each for 3 times.The highest temperature TV on vessel side and TC on control side during MWA,and ablation depth DV on vessel side and DC on control side after MWA were recorded.Multi-factor linear regression equations were constructed based on simulated vessel diameters,blood perfusion and distance between vessel and ablation antenna,and the impact factors of|TC-TV|and|DC-DV|were screened,respectively.Results Simulated vessel diameter showed linear positive correlation with both|TC-TV|and|DC-DV|(both P＜0.001).Simulated distance between vessel and ablation antenna showed linear negative correlation with both|TC-TV|and|DC-DV|(both P＜0.001),and the latter had more obvious impact on vascular heat sink effect than the former.Meanwhile,no significant linear relationship was found between simulated blood perfusion and|TC-TV|nor|DC-DV|(both P＞0.05).Conclusion Simulated vessel diameter and distance between vessel and ablation antenna were both impact factors of vascular heat sink effect during in vitro MWA of porcine lung,and the latter was more influential,whereas simulated blood perfusion showed no significant impact on it.

CT-guided thermal ablation is a critical modality for treating lung cancer.Invasive thermometry techniques demonstrated sufficient accuracy for monitoring temperature of the target area during ablation,but their clinical application were limited since procedural invasiveness and relatively high risk of complications.Being non-invasive,safe and capable of global monitoring,non-invasive thermometry techniques have broad application prospects.The status of non-invasive thermometry techniques for CT-guided thermal ablation for lung cancer were reviewed in this article.

Objective To observe the impact factors of vascular heat sink effect during in vitro microwave ablation(MWA)of porcine lung.Methods Simulation models were established using in vitro porcine lung tissue blocks based on isobaric inflation with an air pump and cyclic perfusion of duck blood with a glass tube and peristaltic pump,etc.MWA was performed under 8 different combining conditions(vessel diameter of 3 or 5 mm,blood perfusion of 30 or 50 cm/s,as well as distance between vessel and ablation antenna of 5 or 10 mm)each for 3 times.The highest temperature TV on vessel side and TC on control side during MWA,and ablation depth DV on vessel side and DC on control side after MWA were recorded.Multi-factor linear regression equations were constructed based on simulated vessel diameters,blood perfusion and distance between vessel and ablation antenna,and the impact factors of|TC-TV|and|DC-DV|were screened,respectively.Results Simulated vessel diameter showed linear positive correlation with both|TC-TV|and|DC-DV|(both P＜0.001).Simulated distance between vessel and ablation antenna showed linear negative correlation with both|TC-TV|and|DC-DV|(both P＜0.001),and the latter had more obvious impact on vascular heat sink effect than the former.Meanwhile,no significant linear relationship was found between simulated blood perfusion and|TC-TV|nor|DC-DV|(both P＞0.05).Conclusion Simulated vessel diameter and distance between vessel and ablation antenna were both impact factors of vascular heat sink effect during in vitro MWA of porcine lung,and the latter was more influential,whereas simulated blood perfusion showed no significant impact on it.

Multimodal tumor therapy system is an integrated treatment system that combined deep cryoablation and radiofrequency ablation(RFA),with key benefit of remodeling tissue properties through cryoablation process,reduce local impedance,blood perfusion and thermal insulation effects of gases,thereby considerably boosting the efficiency and reach of subsequent RFA.Interventional Physician Branch of Shanghai Medical Doctor Association,the Solid Tumor Theranostics Committee of the Shanghai Anti-Cancer Association,Chinese Anti-Cancer Association Committee of Tumor Minimally Invasive Therapy and the Innovative and Translational Consortium for Tumor Multi-Modal Minimally Invasive Diagnosis and Treatment of Chinese Society of Biomedical Engineering organized relevanted experts in the field of tumor treatment in China to discuss and formulated this expert consensus,in order to standardize the procedures of multimodal ablation therapy for pulmonary tumors and enhance therapeutic effectiveness.

Objective To explore the efficacy of extracting biopsy needle pose in chest CT images based on point cloud processing.Methods Three-dimensional point clouds were generated through segmentation of chest CT images and surface reconstruction.Spatial point cloud clustering and geometric constraints were applied to filter regions contained the puncture needle in space.The principal direction of the needle was judged using principal component analysis,and a cylindrical model was constructed to enclose the needle data.Then random sample consensus algorithm was used for needle trajectory fitting to accurately extract the spatial position and orientation of the puncture needle.The efficacy of the above method was evaluated using a 3D-printed anatomical model based on common clinical combinations of puncture depths and angles.Results The anatomical model experiments showed a 100％success rate in puncture needle identification,with angular error of(1.013±0.424)° and positional error of(2.023±1.553)mm,indicating that this method had good accuracy and stability.Conclusion The puncture needle's position in chest CT images could be extracted with high precision based on point cloud processing.