scholarly journals Accuracy evaluation of a 3D-printed individual template for needle guidance in head and neck brachytherapy

2016 ◽  
Vol 57 (6) ◽  
pp. 662-667 ◽  
Author(s):  
Ming-Wei Huang ◽  
Jian-Guo Zhang ◽  
Lei Zheng ◽  
Shu-Ming Liu ◽  
Guang-Yan Yu
Keyword(s):  
Head And Neck ◽  
Needle Insertion ◽  
Accuracy Evaluation ◽  
Angular Deviation ◽  
3D Printed ◽  
Radioactive Seeds ◽  
The Mean ◽  
125I Radioactive Seeds ◽  
Time Required

Abstract To transfer the preplan for the head and neck brachytherapy to the clinical implantation procedure, a preplan-based 3D-printed individual template for needle insertion guidance had previously been designed and used. The accuracy of needle insertion using this kind template was assessed in vivo. In the study, 25 patients with head and neck tumors were implanted with 125I radioactive seeds under the guidance of the 3D-printed individual template. Patients were divided into four groups based on the site of needle insertion: the parotid and masseter region group (nine patients); the maxillary and paranasal region group (eight patients); the submandibular and upper neck area group (five patients); and the retromandibular region group (six patients). The distance and angular deviations between the preplanned and placed needles were compared, and the complications and time required for needle insertion were assessed. The mean entrance point distance deviation for all 619 needles was 1.18 ± 0.81 mm, varying from 0.857 ± 0.545 to 1.930 ± 0.843 mm at different sites. The mean angular deviation was 2.08 ± 1.07 degrees, varying from 1.85 ± 0.93 to 2.73 ± 1.18 degrees at different sites. All needles were manually inserted to their preplanned positions in a single attempt, and the mean time to insert one needle was 7.5 s. No anatomical complications related to inaccurately placed implants were observed. Using the 3D-printed individual template for the implantation of 125I radioactive seeds in the head and neck region can accurately transfer a CT-based preplan to the brachytherapy needle insertion procedure. Moreover, the addition of individual template guidance can reduce the time required for implantation and minimize the damage to normal tissues.

scholarly journals Comparison of implant placement accuracy in two different preoperative digital workflows: navigated vs. pilot-drill-guided surgery

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Johannes Spille ◽  
Feilu Jin ◽  
Eleonore Behrens ◽  
Yahya Açil ◽  
Jürgen Lichtenstein ◽  
...  
Keyword(s):  
Navigation System ◽  
Entry Point ◽  
Angular Deviation ◽  
Guided Surgery ◽  
Implant Placement ◽  
Drill Guide ◽  
Navigation Group ◽  
3D Printed ◽  
The Mean ◽  
Master Model

Abstract Background The aim of the study is to evaluate the accuracy of a new implant navigation system on two different digital workflows. Methods A total of 18 phantom jaws consisting of hard and non-warping plastic and resembling edentulous jaws were used to stimulate a clinical circumstance. A conventional pilot-drill guide was conducted by a technician, and a master model was set by using this laboratory-produced guide. After cone beam computed tomography (CBCT) and 3D scanning of the master models, two different digital workflows (marker tray in CBCT and 3D-printed tray) were performed based on the Digital Imaging Communication in Medicine files and standard tessellation language files. Eight Straumann implants (4.1 mm × 10 mm) were placed in each model, six models for each group, resulting in 144 implant placements in total. Postoperative CBCT were taken, and deviations at the entry point and apex as well as angular deviations were measured compared to the master model. Results The mean total deviations at the implant entry point for MTC (marker tray in CBCT), 3dPT (3d-printed tray), and PDG (pilot-drill guide) were 1.024 ± 0.446 mm, 1.027 ± 0.455 mm, and 1.009 ± 0.415 mm, respectively, and the mean total deviations at the implant apex were 1.026 ± 0.383 mm, 1.116 ± 0.530 mm, and 1.068 ± 0.384 mm. The angular deviation for the MTC group was 2.22 ± 1.54°. The 3dPT group revealed an angular deviation of 1.95 ± 1.35°, whereas the PDG group showed a mean angular deviation of 2.67 ± 1.58°. Although there were no significant differences among the three groups (P > 0.05), the navigation groups showed lesser angular deviations compared to the pilot-drill-guide (PDG) group. Implants in the 3D-printed tray navigation group showed higher deviations at both entry point and apex. Conclusions The accuracy of the evaluated navigation system was similar with the accuracy of a pilot-drill guide. Accuracy of both preoperative workflows (marker tray in CBCT or 3D-printed tray) was reliable for clinical use.

