Different Types Of Needles Research Articles

Effect of Apical Preparation on Different Needle Depth Penetration.

Introduction: Irrigation is a fundamental part of endodontic debridement as because it allows for cleaning beyond what might be accomplished by root canal instrumentation. The flushing action produced by the irrigant and the penetration of the irrigant is not dependent only on the anatomy of the root canal system, but also on the depth of placement, system of delivery, the volume and fluid properties of the irrigant. Aim: The aim of the study was to evaluate the effect of apical preparation on the penetration depth of different types of needles. Methods: Thirty single-rooted lower premolar teeth were involved in this study. The access opening was performed by using a round diamond bur turbine (diameter 12) and Kfiles (diameter 15) were used for initial penetration in the canal. Stereo- microscope under 20 magnifications was used to determine the working length of the canal. Then the canals were prepared using protaper next in continuos rotation according to manufacture instructions with sequence files reached the WL (X1, X2, X3, X4). 4 mL of 5.25% NaOCI was used between each instrument. Three different types of endodontic needles were used. Needles size 27, 30-gauge stainless steel and IRRIFLEX endodontic irrigation needle. Each needle was inserted in the canal and its length of penetration was measured before canal preparation and after finishing files then the depth of penetration was measured. Results: ANOVA test showed that there are significant differences among all groups also results show a significant difference when comparing 27 with 30 needle gauge irriflex but there was no significant difference between the needle gauge 30 and irriflex. Conclusion: This study shows that the penetration depth of needles influences on apical preparation it appears that 27 -gauge needles show less depth penetration when compared to irriflex and 30- gauge needles. Keywords: apical, needle, penetration depth, endodontics.

Mechanical and shape memory properties of Eucommia ulmoides gum-based elastic fibers with various architectures

Eucommia ulmoides gum (EUG) is composed of trans-1,4-polyisoprene with high flexibility and crystallinity, and could be utilized as elastic and thermoplastic materials. Taking advantage of the unique crystallization characteristics, a series of EUG-based complex elastic fibers were prepared by wet-spinning method using different types of needles. It was found that the EUG fiber displayed excellent mechanical properties including high tensile strength (42.8 MPa), elongation at break (572%), and toughness (136.8 MJ m−3). The complex elastic fibers combining different compositions and various architectures have higher temperature sensitivity and excellent shape memory recovery ability compared to EUG elastomer. Meanwhile, the elastic fibers containing EUG and butyl rubber (IIR) exhibited better damping properties than pristine EUG. Therefore, this work provided a way to enhance the functionality and expand the application of bio-based EUG materials.

Feasibility and safety of ultrasound-guided percutaneous transhepatic measurement of portal venous pressure.

The measurement of portal venous pressure (PVP) has been extensively studied, primarily through indirect methods. However, the potential of ultrasound-guided percutaneous transhepatic PVP measurement as a direct method has been largely unexplored. This study aimed to investigate the accuracy, safety, and feasibility of this approach. In vitro, the experiment aimed to select a needle that could accurately transmit pressure, had a small inner diameter and was suitable for liver puncture, and performed on 20 healthy New Zealand white rabbits. An ultrasound-guided percutaneous transhepatic portal vein puncture was undertaken to measure PVP. Additionally, free hepatic venous pressure (FHVP) and wedged hepatic venous pressure (WHVP) were measured under digital subtraction angiography (DSA). The correlation between the two methods was assessed. Enroll study participants from October 18, 2023 to November 11, 2023 with written informed consent. Five patients were measured the PVP under ultrasound guidance before surgery to determine the feasibility of this measurement method. There was no significant difference in the results obtained using 9 different types of needles (P > 0.05). This demonstrated a great repeatability (P < 0.05). The 22G chiba needle with small inner diameter, allowing for accurate pressure transmission and suitable for liver puncture, was utilized for percutaneous transhepatic PVP measurement. There were positive correlations between PVP and HVPG (r = 0.881), PVP and WHVP (r = 0.709), HVPG and WHVP (r = 0.729), IVCP and FHVP (r = 0.572). The PVP was accurately and safely measured in 5 patients with segmental hepatectomy. No complications could be identified during postoperative ultrasound. Percutaneous transhepatic portal venous puncture under ultrasound guidance is accurate, safe and feasible to measure portal venous pressure. This study has been registered in the Chinese Clinical Trial Registry with registration number ChiCTR2300076751.

