The additive manufacturing(AM)process plays an important role in enabling cross-disciplinary research in engineering and personalised medicine.Commercially available clinical tools currently utilised in radiotherapy a...The additive manufacturing(AM)process plays an important role in enabling cross-disciplinary research in engineering and personalised medicine.Commercially available clinical tools currently utilised in radiotherapy are typically based on traditional manufacturing processes,often leading to non-conformal geometries,time-consuming manufacturing process and high costs.An emerging application explores the design and development of patient-specific clinical tools using AM to optimise treatment outcomes among cancer patients receiving radiation therapy.In this review,we:•highlight the key advantages of AM in radiotherapy where rapid prototyping allows for patient-specific manufacture•explore common clinical workflows involving radiotherapy tools such as bolus,compensators,anthropomorphic phantoms,immobilisers,and brachytherapy moulds;and•investigate how current AM processes are exploited by researchers to achieve patient tissuelike imaging and dose attenuations.Finally,significant AM research opportunities in this space are highlighted for their future advancements in radiotherapy for diagnostic and clinical research applications.展开更多
BACKGROUND Recently,a technique has been developed to use magnetic resonance enterography(MRE)for the evaluation of small bowel motility.The hypothesis was that assessment of the motility index(MI)should reflect diffe...BACKGROUND Recently,a technique has been developed to use magnetic resonance enterography(MRE)for the evaluation of small bowel motility.The hypothesis was that assessment of the motility index(MI)should reflect differences in motility between clinical conditions.AIM To aim of the present observational,cross-sectional study was to evaluate the use of the MI in daily clinical practice.METHODS All consecutive patients aged 18-70 years who were referred for MRE at the Department of Radiology during a 2-year period were asked to participate.Healthy volunteers were included as controls.MRE was prepared and conducted in accordance with clinical routines.On the day of examination,all the participants had to complete the visual analog scale for irritable bowel syndrome(IBS)and IBS-symptom severity scale.Maps of MI were calculated from dynamic MR images.ANOVA was used to evaluate differences in MI between groups,classified as healthy,Crohn’s disease,ulcerative colitis,IBS,other assorted disorders and dysmotility.Logistic and linear regression were applied to the MI values.All medical records were scrutinized for medical history.RESULTS In all,224 examinations were included(inclusion prevalence 76.3%),with 22 controls and 202 patients.There was a significant difference in the MI of the jejunum(P=0.021)and terminal ileum(P=0.007)between the different groups.The MI was inversely associated with the mural thickness of the terminal ileum in men(P<0.001)and women(P=0.063)after adjustments,and tended to be lower in men than in women(P=0.056).Subjectively observed reduction of motility on MRI was accomplished by reduced MI of terminal ileum in men(P<0.001)and women(P=0.030).In women,diarrhea was inversely associated with the MI of the jejunum(P=0.029),and constipation was positively associated with the MI of the terminal ileum(P=0.039).CONCLUSION Although MIs differ across diseases,a lower MI of the terminal ileum is mainly associated with male sex and an increased mural thickness.Symptoms are weakly associated with the MI.展开更多
BACKGROUND The enteric nervous system(ENS)is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines.The ENS consists of neurons,glial c...BACKGROUND The enteric nervous system(ENS)is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines.The ENS consists of neurons,glial cells,and nerves assembled into ganglia,surrounded by telocytes,interstitial cells of Cajal,and connective tissue.Owing to the complex spatial organization of several interconnections with nerve fascicles,the ENS is difficult to examine in conventional histological sections of 3-5μm.AIM To examine human ileum full-thickness biopsies using X-ray phase-contrast nanotomography without prior staining to visualize the ENS.METHODS Six patients were diagnosed with gastrointestinal dysmotility and neuropathy based on routine clinical and histopathological examinations.As controls,fullthickness biopsies were collected from healthy resection ileal regions after hemicolectomy for right colon malignancy.From the paraffin blocks,4-μm thick sections were prepared and stained with hematoxylin and eosin for localization of the myenteric ganglia under a light microscope.A 1-mm punch biopsy(up to 1 cm in length)centered on the myenteric plexus was taken and placed into a Kapton®tube for mounting in the subsequent investigation.X-ray phase-contrast tomography was performed using two custom-designed laboratory setups with micrometer resolution for overview scanning.Subsequently,selected regions of interest were scanned at a synchrotron-based end-station,and high-resolution slices were reported.In total,more than 6000 virtual slices were analyzed from nine samples.RESULTS In the overview scans,the general architecture and quality of the samples were studied,and the myenteric plexus was localized.High-resolution scans revealed details,including the ganglia,interganglional nerve fascicles,and surrounding tissue.The ganglia were irregular in shape and contained neurons and glial cells.Spindle-shaped cells with very thin cellular projections could be observed on the surface of the ganglia,which appeared to build a network.In the patients,there were no alterations in the general architecture of the myenteric ganglia.Nevertheless,several pathological changes were observed,including vacuolar degeneration,autophagic activity,the appearance of sequestosomes,chromatolysis,and apoptosis.Furthermore,possible expulsion of pyknotic neurons and defects in the covering cellular network could be observed in serial slices.These changes partly corresponded to previous light microscopy findings.CONCLUSION The analysis of serial virtual slices could provide new information that cannot be obtained by classical light microscopy.The advantages,disadvantages,and future possibilities of this method are also discussed.展开更多