In-Vivo Obstetric Pressure Measurements for Patient-Specific Epidural Simulator

2014 ◽  
Author(s):  
Neil Vaughan ◽  
Venketesh N. Dubey ◽  
Michael Y. K. Wee ◽  
Richard Isaacs
Keyword(s):  
Needle Insertion ◽  
Epidural Needle ◽  
Patient Specific ◽  
Pressure Measurements ◽  
Epidural Pressure ◽  
Loss Of Resistance ◽  
New Finding ◽  
The Mean ◽  
Thickness Measurements

The aim of this study was to measure changing pressures during Tuohy epidural needle insertions for obstetric parturients of various BMI. This has identified correlations between BMI and epidural pressure. Also we investigated links between BMI and the thicknesses and depths of ligaments and epidural space as measured from MRI and ultrasound scans. To date there have been no studies relating epidural pressure and ligament thickness changes with varying Body Mass Indices (BMI). Further goals following measurement of pressure differences between various BMI patients, were to allow a patient-specific epidural simulator to be developed, which has not been achieved before. The trial has also assessed the suitability of our in-house developed wireless pressure measurement device for use in-vivo. Previously we conducted needle insertion trial with porcine for validation of the measurement system. Results showed that for each group average pressures during insertion decrease as BMI increases. Pressure measurements obtained from the patients were matched to tissue thickness measurements from MRI and ultrasound scans. The mean Loss of Resistance (LOR) pressure in each group reduces as BMI increases. Variation in the shape of the pressure graphs was noticed between two epiduralists performing the procedure, suggesting each anaesthetist may have a signature graph shape. This is a new finding which offers potential use in epidural training and assessment. It can be seen that insertions performed by the first epiduralist have a higher pressure range than insertions performed by second epiduralist.

scholarly journals Robotic CT-guided out-of-plane needle insertion: comparison of angle accuracy with manual insertion in phantom and measurement of distance accuracy in animals

2019 ◽  
Vol 30 (3) ◽  
pp. 1342-1349 ◽  
Author(s):  
Toshiyuki Komaki ◽  
Takao Hiraki ◽  
Tetsushi Kamegawa ◽  
Takayuki Matsuno ◽  
Jun Sakurai ◽  
...  
Keyword(s):  
Animal Experiment ◽  
Animal Experiments ◽  
Smartphone Application ◽  
Needle Insertion ◽  
Phantom Experiment ◽  
Ct Guided ◽  
Key Points ◽  
Out Of Plane ◽  
The Mean

Abstract Objectives To evaluate the accuracy of robotic CT-guided out-of-plane needle insertion in phantom and animal experiments. Methods A robotic system (Zerobot), developed at our institution, was used for needle insertion. In the phantom experiment, 12 robotic needle insertions into a phantom at various angles in the XY and YZ planes were performed, and the same insertions were manually performed freehand, as well as guided by a smartphone application (SmartPuncture). Angle errors were compared between the robotic and smartphone-guided manual insertions using Student’s t test. In the animal experiment, 6 robotic out-of-plane needle insertions toward targets of 1.0 mm in diameter placed in the kidneys and hip muscles of swine were performed, each with and without adjustment of needle orientation based on reconstructed CT images during insertion. Distance accuracy was calculated as the distance between the needle tip and the target center. Results In the phantom experiment, the mean angle errors of the robotic, freehand manual, and smartphone-guided manual insertions were 0.4°, 7.0°, and 3.7° in the XY plane and 0.6°, 6.3°, and 0.6° in the YZ plane, respectively. Robotic insertions in the XY plane were significantly (p < 0.001) more accurate than smartphone-guided insertions. In the animal experiment, the overall mean distance accuracy of robotic insertions with and without adjustment of needle orientation was 2.5 mm and 5.0 mm, respectively. Conclusion Robotic CT-guided out-of-plane needle insertions were more accurate than smartphone-guided manual insertions in the phantom and were also accurate in the in vivo procedure, particularly with adjustment during insertion. Key Points • Out-of-plane needle insertions performed using our robot were more accurate than smartphone-guided manual insertions in the phantom experiment and were also accurate in the in vivo procedure. • In the phantom experiment, the mean angle errors of the robotic and smartphone-guided manual out-of-plane needle insertions were 0.4° and 3.7° in the XY plane (p < 0.001) and 0.6° and 0.6° in the YZ plane (p = 0.65), respectively. • In the animal experiment, the overall mean distance accuracies of the robotic out-of-plane needle insertions with and without adjustments of needle orientation during insertion were 2.5 mm and 5.0 mm, respectively.