Clinical Applications of Endobronchial Ultrasound (EBUS) Scope: Challenges and Opportunities.

Endobronchial Ultrasound (EBUS) has been widely used to stage lung tumors and to diagnose mediastinal diseases. In the last decade, this procedure has evolved in several technical aspects, with new tools available to optimize tissue sampling and to increase its diagnostic yield, like elastography, different types of needles and, most recently, miniforceps and cryobiopsy. Accordingly, the indications for the use of the EBUS scope into the airways to perform the Endobronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) has also extended beyond the endobronchial and thoracic boundaries to sample lesions from the liver, left adrenal gland and retroperitoneal lymph nodes via the gastroesophageal tract, performing the Endoscopic UltraSound with Bronchoscope-guided Fine Needle Aspiration (EUS-B-FNA). In this review, we summarize and critically discuss the main indication for the use of the EBUS scope, even the more uncommon, to underline its utility and versatility in clinical practice.

Role of endoscopic ultrasound in the characterization of solid pseudopapillary neoplasm of the pancreas.

Solid pseudopapillary neoplasm (SPN) is an uncommon pathology of the pancreas with unpredictable malignant potential. Endoscopic ultrasound (EUS) assessment plays a vital role in lesion characterization and confirmation of the tissue diagnosis. However, there is a paucity of data regarding the imaging assessment of these lesions. To determine the characteristic EUS features of SPN and define its role in preoperative assessment. This was an international, multicenter, retrospective, observational study of prospective cohorts from 7 large hepatopancreaticobiliary centers. All cases with postoperative histology of SPN were included in the study. Data collected included clinical, biochemical, histological and EUS characteristics. One hundred and six patients with the diagnosis of SPN were included. The mean age was 26 years (range 9 to 70 years), with female predominance (89.6%). The most frequent clinical presentation was abdominal pain (80/106; 75.5%). The mean diameter of the lesion was 53.7 mm (range 15 to 130 mm), with the slight predominant location in the head of the pancreas (44/106; 41.5%). The majority of lesions presented with solid imaging features (59/106; 55.7%) although 33.0% (35/106) had mixed solid/cystic characteristics and 11.3% (12/106) had cystic morphology. Calcification was observed in only 4 (3.8%) cases. Main pancreatic duct dilation was uncommon, evident in only 2 cases (1.9%), whilst common bile duct dilation was observed in 5 (11.3%) cases. One patient demonstrated a double duct sign at presentation. Elastography and Doppler evaluation demonstrated inconsistent appearances with no emergence of a predictable pattern. EUS guided biopsy was performed using three different types of needles: Fine needle aspiration (67/106; 63.2%), fine needle biopsy (37/106; 34.9%), and Sonar Trucut (2/106; 1.9%). The diagnosis was conclusive in 103 (97.2%) cases. Ninety-seven patients were treated surgically (91.5%) and the post-surgical SPN diagnosis was confirmed in all cases. During the 2-year follow-up period, no recurrence was observed. SPN presented primarily as a solid lesion on endosonographic assessment. The lesion tended to be located in the head or body of the pancreas. There was no consistent characteristic pattern apparent on either elastography or Doppler assessment. Similarly SPN did not frequently cause stricture of the pancreatic duct or common bile duct. Importantly, we confirmed that EUS-guided biopsy was an efficient and safe diagnostic tool. The needle type used does not appear to have a significant impact on the diagnostic yield. Overall SPN remains a challenging diagnosis based on EUS imaging with no pathognomonic features. EUS guided biopsy remains the gold standard in establishing the diagnosis.

Comparison of Adverse Events of Different Endoscopic Ultrasound-Guided Tissue Acquisition Methods: A Single-Center Retrospective Analysis.

