Plastic Needle Research Articles

NiFe2O4@SiO2 superparamagnetic nanoparticles as contrast agents in image-guided adaptive brachytherapy (IGABT)

Focusing on the study of superparamagnetic iron oxide samples for applications as contrast agents, the potential utility of NiFe2O4@SiO2 sample as a contrast agent in image guided adapted brachytherapy (IGABT) treatments is described here. This magnetic sample was prepared by controlled hydrothermal synthesis with urea addition and further TEOS reaction using the Stöber method. X-ray patterns show diffraction maxima indexed to a cubic symmetry of S. G. Fd-3m with Z = 8, compatible with an inverse spinel-type structure. Polyhedral shape particles with a size of about 21 ± 5 nm, together with a homogeneous silica coating of 12.7 ± 1 nm thickness were observed in TEM images Catheters and plastic needles containing NiFe2O4@SiO2 sample in agarose solution mixture were investigated. Images obtained by magnetic resonance imaging (MRI), computed tomography (CT) and X-ray of the ovoid applicator containing NiFe2O4@SiO2 sample in agarose solution mixture, suggest that this sample may be useful for visualizing the source path by performing a T2 weighted MRI and without the need to acquire a CT image. This process reduces uncertainties due to patient movements between imaging modalities as well as procedure time. MRI and CT images of the interstitial needles filled with this solution at different concentrations confirm that it is also suitable for use as a contrast agent. Finally, the investigated sample-agarose mixture was also inserted into a block of human-like pork tissue to approximate an “in vivo” experimentation. The results suggest that the studied sample may be useful in IGABT treatments and intraoperative BT where a series of catheters are implanted into the surgical cavity. Currently, the contrast agents used are not visible inside plastic needles. Our study shows that no toxicity is introduced into the system since the sample is contained within plastic catheters and never encounters the tissue.

PHSOR11 Presentation Time: 9:50 AM: Optimizing Scanning Parameters for MR-Guided Brachytherapy: A Study on MR-Line Marker Positioning in Plastic Sharp Needles

PHSOR11 Presentation Time: 9:50 AM: Optimizing Scanning Parameters for MR-Guided Brachytherapy: A Study on MR-Line Marker Positioning in Plastic Sharp Needles

A Novel Combined Approach to Better Predict Sealing Performance of Luer Lock Connectivity.

Luer systems, for example Luer-needle hub with syringe's Luer cone tip and its Luer lock Adapter, are common interface on medical devices. One of the key questions in this application is about the safety guaranty and dose accuracy. It is then crucial to study the sealing between these elements. In this study we combine the use of Finite Element Analysis (FEA) and Multiscale Contact Mechanics (MCM) to analyze the connectivity and sealing performance of a glass syringe and a plastic needle Luer hub.This methodology has been applied before to the contact between glass and rubber and this is the first time that it is used for the contact between glass and plastic materials. The use of FEA allows to calculate the contact pressures and the nominal area of contact. The surface topographies of the two surfaces were measured, over a wide wavelength range (mm to nm). Subsequently, the air and liquid interfacial flow (leakage) is calculated using Persson's MCM theory which considers the roughness and elasto-plasticity of the interfacial surfaces. The theoretical predictions are compared to experimental leak measurements by pressure decay method. Further analysis is conducted, evidencing the key features that are responsible for a good sealing.

Life of a Type 1 diabetic.

This article discusses the life of a Type 1 diabetic. Everything is a danger. Stress, flu, infection, or a common cold could all lead to a hospital stay. There are many negative long-term effects: blindness, loss of a limb, heart attacks, etc. Every day is an effort to keep on top of things. The diabetes cannot be forgotten or ignored. The cost of living with diabetes is atrocious, between the devices, insulin, and other needed supplies. It is expensive to be sick. On top of the insulin pump, there are numerous supplies, such as reservoirs to hold the insulin, the infusion sets to put the plastic needle into the body, along with tubing to carry the insulin from the pump to the insertion point on the abdomen. There are also continuous glucose monitors (CGM), which include a transmitter, as well as sensors that have to be changed weekly. These items are much needed for people like the author, who after having diabetes for 24 years, find it difficult to feel low blood sugars. This difficulty feeling low blood sugars is quite dangerous, and may lead to seizures, brain damage, or even death if unnoticed and untreated. With CGM technology, the transmitter and sensors have saved the author on multiple occasions from seizures, or worse. They are a necessity, and the author needs the CGMs to protect her life. The author highlights a promise of hope in the Canadian Government's plan to financially cover "diabetic medications and supplies." And while it would not cover the expensive drugs not currently covered by the author's insurance, it does mean insulin and oral medications for Type 2 diabetes will no longer be paid out of pocket. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Effects of the Irrigation Needle Design on Root Canal Disinfection and Cleaning