scholarly journals Analytical Review: The Kinetics of Granulopoiesis in Normal Man

Blood ◽  
1964 ◽  
Vol 24 (6) ◽  
pp. 780-803 ◽  
Author(s):  
G. E. CARTWRIGHT ◽  
J. W. ATHENS ◽  
M. M. WINTROBE
Keyword(s):  
Body Weight ◽  
Generation Time ◽  
Turnover Time ◽  
Normal Male ◽  
The Mean ◽  
Time Required ◽  
Kinetics Of ◽  
Male Subjects

Abstract Present knowledge concerning the kinetics of granulopoiesis has been reviewed and quantitative data concerning granulokinetics in normal human subjects are presented. A. When granulocytes are labeled in vitro and returned to the circulation of the donor, the distribution of the cells in the circulation and the rate of disappearance of the cells from the circulation can be measured. 1. The total blood granulocyte pool (TBGP) consists of two compartments which are in equilibrium with each other. These pools have been designated the circulating granulocyte pool (CGP) and the marginal granulocyte pool (MGP). The size of the pools has been measured in 109 normal male subjects. The mean values, expressed as numbers of cells x 107 per Kg. of body weight were as follows: TBGP, 70; CGP, 31; and MGP, 39. The mean ratio of the CGP to the TBGP was 0.44. 2. The labeled granulocytes leave the TBGP in an exponential fashion with a mean half-time disappearance (T½) of 6.7 hours as determined in 56 normal male subjects. No evidence has been obtained for a return of granulocytes to the blood. 3. The mean value for the granulocyte turnover rate (GTR) in 56 normal male subjects was 163 x 107 granulocytes per Kg. of body weight per day. Thus, the TBGP turns over 2.3 times per day and the turnover time for the TBGP is 10.4 hours. B. When granulocytes are labeled in vivo by the intravenous administration of DFP32, the rate of disappearance of granulocytes from the circulation and the time required for myelocytes to divide, mature and appear in the blood can be measured. In addition, the generation time of myelocytes can be approximated. From the time parameters and the GTR, the bone marrow pool sizes and turnover times can be calculated. These determinations and calculations have been made for a group of 21 normal male subjects. 1. The mean half-time disappearance (T½) of in vivo labeled granulocytes from the circulation was 7.2 hours. This value agrees well with the value of 6.7 hours obtained after the in vitro labeling of granulocytes. 2. The mean time required for myelocytes to divide, mature and appear in the blood was 11.4 days. 3. The mean generation time of myelocytes was estimated to be not more than 2.9 days. 4. The total granulocyte pool in the bone marrow (neutrophilic myelocytes, neutrophilic metamyelocytes and PMN neutrophils) was calculated to be 186 x 108 cells per Kg. of body weight with a mean turnover time of 11.4 days. The myelocyte pool was estimated to be 41 x 108 cells per Kg. with a turnover time of 2.5 days; the metamyelocyte pool consisted of about 76 x 108 cells per Kg. with a turnover time of 4.7 days; the average size of the mature marrow PMN neutrophil pool was 69 x 108 cells per Kg. of body weight with a turnover time of 4.2 days. C. A kinetic model for granulopoiesis, based on the studies with the DFP32 label, is presented. In this model, myelocytes are depicted as approaching a self-perpetuating population of cells. Some cells enter this population from populations which are less mature but this latter source of cells is small under conditions of normal steady state kinetics. One of the daughter cells of a myelocyte division remains in the myelocyte population to divide again. The other daughter cell enters the metamyelocyte population. The metamyelocyte and PMN neutrophil population is incapable of division and cells move through this population in sequential fashion in the process of maturation. The cells then enter the blood where they equilibrate rapidly between the two blood compartments. The cells are removed from the total granulocyte pool in a random fashion. There is no appreciable pool of granulocytes in the extramedullary tissues of normal subjects and granulocytes do not return from the tissues to the blood. The entire movement of granulocytes from marrow to tissues is uni-directional.