Global cerebral perfusion parameters were measured using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in eight healthy volunteers examined during normal breathing and spontaneous hyperventilati...Global cerebral perfusion parameters were measured using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in eight healthy volunteers examined during normal breathing and spontaneous hyperventilation. DSC-MRI-based cerebral blood flow (CBF) de-creased during hyperventilation in all volun-teers (average decrease 29%), and the corre-sponding global CBF estimates were 73±19ml/ (min100g) during normal breathing and 52± 7.9ml/(min100g) during hyperventilation (mean ±SD, n=8). Furthermore, the hypocapnic condi-tions induced by hyperventilation resulted in a prolongation of the global mean transit time (MTT) by on average 14%. The observed CBF estimates appeared to be systematically over-estimated, in accordance with previously pub-lished DSC-MRI results, but reduced to more reasonable levels when a previously retrieved calibration factor was applied.展开更多
Purpose: To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from ...Purpose: To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from 20 - 400 s/mm2 were designed with identical parameters but with different handling of respiratory motion [respiratory triggered (RT), free breathing (FB), breath hold (BH)] on 3 T and 1.5 T. Thirteen volunteers were examined at a 3 T and six of them also at a 1.5 T magnet. DW images were analyzed quantitatively and qualitatively. Regions of interest were placed in cranial, middle and caudal parts of the right liver lobe (RLL) and ADC and SNR were calculated. Results: ADC in RLL tended to be lower at 3 T MRI. Least inter-subject ADC variability was found with RT in the middle RLL at 3 T. Highest ADCs were found caudally in the RLL. Significant differences in ADC between middle and caudal RLL were calculated in FB and RT at 3 T and FB and BH at 1.5 T, respectively. No significant difference in SNR was found between 3 T and 1.5 T. There were significantly more artifacts in the left liver lobe (LLL) compared to the RLL in all sequences and in the LLL at 3 T compared to 1.5 T. Conclusion: Our study suggests that longitudinal hepatic ADC measurements should be performed using equivalent field strength, b-values, and acquisition technique, given influence of these factors on ADC measurements.展开更多
Delivering pharmacologic agents directly into the brain has been proposed as a means of bypassing the blood brain barrier.However,despite 16 years of research on a number of central nervous system disorders,an effecti...Delivering pharmacologic agents directly into the brain has been proposed as a means of bypassing the blood brain barrier.However,despite 16 years of research on a number of central nervous system disorders,an effective treatment using this strategy has only been observed in the brain tumor glioblastoma multiforme.Within this study we propose a novel system for delivering drugs into the brain named the simple diffusion (SDD) system.To validate this technique,rats were subjected to a single intracranial (at the caudate nucleus),or intraperitoneal injection,of the compound citicoline,followed two hours later by a permanent middle cerebral artery occlusion (pMCAO).Results showed that 12 h after pMCAO,with 0.0025 g kg-1 citicoline,an infarct volume 1/6 the size of the intraperitoneal group was achieved with a dose 1/800 of that required for the intraperitoneal group.These results suggest that given the appropriate injection point,through SDD a pharmacologically effective concentration of citicoline can be administered.展开更多
Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not y...Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not yet routinely applied because their degradation behavior is not fully understood.In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium(Gd)at high resolution.Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4,8 and 12 weeks.Afterward,the degradation rate and degradation homogeneity,as well as bone-to-implant interface,were studied with synchrotron radiation micro computed tomography and histology.Titanium(Ti)and polyether ether ketone(PEEK)were used as controls material to evaluate osseointegration.Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd.Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue.The results were correlated to in vitro data obtained from the same material and shape.The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK.The results suggest that both Mg-xGd alloys are suitable as materials for bone implants.展开更多
基金This research was conducted by the Australian Research Council Industrial Transformation Training Centre in Additive Biomanufacturing(IC160100026).The support of the Gross Foundation is also acknowledged.