IntroductionThis ex vivo study evaluated the disinfecting and cleaning effects of root canal preparation using sodium hypochlorite irrigation with 3 different needle designs. MethodsMesial roots from extracted mandibular molars with Vertucci class II configuration were anatomically matched based on micro-computed tomography (micro-CT) analyses and distributed into 3 groups (n = 18/group). The canals were contaminated with a mixed bacterial culture for 30 days and then subjected to preparation using 2.5% sodium hypochlorite irrigation with open-ended flat needle (3 mm short of the working length - WL), closed-ended side-vented irrigation needle (1 mm short of the WL), or a closed-ended plastic needle with 2 lateral outlets (TruNatomy) (1 mm short of the WL). Bacteriological samples were taken from the canals before (S1) and after preparation (S2). After another micro-CT scan, the roots were sectioned and samples were also taken from the apical canal segment (S3). Bacterial reduction was assessed by quantitative real-time polymerase chain reaction. The amount of accumulated hard tissue debris was evaluated by micro-CT. ResultsA substantial reduction in bacterial counts was observed in all 3 groups when comparing S1 with S2 (99.95%, 98.93%, and 98.90% in the open-ended, closed-ended, and TruNatomy needle groups, respectively) (P < .01). No significant differences were observed between groups for bacterial reduction in the full and apical canal (P > .05). There were no intergroup differences in the amount of accumulated hard tissue debris either (P > .05). The open-ended needle group showed significantly more specimens with quantitative real-time polymerase chain reaction negative results for bacteria in S3 than TruNatomy (P < .05). ConclusionWhen used up to an appropriate insertion depth, the 3 needle types result in similar antibacterial and cleaning performance, provided variables such as needle size and irrigant type, volume and flow rate are controlled. Exclusive analysis of the apical segment, including the isthmus, revealed that the open-ended needle yielded more cases negative for bacteria.

A simple technical innovation to prevent needle stick injuries among dental professionals.

Dental healthcare personnel face the potential danger of being exposed to infectious patients while administering local anesthesia injections during dental operations. This could lead to unintentional transfer of infectious diseases from patients to physicians. Although safety measures such as the One-hand-scoop technique and the use of safety syringes, plastic needle cap holders, and needles with safety caps are in place, there have been instances of needle stick injuries reported in clinics. This might be due to the lack of adherence to conventional safety measures or the impracticality of safety techniques and safety syringes. This article aims to demonstrate the utilization of dental tweezers, specifically London College tweezers or dental forceps, for the secure recapping of needles, eliminating the requirement for extra equipment or devices. After obtaining ethical approval (Approval No.: 024-01-2024) from the College of Dentistry, Dar Al Uloom University, 67 dental professionals, with consent for participation in the study, were included. They were requested to use dental tweezers/London College tweezers and dental extraction forceps such as maxillary anterior, mandibular anterior, and maxillary bayonet root forceps individually to recap the local anesthetic needles. The efficacy of these techniques was evaluated against the one-hand scoop technique for its ease, convenience, and reliability in preventing needle stick injuries. The evaluation of dental professionals regarding the ease of using dental tweezers to recap needles, compared to the one-hand scoop technique (p=0.592), maxillary bayonet root forceps (p=0.746), mandibular anterior forceps (p=0.380), and maxillary anterior forceps (p=0.808), did not yield statistically significant results. The assessment of the procedural simplicity of the one-hand scoop technique showed a satisfaction rate of over 40%, whereas the application of dental tweezers resulted in a satisfaction rate of 30%. However, the use of dental tweezers for needle recapping resulted in a satisfaction rate of over 50%, compared to a satisfaction rate of 30% for the one-handed scoop technique. There is no statistically significant difference in the assessment of the efficacy of dental tweezers and the one-hand scoop technique, bayonet root forceps, mandibular anterior forceps, maxillary anterior forceps, and dental tweezers for the needle capping technique. Therefore, dental forceps can be used instead of the one-handed scoop approach. The needle recapping procedure outlined in our study, aimed at preventing needle stick injuries, is simple to implement, and all dental specialties have convenient access to the required instruments.