The efficacy of new generation endoscopic ultrasound-guided biopsy needles has been promising in recent years. Yet, comparing these needles’ diagnostic yield and safety to conventional needles is not well-known. Our study aims to compare the adverse events of endoscopic ultrasound-guided tissue acquisition (EUS-TA) with different types of needles, including FNA needles, FNB needles with a Franseen tip and FNB needles with a reverse bevel. Furthermore, we will analyze the risk factors, including tumor vascularity, different needle types, and the underlying disease, which may impact the safety of the procedures. From May 2014 to December 2021, 192 consecutive EUS-TAs were performed on pancreatic and peripancreatic lesions in our hospital using different types of FNA and FNB needles. We retrospectively reviewed the data and identified the risk factors for EUS-TA-related complications. As a result, the hypervascular tumor is a significant risk factor for adverse events in our multivariate analysis, with an odds ratio of 4.96 (95% CI 1.33–18.47), while liver cirrhosis is one of the risk factors for adverse events during EUS-TA, with an odds ratio of 5.3 (95% CI 1.1–25.6). However, the risk of adverse events did not increase using Franseen-tip needles, compared to conventional FNA or FNB needles with a reverse bevel. In conclusion, we must be more cautious in patients with liver cirrhosis and hypervascular tumors, such as pancreatic neuroendocrine tumors, when performing EUS-guided tissue acquisition.

Reorientation technique has benefits in bone marrow aspiration of stem cells

We treated patients with osteoarthritis of the knee using injections of bone marrow aspirate concentrate (stem cell therapy). Since multiple controversial harvesting methods using different sites, needles, volumes and techniques have been described, we aimed to compare those methods. Four different harvesting sites at the iliac crest, three different types of needles, three different types of volumes and two different harvesting techniques were compared in 48 bone marrow aspirations. The conventional technique (Group 1) was compared with a reorientation technique (Group 2). The number of leucocytes and CD34 + cells and the viability in bone marrow aspirate (BMA) were analysed with a CytoFLEX Flow Cytometer. The reorientation technique showed significantly higher cell counts than the conventional technique in all parameters. Leucocytes per nl increased from 5 ± 2 to 12 ± 4 (p < .001), and CD 34 + cells per μl increased from 40 ± 40 to 140 ± 98 (p = .003). There was no difference between anterior and posterior harvesting at the iliac crest or between use of a thick and use of a thin needle. Use of the reorientation technique, compared to employing the conventional technique, has a significant advantage since the number of leucocytes and CD34 + cells can be tripled. For the use of bone marrow aspirate in the case of arthritis, it might therefore be a future option to harvest a maximum cell yield through the new reorientation technique and to omit centrifugation. However, the clinical relevance of these findings remains the subject of future studies.Level of Evidence: Level I.Clinical relevance: Enhanced technique of BMA for knee surgeons to ensure the maximum cell yield for stem cell therapy in regenerative medicine.

Positive and negative pressure irrigation in oval root canals with apical ramifications: a computational fluid dynamics evaluation in micro-CT scanned real teeth.

To compare using computational fluid dynamics (CFD) the flow pattern, irrigant velocity, apical pressure and shear stress produced by negative (MiC) and positive pressure with different types of needles (side-vented (SV), front-vented (FV) and notched (N)) at two insertion depths in the apical ramification of oval root canals. The micro-CT of a mandibular molar with an oval root canal with an apical ramification was used for computational analysis after preparation and geometric reconstruction. Geometries with the needles in two positions (1 and 3mm from WL) were created to run the simulations. Key parameters of irrigation were displayed with CFD and compared. The penetration depth of the needle in the root canal strongly influenced shear stress and apical pressure. The three needles revealed that the highest shear stress, velocity and apical pressure were 1mm from the WL and generated medium velocities. In N simulations, the fluid flow did not reach the apical ramification and the lowest shear stress values for positive pressure needles were found. The predominant axial component for FV revealed a different pattern of irrigation with high shear stress values and higher apical pressures than those exerted by other needles. SV simulations had generalized fluid flow in most of the main canal, the highest shear stress values and lower apical pressure than the threshold determined for risk of extrusion. MiC was associated with low velocity, shear stress and apical pressure. The SV needle demonstrated a combination of low positive pressure and high shear stress; while N had the lowest shear stress and FV the highest apical pressure. MiC generated fluid flow in part of the apical ramification with negative apical pressure values but low shear stress and velocity.

The Capacity of Periodontal Gel to Occupy the Spaces Inside the Periodontal Pockets Using Computational Fluid Dynamic.