文摘The additive manufacturing(AM)process plays an important role in enabling cross-disciplinary research in engineering and personalised medicine.Commercially available clinical tools currently utilised in radiotherapy are typically based on traditional manufacturing processes,often leading to non-conformal geometries,time-consuming manufacturing process and high costs.An emerging application explores the design and development of patient-specific clinical tools using AM to optimise treatment outcomes among cancer patients receiving radiation therapy.In this review,we:•highlight the key advantages of AM in radiotherapy where rapid prototyping allows for patient-specific manufacture•explore common clinical workflows involving radiotherapy tools such as bolus,compensators,anthropomorphic phantoms,immobilisers,and brachytherapy moulds;and•investigate how current AM processes are exploited by researchers to achieve patient tissuelike imaging and dose attenuations.Finally,significant AM research opportunities in this space are highlighted for their future advancements in radiotherapy for diagnostic and clinical research applications.
基金the Development Foundation of Region Skåne,No.REGSKANE-619091the Foundation of Skåne University Hospital,No.2017-008and the Dir Albert Påhlsson’s Foundation,No.2019.
文摘BACKGROUND Recently,a technique has been developed to use magnetic resonance enterography(MRE)for the evaluation of small bowel motility.The hypothesis was that assessment of the motility index(MI)should reflect differences in motility between clinical conditions.AIM To aim of the present observational,cross-sectional study was to evaluate the use of the MI in daily clinical practice.METHODS All consecutive patients aged 18-70 years who were referred for MRE at the Department of Radiology during a 2-year period were asked to participate.Healthy volunteers were included as controls.MRE was prepared and conducted in accordance with clinical routines.On the day of examination,all the participants had to complete the visual analog scale for irritable bowel syndrome(IBS)and IBS-symptom severity scale.Maps of MI were calculated from dynamic MR images.ANOVA was used to evaluate differences in MI between groups,classified as healthy,Crohn’s disease,ulcerative colitis,IBS,other assorted disorders and dysmotility.Logistic and linear regression were applied to the MI values.All medical records were scrutinized for medical history.RESULTS In all,224 examinations were included(inclusion prevalence 76.3%),with 22 controls and 202 patients.There was a significant difference in the MI of the jejunum(P=0.021)and terminal ileum(P=0.007)between the different groups.The MI was inversely associated with the mural thickness of the terminal ileum in men(P<0.001)and women(P=0.063)after adjustments,and tended to be lower in men than in women(P=0.056).Subjectively observed reduction of motility on MRI was accomplished by reduced MI of terminal ileum in men(P<0.001)and women(P=0.030).In women,diarrhea was inversely associated with the MI of the jejunum(P=0.029),and constipation was positively associated with the MI of the terminal ileum(P=0.039).CONCLUSION Although MIs differ across diseases,a lower MI of the terminal ileum is mainly associated with male sex and an increased mural thickness.Symptoms are weakly associated with the MI.
基金Supported by the Development Foundation of Region Skane,No.REGSKANE-818781 and No.2018-Projekt0024the Foundation Skane University Hospital,No.2020-0000028.
文摘BACKGROUND The enteric nervous system(ENS)is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines.The ENS consists of neurons,glial cells,and nerves assembled into ganglia,surrounded by telocytes,interstitial cells of Cajal,and connective tissue.Owing to the complex spatial organization of several interconnections with nerve fascicles,the ENS is difficult to examine in conventional histological sections of 3-5μm.AIM To examine human ileum full-thickness biopsies using X-ray phase-contrast nanotomography without prior staining to visualize the ENS.METHODS Six patients were diagnosed with gastrointestinal dysmotility and neuropathy based on routine clinical and histopathological examinations.As controls,fullthickness biopsies were collected from healthy resection ileal regions after hemicolectomy for right colon malignancy.From the paraffin blocks,4-μm thick sections were prepared and stained with hematoxylin and eosin for localization of the myenteric ganglia under a light microscope.A 1-mm punch biopsy(up to 1 cm in length)centered on the myenteric plexus was taken and placed into a Kapton®tube for mounting in the subsequent investigation.X-ray phase-contrast tomography was performed using two custom-designed laboratory setups with micrometer resolution for overview scanning.Subsequently,selected regions of interest were scanned at a synchrotron-based end-station,and high-resolution slices were reported.In total,more than 6000 virtual slices were analyzed from nine samples.RESULTS In the overview scans,the general architecture and quality of the samples were studied,and the myenteric plexus was localized.High-resolution scans revealed details,including the ganglia,interganglional nerve fascicles,and surrounding tissue.The ganglia were irregular in shape and contained neurons and glial cells.Spindle-shaped cells with very thin cellular projections could be observed on the surface of the ganglia,which appeared to build a network.In the patients,there were no alterations in the general architecture of the myenteric ganglia.Nevertheless,several pathological changes were observed,including vacuolar degeneration,autophagic activity,the appearance of sequestosomes,chromatolysis,and apoptosis.Furthermore,possible expulsion of pyknotic neurons and defects in the covering cellular network could be observed in serial slices.These changes partly corresponded to previous light microscopy findings.CONCLUSION The analysis of serial virtual slices could provide new information that cannot be obtained by classical light microscopy.The advantages,disadvantages,and future possibilities of this method are also discussed.