Reducing apical voids for intra-canal sealer injection using a modified passive deflation needle.

The aim of the study was to evaluate the ability of a modified passive deflation needle to reduce the apical voids during the intra-canal iRoot SP sealer injection. A modified passive deflation injection needle was designed. Forty 20°-curved and twenty S-shaped single-canal resin block models were allocated into six groups. Each group was mechanically prepared to #25/04 or #25/06 file; then the root canals were injected with iRoot SP sealer using a modified needle or a normal plastic needle. Radiographs were taken to measure the length of apical void in each specimen. Similarly, twenty single-canal extracted premolars were collected and randomly divided into four groups. Each group was prepared to #25/04 or #25/06 file; then the root canals were injected with iRoot SP sealer using a modified needle or a normal plastic needle. Roots were then scanned using micro-computed tomography (micro-CT), and the volume of voids in root canals was analyzed and compared among groups. Statistical analysis demonstrated that the length and the volumetric percentage of voids were much lower in the modified needle group in both resin block root canal models and extract teeth than the normal plastic needle group (P < 0.05). The modified passive deflation needle can efficiently reduce apical voids during the intra-canal iRoot SP sealer injection.

Clinical outcomes using a 3D printed tandem-needle-template and the EMBRACE-II planning aims for image guided adaptive brachytherapy in locally advanced cervical cancer

Background Extensive local disease or narrow vagina may compromise brachytherapy (BT) in patients with cervical cancer. This is the first study to analyze long-term outcomes of using 3D printed vaginal tandem-needle templates (3DP TNT) for transvaginal insertion of needles in parallel (P) or parallel and oblique (P&O) direction to the tandem. Material and methods All patients treated with BT using 3DP TNT from 2015-2020 were included. Decision to use a 3DP TNT and preplanning were made after 4-5 weeks of external beam radiotherapy, based on gynecological examination and MRI with a tandem-ring applicator in situ. The TNT was 3D-printed in house consisting of a circular template with P&O holes for guidance of plastic needles and a shaft fitting the uterine tandem. Thus, the radioactive source was never in direct contact with the 3DP TNT. The TNT was 3D printed in a standard or personalized configuration. Planning aims were based on the Embrace II protocol. Results 101 patients (median age of 63 years) were included: 49 with P needles only and 52 with P&O needles. Personalized TNT was used in 19 patients in the P&O group. Performance status (WHO) was > 0 in 48%. FIGO2018 stage III-IV was present in 77%. T-score at diagnosis and BT was 9.1 and 6.3 respectively, with a significantly higher T-score in the P&O compared to P group. The mean high-risk CTV D90 was 93 Gy with no significant difference between the two groups. Three-year local control rates were 85%, 95%, 75% for the overall, P- and P&O group respectively and 68%, 80% and 56% for cancer specific survival. Grade ≥3 treatment related complications were observed in 10 (10%) patients. Conclusions 3DP TNT for BT in cervical cancer provides successful management of very extensive local disease and/or unfavorable anatomy with the possibility for treatment individualization.

Extending the Lifetime of Copper-beryllium Alloys as Plastic Injection High-end Needle Valve Mold Nozzle Tips Through a Heat-treatment-based Microstructure Optimization Approach

Extending the Lifetime of Copper-beryllium Alloys as Plastic Injection High-end Needle Valve Mold Nozzle Tips Through a Heat-treatment-based Microstructure Optimization Approach

Возможности создания пункционной насадки для конвексного УЗ-датчика с использованием технологии 3D-печати.

Introduction. Percutaneous surgery is one of the methods of surgical treatment of renal stones. The most difficult stage of the operation is the creation of percutaneous access to the pyelocaliceal system of the kidney. To facilitate access under ultrasound (US) guidance, it is customary to use a needle guide which is fixed to the US-probe. Taking into account the sanctions of the equipment manufacturing countries, Russian specialists may potentially find themselves in conditions of a shortage of components and particularly needle guide for ultrasound probes. In this regard, it was decided to develop the possibility of printing a needle guide for an ultrasound probe using 3Dprinting technology. Materials and methods. Using a handheld 3D laser scanner, a metal needle guide for the convex ultrasound probe was scanned, the necessary changes were made for use, and a plastic needle guide was created using 3D printing. Results. The needle, when passed into the grooves with preset angles of the printed needle guide, exactly matches the dotted aim on the monitor of the ultrasound machine, similar to the original probe. Conclusion. The use of 3D-printing in the absence of certain components, in particular, a needle guide for an ultrasound probe, allows to quickly obtain a working sample that is not inferior to the original one.