The aim of the current work is to demonstrate the capacity of a new periodontal gel to occupy the spaces inside the periodontal pockets through Computational Fluid Dynamic (CFD). The test gel consists of two resorbable medical grade polymers (PEO, Poly Ethylen Oxide and HPMC, Hydroxy Propyl Metyl Cellulose), Type I Collagen, SAP (Vitamin C), and PBS (Saline Solution), while the control gel is 14% doxyclin controlled release gel, which is used for treating periodontal pockets with probing ≥5 mm after scaling and root plaining. The study examined the fluid dynamic analysis (Computational Fluid Dynamic—CFD) of two different gels, used in dentistry to treat periodontitis, in relation to both the geometry of the periodontal pocket and the function of two different types of needles that are used to distribute the preparation. The periodontal pocket was determined by reading DICOM images taken from the patient’s CAT scan. The results show that the H42® gel comes out uniformly compared to the other gel. Moreover, it is possible to observe how the rheological properties of the gel allow the fluid to spread evenly within the periodontal pocket in relation to the geometry of the needle. In particular, H42® gel exits in a constant way both from the first and the second exit. In fact, it was observed that by changing the geometry of the needle or the type of periodontal gel, the distribution of the gel inside the pocket was no longer homogeneous. Thus, having the correct rheological properties and correct needle geometries both speeds up the gel and optimizes the pressure distribution. Currently, the literature is still lacking, therefore further studies will be needed to confirm these results.

The Feasibility and Histological Diagnostic Accuracy of Novel Menghini Needle (EUS Sonopsy CY™) for Endoscopic Ultrasound-Guided Fine-Needle Aspiration Biopsy of Solid Pancreatic Masses: A Prospective Crossover Study Comparing Standard Biopsy Needles.

Background and Objectives Recently, a 21G Menghini-type needle for EUS-guided fine-needle aspiration biopsy (EUS-FNAB) has been developed. The stylet of the EUS Sonopsy CY™ remains inside the needle during aspiration. Therefore, it is expected to obtain higher-quality histological core specimens without crushing the material or blood contamination. The aim of this study is to evaluate the feasibility and diagnostic accuracy of EUS-FNAB of solid pancreatic masses with this new biopsy needle. Methods A total of 30 patients with solid pancreatic masses who underwent EUS-FNAB with two different types of needles, EUS Sonopsy™ and ProCore™, were included in a prospective, randomized, controlled, crossover study. All the pancreatic masses were punctured with the two needles and were randomized regarding the order of the needle to be used. The primary outcome was to compare the diagnostic accuracy and the rates of tissue acquisition of the two needles. Results The tissue acquisition rate was not significantly different between the EUS Sonopsy CY™ needle and the ProCore™ needle (78.6% vs. 82.1%, P = 1.00). The histological diagnostic accuracy was also similar between the two needles (73% vs. 80%, P = .63). There was also no difference regarding the accuracy of cytology alone and the combination of both histological and cytological assessments between the EUS Sonopsy CY™ needle and the ProCore™ needle (90% vs. 87%, P = 1.00 and 90% vs. 90%, P = 1.00, respectively). Conclusions EUS Sonopsy CY™ is a reliable device for EUS-FNAB of solid pancreatic masses.

Potential of Laser Doppler Flowmetry in the Medical Needle Insertion Procedures.

Medical needle insertion procedures possess the risk of life-threatening blood vessel rapture. Here we report a compact laser Doppler Flowmetry (LDF) based system that has a potential of blood vessel detection in the vicinity of the moving needle. The developed LDF system comprises two optical fibers inserted into the needle (the probe), a laser unit and a photodetector. The latter collects the signal produced by photons, scattered from the moving red blood cells that is further converted into perfusion value. Using LDF system, we have been able to detect the flow independently from the needle penetration angle, site or depth. Moreover, we showed that the blood vessel can be identified inside the tissue phantom while the probe is moving. Our results demonstrate that the developed LDF system is flexible and compatible with different types of needles and thus has a potential in the needle insertion procedures.