文摘Global cerebral perfusion parameters were measured using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in eight healthy volunteers examined during normal breathing and spontaneous hyperventilation. DSC-MRI-based cerebral blood flow (CBF) de-creased during hyperventilation in all volun-teers (average decrease 29%), and the corre-sponding global CBF estimates were 73±19ml/ (min100g) during normal breathing and 52± 7.9ml/(min100g) during hyperventilation (mean ±SD, n=8). Furthermore, the hypocapnic condi-tions induced by hyperventilation resulted in a prolongation of the global mean transit time (MTT) by on average 14%. The observed CBF estimates appeared to be systematically over-estimated, in accordance with previously pub-lished DSC-MRI results, but reduced to more reasonable levels when a previously retrieved calibration factor was applied.
文摘Purpose: To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from 20 - 400 s/mm2 were designed with identical parameters but with different handling of respiratory motion [respiratory triggered (RT), free breathing (FB), breath hold (BH)] on 3 T and 1.5 T. Thirteen volunteers were examined at a 3 T and six of them also at a 1.5 T magnet. DW images were analyzed quantitatively and qualitatively. Regions of interest were placed in cranial, middle and caudal parts of the right liver lobe (RLL) and ADC and SNR were calculated. Results: ADC in RLL tended to be lower at 3 T MRI. Least inter-subject ADC variability was found with RT in the middle RLL at 3 T. Highest ADCs were found caudally in the RLL. Significant differences in ADC between middle and caudal RLL were calculated in FB and RT at 3 T and FB and BH at 1.5 T, respectively. No significant difference in SNR was found between 3 T and 1.5 T. There were significantly more artifacts in the left liver lobe (LLL) compared to the RLL in all sequences and in the LLL at 3 T compared to 1.5 T. Conclusion: Our study suggests that longitudinal hepatic ADC measurements should be performed using equivalent field strength, b-values, and acquisition technique, given influence of these factors on ADC measurements.
基金supported by the National Natural Science Foundation of China(Grant Nos. 30972811 and 81071148)Natural Science Foundation of Beijing(Grant No. 7093137)
文摘Delivering pharmacologic agents directly into the brain has been proposed as a means of bypassing the blood brain barrier.However,despite 16 years of research on a number of central nervous system disorders,an effective treatment using this strategy has only been observed in the brain tumor glioblastoma multiforme.Within this study we propose a novel system for delivering drugs into the brain named the simple diffusion (SDD) system.To validate this technique,rats were subjected to a single intracranial (at the caudate nucleus),or intraperitoneal injection,of the compound citicoline,followed two hours later by a permanent middle cerebral artery occlusion (pMCAO).Results showed that 12 h after pMCAO,with 0.0025 g kg-1 citicoline,an infarct volume 1/6 the size of the intraperitoneal group was achieved with a dose 1/800 of that required for the intraperitoneal group.These results suggest that given the appropriate injection point,through SDD a pharmacologically effective concentration of citicoline can be administered.
基金This research was carried out within the SynchroLoad project(BMBF project number 05K16CGA)which is funded by the Rontgen-Ångstrom Cluster(RÅC)a bilateral research collaboration of the Swedish government and the German Federal Ministry of Education and Research(BMBF)+1 种基金We also acknowledge the project MgBone(BMBF project number 05K16CGB)Swedish Research Council 2015-06109.Additionally,we acknowledge provision of beamtime by PETRA III DESY within the long-term Proposal II-20170009 and beamtimes related to following IDs:11001978,11003288,11003440,11003773,11003950,11004016,11004263,11005553,and 11005842。
文摘Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not yet routinely applied because their degradation behavior is not fully understood.In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium(Gd)at high resolution.Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4,8 and 12 weeks.Afterward,the degradation rate and degradation homogeneity,as well as bone-to-implant interface,were studied with synchrotron radiation micro computed tomography and histology.Titanium(Ti)and polyether ether ketone(PEEK)were used as controls material to evaluate osseointegration.Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd.Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue.The results were correlated to in vitro data obtained from the same material and shape.The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK.The results suggest that both Mg-xGd alloys are suitable as materials for bone implants.