A power Doppler ultrasound method for improving intraoperative tip localization for visually obstructed needles in interstitial prostate brachytherapy.

High-dose-rate (HDR) interstitial brachytherapy (BT) is a common treatment technique for localized intermediate to high-risk prostate cancer. Transrectal ultrasound (US) imaging is typically used for guiding needle insertion, including localization of the needle tip which is critical for treatment planning. However, image artifacts can limit needle tip visibility in standard brightness (B)-mode US, potentially leading to dose delivery that deviates from the planned dose. To improve intraoperative tip visualization in visually obstructed needles, we propose a power Doppler (PD) US method which utilizes a novel wireless mechanical oscillator, validated in phantom experiments and clinical HDR-BT cases as part of a feasibility clinical trial. Our wireless oscillator contains a DC motor housed in a 3D printed case and is powered by rechargeable battery allowing the device to be operated by one person with no additional equipment required in the operating room. The oscillator end-piece features a cylindrical shape designed for BT applications to fit on top of the commonly used cylindrical needle mandrins. Phantom validation was completed using tissue-equivalent agar phantoms with the clinical US system and both plastic and metal needles. Our PD method was tested using a needle implant pattern matching a standard HDR-BT procedure as well as an implant pattern designed to maximize needle shadowing artifacts. Needle tip localization accuracy was assessed using the clinical method based on ideal reference needles as well as a comparison to computed tomography (CT) as a gold standard. Clinical validation was completed in five patients who underwent standard HDR-BT as part of a feasibility clinical trial. Needle tips positions were identified using B-mode US and PD US with perturbation from our wireless oscillator. Absolute mean±standard deviation tip error for B-mode alone, PD alone, and B-mode combined with PD was respectively: 0.3±0.3mm, 0.6±0.5mm, and 0.4±0.2mm for the mock HDR-BT needle implant; 0.8±1.7mm, 0.4±0.6mm, and 0.3±0.5mm for the explicit shadowing implant with plastic needles; and 0.5±0.2mm, 0.5±0.3mm, and 0.6±0.2mm for the explicit shadowing implant with metal needles. The total mean absolute tip error for all five patients in the feasibility clinical trial was 0.9±0.7mm using B-mode US alone and 0.8±0.5mm when including PD US, with increased benefit observed for needles classified as visually obstructed. Our proposed PD needle tip localization method is easy to implement and requires no modifications or additions to the standard clinical equipment or workflow. We have demonstrated decreased tip localization error and variation for visually obstructed needles in both phantom and clinical cases, including providing the ability to visualize needles previously not visible using B-mode US alone. This method has the potential to improve needle visualization in challenging cases without burdening the clinical workflow, potentially improving treatment accuracy in HDR-BT and more broadly in any minimally invasive needle-based procedure.

PO16: Commissioning of the Varian Universal Interstitial Cylinder (UIC) System for HDR Brachytherapy of Cervical Cancer