Comparison of ignition, injection and micro - Explosion characteristics of RP-3/ ethanol and biodiesel / ethanol mixed drops

The ignition, injection, and micro-explosion characteristics of aviation fuel (RP-3)/ethanol mixed droplets and biodiesel/ethanol mixed droplets at different proportions under high temperature conditions (420 °C) were compared using an experimental setup. A device for measuring small droplet volumes was designed using an infusion set and different types of needles, and a corresponding equation was established. Mixed droplets suspended on high-temperature resistance nichrome wire with a diameter of 0.2 mm were heated by sending them to a position approximately 2 mm from the forklift preheating plug using a moving rail. SLR and high-speed cameras were used to observe the flame structure as well as the injection and micro-explosion of the mixed droplets during combustion, respectively. Expansion, injection, and micro-explosion were observed in the biodiesel/ethanol mixed droplet experiments when the biodiesel content was 60%. Although the micro-explosion of mixed droplets of aviation fuel/ethanol was not observed, expansion and ejection of the droplets were observed. Image Pro-plus software was used to calculate the diameters at different times in the combustion cycle of the droplets. Through this analysis, the occurrence of micro-explosion was described, and a model for the calculation of micro-explosion strength was established.

Effects of the Numbers and the Shapes of Venting Slits on Intraocular Pressure after Baerveldt Glaucoma Drainage Implant

ABSTRACTPurpose: Venting slits are widely used as an effective method to avoid the high intraocular pressure (IOP) phase immediately after the implantation of non-valved glaucoma drainage devices. However, there have been no detailed reports comparing the types of needles used and the numbers of slits made. In this study we investigated the effects of different needle types and the number of venting slits.Methods: IOP was measured using a Keyence NR-600 transducer connected to the limbus of a pig eye with a 27G needle. A microsyringe pump was also connected to the corneal limbus using a 27 G needle to make a continuous perfusion system at the rate of 200 μl/hr. The silicone tube of a Baerveldt glaucoma drainage implant (BG101-350) was ligated near the plate and then implanted in the anterior chamber of the pig eye. The tube was covered with scleral tissue of another pig eye after 1 or 3 venting slits were created in the middle of the outer diameter using different types of needles (7–0 Vicryl®, 7–0 PDSⅡ®, 5–0 PDSⅡ®, 3–0 PDS Plus®). IOP measurement was started from 50 mmHg and then we monitored the chronological changes of IOP for 15 minutes.Results: The IOPs at 15 minutes after continuous perfusion with the venting slits made using 7–0 Vicryl needles were 29.0 ± 2.5 mmHg (1 slit) and 23.1 ± 8.3 mmHg (3 slits). The IOPs were 23.1 ± 3.1 mmHg and 23.5 ± 4.7 mmHg with 7–0 PDS needles (1 slit and 3 slits, respectively), 21.8 ± 2.2 mmHg and 20.8 ± 4.3 mmHg with 5–0 PDS needles (1 slit and 3 slits, respectively), and with 3–0 PDS needles they were 12.2 ± 3.0 mmHg for one slit and 13.2 ± 3.5 mmHg for 3 slits.Conclusions: Usage of a round (PDS) needles produces more predictable IOP than a spatulated (Vicryl) needle.

Tele-Operated MRI-Guided Needle Insertion for Prostate Interventions

Prostate cancer is one of the leading causes of death in men. Prostate interventions using magnetic resonance imaging (MRI) benefits from high tissue contrast if compared to other imaging modalities. The Minimally Invasive Robotics In An MRI environment (MIRIAM) robot is an MRI-compatible system able to steer different types of needles towards a point of interest using MRI guidance. However, clinicians can be reluctant to give the robot total control of the intervention. This work integrates a haptic device in the MIRIAM system to allow input from the clinician during the insertion. A shared control architecture is achieved by letting the clinician control the insertion depth via the haptic device, while the robotic system controls the needle orientation. The clinician receives haptic feedback based on the insertion depth and tissue characteristics. Four control laws relating the motion of the master robot (haptic device) to the motion of the slave robot (MIRIAM robot) are presented and evaluated. Quantitative and qualitative results from 20 human subjects demonstrate that the squared-velocity control law is the most suitable option for our application. Additionally, a pre-operative target localization algorithm is presented in order to provide the robot with the target location. The target localization and reconstruction algorithm are validated in phantom and patient images with an average dice similarity coefficient (DSC) of 0.78. The complete system is validated through experiments by inserting a needle towards a target within the MRI scanner. Four human subjects perform the experiment achieving an average targeting error of 3.4[Formula: see text]mm.

Comparison of the Effects of using three Different Types of Needles on Sub Arachnoid Block: A Clinical Study

Comparison of the Effects of using three Different Types of Needles on Sub Arachnoid Block: A Clinical Study

Effect of ultrasound image enhancement software on the quality of vision of regional anesthesia needles.