scholarly journals Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders

2020 ◽  
pp. 20200313
Author(s):  
Antônio Luís Neto Custódio ◽  
Andrew Cameron ◽  
Mahmoud Bakr ◽  
Chris Little ◽  
Bruno Ramos Chrcanovic ◽  
...  
Keyword(s):  
Accuracy Assessment ◽  
Mean Difference ◽  
Virtual Planning ◽  
Percutaneous Injection ◽  
Mean Values ◽  
Surgical Guide ◽  
Injection Techniques ◽  
3D Printed ◽  
The Mean

Objective: The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). Methods: Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. Results: The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82–2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94–2.03 mm). Conclusion: The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

Assay of canine profibrinolysin (plasminogen)

1959 ◽  
Vol 197 (2) ◽  
pp. 391-395 ◽  
Author(s):  
D. R. Celander ◽  
M. Mason Guest
Keyword(s):  
Unit Activity ◽  
Fibrinolytic Activity ◽  
Fibrin Clot ◽  
Protamine Sulfate ◽  
Assay Method ◽  
Plasma Samples ◽  
The Mean ◽  
Time Required

An assay method for canine profibrinolysin is outlined and unit activity defined. In this assay profibrinolysin, concentrated in a precipitate obtained by dilution of protamine sulfate-treated plasma, is activated with staphylokinase. The fibrinolytic activity generated is then measured by the time required for lysis of a standard bovine fibrin clot. The mean profibrinolysin titer of plasma samples from 121 control animals is 19.4 u. Increased fibrinolytic activity induced in vivo by various experimental procedures is found to be associated with decreased profibrinolysin titers.

scholarly journals Acoustic and Aerodynamic Coupling during Phonation in MRI-Based Vocal Tract Replicas

2019 ◽  
Vol 9 (17) ◽  
pp. 3562
Author(s):  
Judith Probst ◽  
Alexander Lodermeyer ◽  
Sahar Fattoum ◽  
Stefan Becker ◽  
Matthias Echternach ◽  
...  
Keyword(s):  
Cross Sections ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Aerodynamic Characteristics ◽  
Fluid Structure ◽  
Acoustic Interaction ◽  
Voiced Speech ◽  
3D Printed ◽  
The Mean

Voiced speech is the result of a fluid-structure-acoustic interaction in larynx and vocal tract (VT). Previous studies show a strong influence of the VT on this interaction process, but are limited to individually obtained VT geometries. In order to overcome this restriction and to provide a more general VT replica, we computed a simplified, averaged VT geometry for the vowel /a/. The basis for that were MRI-derived cross-sections along the straightened VT centerline of six professional tenors. The resulting mean VT replica, as well as realistic and simplified VT replicas of each tenor were 3D-printed for experiments with silicone vocal folds that show flow-induced oscillations. Our results reveal that all replicas, including the mean VT, reproduce the characteristic formants with mean deviations of 12% when compared with the subjects’ audio recordings. The overall formant structure neither is impaired by the averaging process, nor by the simplified geometry. Nonetheless, alterations in the broadband, non-harmonic portions of the sound spectrum indicate changed aerodynamic characteristics within the simplified VT. In conclusion, our mean VT replica shows similar formant properties as found in vivo. This indicates that the mean VT geometry is suitable for further investigations of the fluid-structure-acoustic interaction during phonation.

Comparison of in vivo and in vitro prostaglandin E production by squamous cell carcinoma of the head and neck

1994 ◽  
Vol 111 (3) ◽  
pp. 189-196 ◽  
Author(s):  
C SNYDERMAN ◽  
I KLAPAN ◽  
M MILANOVICH ◽  
D HEO ◽  
R WAGNER ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Head And Neck ◽  
Squamous Cell ◽  
Prostaglandin E

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

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