<h3>Purpose</h3> Varian Medical Systems (VMS) has recently released the Universal Interstitial Cylinder (UIC) for use with Ir-192 HDR brachytherapy. We commissioned one cylinder with a plastic Universal Cervix Probe (UPC) and plastic interstitial needles using CT and MR images. A phantom specifically designed to avoid the introduction of water or water-like materials into the needle guide tracks was used and various marker strands were investigated to accurately reconstruct source positions. <h3>Materials and Methods</h3> CT and MR scan were taken for the UIC set: one cylinder (30 mm diameter) with plastic UCP (80 mm, 30 degrees) and eight interstitial needles (channel #2-#9). To compare three different methods for channel identification, CT images (Siemens Biograph mCT, Siemens AG) with slice thickness of 0.6 mm were taken with either no radio opaque markers, VMS-numbered markers, or nylon coated stainless steel leader wires ("fish wire") which aid in channel identification and image registration. The MR images were taken on a 3T Magnetom Skyra Siemens MRI scanner using 3D T1 and 2D T2 weighted clinical HDR gynecological MRI protocols. An HDR MRI Lumen Marker (C4 Imaging, LLC) was placed in the channel #9 to check for any applicator rotation. The needle guide track openings at the distal end of the UIC cylinder causes liquid to be introduced into the tracks which results in unintended MR and CT signal. A gynecological phantom was constructed by placing the applicator set into three different phantom materials: wet towels, gelatin, or ground beef. Image quality of the CT and MRI scans for these phantoms were compared for treatment planning. The applicator dimensions were verified on CT and kV planar images. Dimensions from the vendor solid applicator models, which are based on the computer-aided design model files of the specific applicator were compared to those on CT and kV images. <h3>Results</h3> The phantoms made of wet towels or gelatin allowed significant amounts of liquid to enter the needle guide tracks from the holes in the distal end of the cylinder. This can mislead as to the actual source positions in the applicator. Specifically, it resulted in channels with unintended MR and CT signal (Figure 1a). The ground beef phantom was developed to limit this introduction of liquid into the cylinder (Figure 1b). CT scans with no markers displayed substantially wider needle guide tracks than the plastic needles (Figure 1b). CT scans with VMS-markers showed significant artifact (Figure 1c). CT scans with fish wire provided the best visibility of the needles within the needle guide tracks (Figure 1d). This scan along with the solid applicator model was also used to confirm distance from the outer wall to the inside of the needle guide track (8 mm) and to the center of the needle (7 mm) and the 30 mm diameter of the cylinder (Figure 1d). The use of an MR marker allowed that needle (channel #9) to be identified in the T1w MR scan (Figure 1b). The dimensions of the applicators could be validated on CT (Figure 1d) and kV planar images (Figure 1e). <h3>Conclusions</h3> The UIC applicator was commissioned for CT and MR image based treatment planning for HDR brachytherapy. Planar kV images verified dimensions of applicator against vendor specs. Accurate source position reconstruction was feasible using CT scan with 0.6 mm slice thickness and radio-opaque markers. The use of a ground beef phantom rather than a liquid based phantom minimized unintended MR and CT signal by limiting introduction of fluid into the needle guide tracks.

GSOR9 Presentation Time: 9:40 AM: 3D-Printed Ovoids with Rotational Needle Guides for Patient-Specific Hybrid Applicator Gynecologic Brachytherapy

<h3>Purpose</h3> To develop ovoid caps having a rotational guide to assist in needle insertion to predetermined locations for preferential dose deposition. <h3>Method</h3> The custom ovoids were designed to be compatible with a titanium FSD tandem and ovoid applicator set and plastic needles (Varian, Palo Alto, CA). The rotational needle guides are designed in three parts as illustrated in Figure 1. For each ovoid, there are three needle guides on both sides of the colpostat tandems: anterior, middle, and posterior pairs. The anterior and middle needle guides are designed perpendicular to the colpostat tandem while the posterior needle guides are angled 30-degrees posteriorly. The opening for the colpostat tandem is contained within the anterior section. The posterior section of the ovoid is attached to the anterior section with a titanium screw. The middle ring is free to rotate at predetermined angles in a plane perpendicular to the tandem direction. Titanium set screws fix each component to the colpostat tandems. The custom ovoid design is fabricated with a FormLabs Form 3B 3D printer (FormLabs, Somerville, MA) using a USP (U.S. Pharmacopeia) Class VI biocompatible certified Bio-Clear resin. Printed ovoid caps are sterilized for use using a 121-degree Celsius Gravity cycle for 30 minutes. The original stainless-steel mandrins used to stiffen the needles during implantation were replaced with 16 gauges wire to provide sufficient insertion support while providing more flexibility in negotiating the needle guide angles. <h3>Result</h3> The 3D-printed ovoids were used for a patient presenting with stage IIB cervical cancer receiving 2750 cGy in five fractions of brachytherapy. Two needles were placed within the medial posterior and medial middle guides of the patient right ovoid. The middle guide was rotated 10 degrees towards the patient right (Figure 2B). The acrylic-based 3D-printed resin material has HU values closer to surrounding tissues compared to the high-density polyethylene ovoids of the standard T&O set. <h3>Discussion</h3> Hybrid gynecologic applicators are beneficial in achieving dose distributions beyond the traditional "pear-shape" but can still be limited by the applicator design. Rotational needle guides within the ovoids provides added freedom in designing a patient-specific implant to reduce dose to adjacent organs at risk.