Our objective was to evaluate and compare the visualization of different types of needles with or without ultrasound image enhancement software, both in biological tissues and artificial models. This is an observational study on fresh porcine tissue and gelatin models. Six types of plexus needles were studied. The same anesthesiologist performed in-plane punctures with each needle at 30°, 40° and 50° in both 2D mode and using software-based enhanced mode without changing position, generating 72 images. The images were evaluated blind by 38 anesthesiologists with at least two years of experience in ultrasound and rated from 0 to 10. A univariate and multivariate analysis was performed to identify differences between the images according to needle, mode, angle and experimental model. We described the results as mean (standard deviation). The Echoplex needle, 8.31 (1.94), was significantly better than the Sonoplex needle, 7.53 (2.16), P=0.0003, and both were significantly better than the other needles (P<0.0001). Significant differences were also found in favor of the gelatin model, 7.26 (2.48) vs. 6.24 (3.67), P<0.0001, and with ultrasound image enhancement software, 8.59 (1.55) vs. 4.91 (3.31), P<0.0001. These differences were confirmed by multivariate analysis. Although there are differences between the different types of needles used with ultrasound visualization strategies, ultrasound image enhancement software provides good visualization, regardless of the model chosen.

Which needle in the treatment of thyroid nodules?

Thyroid nodules are a common finding in general population, with a prevalence of 20% to 70% at ultrasound (US) examination. Many of them are benign but treatment can be necessary to relief compressive symptoms. In the last years, percutaneous ablations have achieved amazing development in the treatment of thyroid nodules as they provide a minimally invasive but effective approach. We aimed to summarize the main aspects related to treatment of thyroid nodules with radiofrequency ablation (RFA), focusing on the use of different types of needles. A narrative review was performed and all papers analyzed reported good results in terms of nodule's size reduction and symptoms relief. No major complications have been reported, even though needles of bigger size seemed related with major risks of post-procedural local edema. Thus, thinner internally cooled multi tined needles [18-19 Gauge (G)] rather than larger needles (14 G) seem to have better results and less complications.

Biocompatibility assessment of cyclic olefin copolymers: Impact of two additives on cytotoxicity, oxidative stress, inflammatory reactions, and hemocompatibility.

This work reports the biocompatibility evaluation of cyclic olefin copolymers (COC) as candidates for implantable medical devices. The focus was to establish the influence of two major additives (antioxidant and lubricant) on the overall biocompatibility. The cytotoxicity was evaluated according to ISO 10993-5 guidelines using L929 fibroblasts, HUVEC, and THP-1-derived macrophages. Oxidative stress (ROS, GSH/GSSG, and SOD analysis) and pro-inflammatory cytokines (Il-6 and TNF-α secretion) were quantified using THP-1 cells in direct contact with films. Hemocompatibility was assessed through haemolysis testing, dynamic blood coagulation, platelet adhesion, and activation (membranous P-selectin expression). Results show that the different types of COC have successfully passed the in vitro biocompatibility tests. The presence of antioxidant induces however a slight decrease in ROS production in correlation with a high SOD activity and a modification in blood coagulation profile probably linked to antioxidant recrystallization phenomenon on the surface of COC. The lubricant presence reduced haemolysis, fibrinogen adhesion, and platelet activation. Surface nanotopography of COC highlights different types of needles and globules according to the present additive. Those primary results indicate that COC are promising biomaterial. However, additives influenced some biological parameters pointing out the necessity of a global approach of risk analysis for biocompatibility evaluation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3333-3349, 2017.

Pen needle design influences ease of insertion, pain, and skin trauma in subjects with type 2 diabetes

ObjectivePen needles used for subcutaneous injections have gradually become shorter, thinner and more thin walled, and thereby less robust to patient reuse. Thus, different needle sizes, alternative tip designs and...

Calculating Curved Needles Deformation in Automated High-Dose Rate Brachytherapy Operations

The article outlines the approach to applying the mechatronic technologies and robotic systems in carrying out the brachytherapy operations. To calculate the elastic state of the flexible needles of different geometry in the prostate model, a mathematical model of the flexible needle deformation has been applied which took into account the medium reaction and was based on the theory of flexible and elastic rods. The numeric calculations for different types of needles have been introduced for the first time. Also for the first time the advantages of applying flexible needles for brachytherapy procedure have been mathematically justified.