PO41 Presentation Time: 4:45 PM: Initial Experience with the New Commercial Aarhus MR Compatible Hybrid Interstitial Brachytherapy Applicator in Indian Setting

<h3>Purpose -</h3> We have been using CT based intracavitary applicator in our clinic for cervical cancer. The advent of new hybrid applicator and short sequence cube MRI sequence opened up opportunity to do advanced MRI based brachytherapy in our clinic. We present the initial clinical experience of Aarhus ring and tandem MR compatible hybrid interstitial applicator with both straight and oblique needles and no ring channel (Varian may need to add TM) which was recently approved for use in a patient with bulky cervical cancer. <h3>Material and methods -</h3> A 45 years old lady, with initial diagnosis of carcinoma cervix, stage 1B3, completed External beam radiotherapy to a total dose of 45Gy in 25 Fractions, with a good clinical response, was taken up for further treatment with brachytherapy to a total dose of 28 Gy in 4 fractions. Brachytherapy was split into two applications one week apart and two treatment fractions delivered with each application, with 8 hours gap between each fraction.We used 60 degree Aarhus applicator set with Intrauterine tandem of 40 mm length and outer ring diameter of 32 mm. The Ring includes 19 guide holes for plastic interstitial needles arranged in 2 circles, 9 in inner circle for oblique needles and 10 in outer circle for straight needles.After external radiation patient underwent MRI pelvis with only T2 weighted axial and Cube sequences, which showed residual disease limited to cervix on the right side. The depth of needle insertion into the cervix was measured on MRI to be 3cms. Procedure performed under short general anaesthesia and 4 straight plastic needles through the ring were inserted with two on either side along with 4 cm central Tandem. CT and MR performed for both applications and fused. GTV-primary and HR CTV delineated on MRI, while OARs were delineated on CT. A dose of 7 Gy per fraction prescribed to HR CTV. An optimised plan was generated on eclipse treatment planning system with repeat CT planning for remaining fractions. <h3>Results -</h3> Treatment delivery went uneventful with very minimal blood loss. Average Dose per fraction received by 90 % of volume (D90) of HR CTV was 7.617 Gy and D98 of GTV primary was 10.35 Gy, delivering a total EQD2 of 89 Gy to HR CTV and at the same time delivering 115 Gy to the GTVp. OAR doses were well constrained with Bladder 2cc receiving 79.25 Gy, Rectum 2cc constrained to 53.48 Gy, sigmoid 2cc to 58.99 Gy and small bowel to 51.98 Gy. <h3>Conclusions -</h3> We successfully implemented MRI based planning with new Aarhus applicator in our clinic. Procedure was uneventful with excellent dosimetry. We will continue to use it in our clinic for patients with locally advanced cancer.

PHSPP05 Presentation Time: 3:10 PM: Optimization Strategies in MR-Only Workflow for Interstitial and Intracavitary Gynecological HDR Brachytherapy

<h3>Purpose</h3> Image-guided interstitial and intracavitary gynecological brachytherapy (IGBT) is advancing towards MR-only workflows because of MR's superior soft-tissue contrast for tumor delineation and tissue segmentation. However, current treatment planning still necessitates the use of CT/MR fusion to aid in needle reconstruction and quality assurance (QA). In this work, we present strategies to visualize needles on MR and provide QA procedures for MR-only IGBT with comparisons to the conventional CT/MR approach. <h3>Materials and Methods</h3> Three 6F interstitial plastic needles and one CT/MR-compatible intrauterine tandem and ring (T&R) applicator set were examined in this study with the Flexitron afterloading system (Elekta Brachytherapy, Netherlands). To visualize the needles, they were immersed in demineralized water and scanned without markers in a 3T MRI system (Signa Premier; GE Healthcare, Milwaukee, WI). MR images were acquired with three protocols: 3D T1W (TR\TE 552\10 ms, and 1 mm voxel), 3D T2W (TR\TE 3051\104 ms, and 1 mm voxel) and silent Zero TE sequence (TR\TE 1060\20 ms, and 0.58 mm voxel). For QA, a 2D MR protocol (T1W, 7-10 mm thick slice) was utilized that allowed a projection-like image of an EBT3-film-based setup which was also imaged (with CT/x-ray markers) in CT (Philips, Netherlands) and x-ray imager (Varian Medical Systems, Palo Alto, CA). This setup consists of attaching catheters and four vitamin-D pills to EBT3 film pieces. The four corners of each film piece (5" x 4") were marked with skin markers that are visible in CT and MR images. These skin markers served as surrogates for a 4-point registration system between all images, and the vitamin-D pills were used to assess registration quality. An efficient film handling/scanning protocol was designed for this work and the source first dwell position (FDP) on the film was determined using a commissioned source localization algorithm. The FDP was compared between film, x-ray/CT markers, and applicator library models. <h3>Results</h3> For needle visualization, ZTE images generated a positive contrast for the interstitial needles as compared to conventional T1 and T2 images (See Figure). For QA, the 2D MR slice and x-ray image clearly displayed applicators, needles, vitamin-D pills, and skin markers allowing accurate registration to film images, visualization, and localization of the catheters, source positions, and markers in one fused image (See Figure). The tandem tip from MR was 1.1 mm longer than that of the x-ray and model which was not evident in the vitamin-D matching, implying a potential MR artifact at the tip (Sub-Figure B) which should be taken into account while planning. FDP reconstruction errors from the needle tip in MR with respect to film and x-ray markers were less than 1 mm (Sub-Figure D). <h3>Conclusions</h3> While further investigation is required, ZTE imaging offers a promising alternative to CT imaging for needle reconstruction supporting MR-only gynecological brachytherapy treatment planning. However, MR-only workflow requires special considerations in QA to account for possible systematic shifts that could exceed the level of accuracy achieved in x-ray-based IGBT.

Finding the tiny plastic needle in the haystack: how field flow fractionation can help to analyze nanoplastics in food.

While the exact health risks associated with nanoplastics are currently the focus of intense research, there is no doubt that humans are exposed to nanoplastics and that food could be a major source of exposure. Nanoplastics are released from plastic materials and articles used during food production, processing, storage, preparation, and serving. They are also likely to enter the food chain via contaminated water, air, and soil. However, very limited exposure data for risk assessment exists so far due to the lack of suitable analytical methods. Nanoplastic detection in food poses a great analytical challenge due to the complexity of plastics and food matrices as well as the small size and expectedly low concentration of the plastic particles. Multidetector field flow fractionation has emerged as a valuable analytical technique for nanoparticle separation over the last decades, and the first studies using the technique for analyzing nanoplastics in complex matrices are emerging. In combination with online detectors and offline analysis, multidetector field flow fractionation is a powerful platform for advanced characterization of nanoplastics in food by reducing sample complexity, which otherwise hampers the full potential of most analytical techniques. The focus of this article is to present the current state of the art of multidetector field flow fractionation for nanoplastic analysis and to discuss future trends and needs aiming at the analysis of nanoplastics in food.

Stop posterior wall puncture of the arteriovenous graft (AVG). New findings of cannulation techniques from a prospective observational study with an AVG model and plastic cannula for dialysis.

Posterior wall puncture of the AVG causes serious vascular access complications, but there is no concrete technical recommendation for AVG cannulation with plastic cannula. The purpose of this study is to identify cannulation techniques to reduce posterior wall puncture of the AVG using plastic cannula. Sixty-three hemodialysis nurses' cannulations on experimental models were recorded and included in this study. Cannulations were conducted on AVG and AVF models with a plastic cannulation needle. We analyzed the angle of the needle, the motion of the needle, and the location of the needle in the graft lumen. The occurrence of posterior wall puncture of the AVG model was 22.2%. The cannulation angles in the AVG model were greater than those in the AVF model (p < 0.05). In the posterior wall puncture group of the AVG model, after the tip of the needle had reached into the graft lumen, the angle of the needle was not flattened (p < 0.05) and the outer sleeve of the needle was not inserted into the graft (p < 0.05). Furthermore, posterior wall puncture of the AVG model were observed in the group with less than 5 years of dialysis nursing experience (p < 0.05). From this study, after the tip of the needle had reached into the graft lumen, flattening the angle of the needle and inserting the outer sleeve of the needle into the graft were suggested as specific cannulation techniques to reduce posterior wall puncture of the AVG. Furthermore, this study also suggests the importance of cannulation technique education for new dialysis nurses to reduce cannulation-caused complications.

Implementation of a real-time, ultrasound-guided prostate HDR brachytherapy program.

This work presents a comprehensive commissioning and workflow development process of a real‐time, ultrasound (US) image‐guided treatment planning system (TPS), a stepper and a US unit. To adequately benchmark the system, commissioning tasks were separated into (1) US imaging, (2) stepper mechanical, and (3) treatment planning aspects. Quality assurance US imaging measurements were performed following the AAPM TG‐128 and GEC‐ESTRO recommendations and consisted of benchmarking the spatial resolution, accuracy, and low‐contrast detectability. Mechanical tests were first used to benchmark the electronic encoders within the stepper and were later expanded to evaluate the needle free length calculation accuracy. Needle reconstruction accuracy was rigorously evaluated at the treatment planning level. The calibration length of each probe was redundantly checked between the calculated and measured needle free length, which was found to be within 1 mm for a variety of scenarios. Needle placement relative to a reference fiducial and coincidence of imaging coordinate origins were verified to within 1 mm in both sagittal and transverse imaging planes. The source strength was also calibrated within the interstitial needle and was found to be 1.14% lower than when measured in a plastic needle. Dose calculations in the TPS and secondary dose calculation software were benchmarked against manual TG‐43 calculations. Calculations among the three calculation methods agreed within 1% for all calculated points. Source positioning and dummy coincidence was tested following the recommendations of the TG‐40 report. Finally, the development of the clinical workflow, checklists, and planning objectives are discussed and included within this report. The commissioning of real‐time, US‐guided HDR prostate systems requires careful consideration among several facets including the image quality, dosimetric, and mechanical accuracy. The TPS relies on each of these components to develop and administer a treatment plan, and as such, should be carefully examined.

PO38: Commissioning and Workflow Development for a Real-Time, Ultrasound-Guided Prostate HDR Brachytherapy Program

Purpose: This work presents the commissioning of a real-time, ultrasound (US)-guided HDR brachytherapy system (Elekta AB, Inc.), including the hardware, US imaging system, treatment planning system (TPS) (Oncentra Prostate), and the developed workflow.Materials and Methods: Commissioning tasks were separated into (1) US imaging, (2) stepper mechanicals, and (3) treatment planning aspects. Quality assurance US imaging measurements consisted of benchmarking the spatial resolution, accuracy, and low-contrast detectability. Mechanical tests were first performed to validate the electronic encoders used within the stepper and were later expanded to evaluate the needle free length calculation accuracy. Several system-integrated measurements were performed to verify needle positioning accuracy and imaging origin coincidence measurements using the needle free length measurement as a surrogate marker, as this remains one of the largest potential sources of error. The workflow was developed through a multi-disciplinary team, including physicians, radiation-therapists, nurses, physicists, administration staff, sterilization and anesthesia staff and included multi-dry-runs of the full procedure. A detailed description of each party's role was also developed, including checklists for the planning physicist, a secondary check physicist, and a radiation therapist.Results: Needle placement accuracy was verified to within 1 mm for both sagittal and transverse imaging planes. Needle reconstruction accuracy was also rigorously evaluated. The source strength was also calibrated with the interstitial needle and was found to be 1.14% lower than when measured in a plastic needle. The calibration length of each probe was redundantly check between the calculated and measured needle free length, which was found to be within 1 mm for a variety of scenarios. Dose calculations in the TPS and secondary dose calculation software were benchmarked against manual TG-43 calculations, which were within 1% for all calculated points. Source positioning and dummy coincidence was also verified. The US-guided HDR prostate procedure consisted of six primary components: (1) the delineation of personnel and their roles, (2) HDR suite preparation prior to the treatment day, (3) day of treatment preparations, (4) patient setup, (4) pre-needle insertion plan, (5) initial insertion and live reconstruction, and (6) final imaging and planning. A set of plan evaluation metrics were established based on the currently available guidelines (ABS, ESTRO, and RTOG) and the culmination of clinical experiences across multiple institutions.Conclusions: The commissioning of real-time, US-guided HDR prostate systems requires careful consideration among several facets including the image quality, dosimetric and mechanical accuracy. The TPS relies on each of these components to develop and administer a treatment plan, and as such, should be carefully examined.

Looking back on our vaccination history

More than 65 million intramuscular injections of three approved COVID-19 vaccines have been given in the UK. Each of these injections will have used disposable plastic syringes and needles to dilute the vaccines and inject them into patients. A huge achievement, but where did all this start? Syringes have been used since the time of […]