Magnetic Seeds Research Articles

Advantages of preoperative localization and surgical resection of metastatic axillary lymph nodes using magnetic seeds after neoadjuvant chemotherapy in breast cancer

PurposeTo assess the safety and effectiveness of magnetic seeds in preoperative localization and surgical dissection of metastatic axillary lymph nodes (LN+) in breast cancer patients with axillary involvement, after neoadjuvant chemotherapy (NAC). In addition, to assess the impact of targeted axillary dissection (TAD) in reducing the rate of false negatives (FN) in sentinel lymph node biopsy (SLNB). Materials and MethodsA cross-sectional prospective cohort study was conducted from April 2017 to September 2019, including breast cancer patients with axillary lymph node involvement treated with NAC. Prior to NAC, the LN+ were marked by ultrasound-guided clip insertion. After NAC, a magnetic seed (Magseed®) was inserted in the clip-marked lymph node (MLN). During surgery, the MLN was located and removed with the aid of a magnetic detection probe (Sentimag®) and the sentinel lymph node was removed. Axillary lymph node dissection (ALND) was used to determine the rate of FN for SLNB alone and the combination of SLNB and MLN dissection, called TAD. ResultsThe study included 29 patients (mean age, 55; range, 30–78 years). Selective preoperative localization and surgical dissection were successful for all 30 MLNs (100%). The MLN corresponded to the SLN in 50% of cases. After ALND, there were 21.4% (3/14) FN with SLNB alone and 5.9% (1/17) with TAD. ConclusionsFollowing NAC, selective surgical removal of MLN by preoperative localization using magnetic seeds is a safe and effective procedure with a success rate of 100%. Adding TAD reduces the rate of FN associated with SLNB alone.

ASO Author Reflections: Magnetic Seed Localization and Tracers Add Value to Multidisciplinary Breast Programs.

ASO Author Reflections: Magnetic Seed Localization and Tracers Add Value to Multidisciplinary Breast Programs.

Hospital System Adoption of Magnetic Seeds for Wireless Breast and Lymph Node Localization.

As an alternative to traditional wire localization, an inducible magnetic seed system can be used to identify and remove nonpalpable breast lesions and axillary lymph nodes intraoperatively. We report the largest single-institution experience of magnetic seed placement for operative localization to date, including feasibility and short-term outcomes. Patients who underwent placement of a magnetic seed in the breast or lymph node were identified from July 2017 to March 2019. Imaging findings, core needle biopsy, surgical pathology results, and type of surgery were collected. Outcomes included procedural complications, magnetic seed and biopsy clip retrieval rates, and need for additional surgery. A total of 842 magnetic seeds were placed by nine radiologists in 673 patients and retrieved by six surgeons at six operative locations. The majority of breast lesions were malignant (395/659, 59.9%); 136 seeds were placed for lymph node localization. The overall magnetic seed retrieval rate was 98.6%, whereas the biopsy clip retrieval rate was 90.9%. Only six patients (0.7%) experienced a complication from magnetic seed placement. Reexcision was performed in 15.2% of patients with breast cancer; 9.6% of benign/high risk lesions were upgraded to malignancy at surgical excision. The magnetic seed technique is safe, effective, and accurate for localization of breast lesions and lymph nodes, and importantly uncouples surgery from the localization procedure. The high magnetic seed retrieval rate and low reexcision rate may reflect the accuracy of magnetic marker placement as a "second chance" localization procedure, especially in cases with biopsy clip migration.

Magnetic Seed (Magseed) Localisation in Breast Cancer Surgery: A Multicentre Clinical Trial

Introduction: The aim of this study was to evaluate the accuracy and reliability of the Magseed magnetic marker in breast cancer surgery. Methods: Thirty-nine patients with 41 implanted Magseeds undergoing surgical treatment in 3 surgical oncology departments were included in the retrospective trial to study pilot use of the Magseed magnetic marker in the Czech Republic for localisation of breast tumours or pathological axillary nodes in breast cancer patients. Results: Thirty-four breast cancer and 7 pathological lymph node localisations were performed by Magseed implantation. No placement failures, or perioperative detection failures of Magseeds were observed (0/41, 0.0%), but one case of Magseed migration was present (1/41, 2.4%). All magnetic seeds were successfully retrieved (41/41, 100.0%). Negative margins were achieved in 29 of 34 (85.3%) breast tumour localisations by Magseed. Conclusion: Magseed is a reliable marker for breast tumour and pathological axillary node localisation in breast cancer patients. Magseed is comparable to conventional localisation methods in terms of oncosurgical radicality and safety.

Photon mass limits driven by axions, Lorentz violation, chiral and gravitational anomalies in non-Riemannian spaces, and helical dynamo seeds

In this paper two types of applications of Cartan torsion to cosmology and quantum field theory are given. The first is given by massive photon axial torsion mixing through non-minimal coupling. It is shown that chiral anomalies induce upper limits on the photon mass and galactic dynamo seeds. In this example we obtain magnetic field seeds of the order of 10−16 G from a strong chiral battery magnetic field of the order of 1030 G. This cosmic magnetic field is in accordance with previous magnetic dynamo seed limits as 10−22 G ≤ Bseed ≤ 10−12 G given by Barrow et al. (Phys. Rev. D, 86, 023533 (2012). doi: 10.1103/PhysRevD.86.023533 ). In this example, as in the Prokopec et al. (Phys. Rev. Lett. 89, 101301 (2002). doi: 10.1103/PhysRevLett.89.101301 ) torsionless case, which associates Dolgov anomalies to photon mass limits, we show that at early universe scales, 10−32 eV is a very stringent limit. Here we can show that the parameter [Formula: see text], which is well within the lower bound of r needed for the magnetic field to seed galactic dynamos. Helical magnetic fields are obtained. One can also derive massive photon limits from axial chiral anomalies with torsion degrees of freedom (Duncan et al. Nucl. Phys. B, 387, 215 (1992). doi: 10.1016/0550-3213(92)90052-D ) leading to photon mass of the order of 10−11 eV. Dynamo equations are obtained from anomalous Maxwell equations as well as magnetic wave equations with photon mass, which are analytically solved. In the second example one shows that Chern–Simons (CS) current is affected by the presence of minimal coupled torsion. In this case as well one obtains a photon mass limit of the order 10−18 eV. Gravitational anomalies in Riemann–Cartan spacetime with axial torsion are also obtained. Recently, Terrano et al. (Phys. Rev. Lett. 122, 231301 (2019). doi: 10.1103/PhysRevLett.122.231301 ) computed dark matter mass constraints of the order of 10−23 eV from spin-polarised torsion balances, which has given some support for torsion theories of Einstein–Cartan type. Here, however, we deal with torsion with dynamical degrees of freedom. Lorentz violation in non-Riemannian CS currents are investigated.

Plasmonic Metallic Heteromeric Nanostructures.

Binary, ternary, and other high-order plasmonic heteromers possess remarkable physical and chemical properties, enabling them to be used in numerous applications. The seed-mediated approach is one of the most promising and versatile routes to produce plasmonic heteromers. Selective growth of one or multiple domains on desired sites of noble metal, semiconductor, or magnetic seeds would form desired heteromeric nanostructures with multiple functionalities and synergistic effects. In this work, the challenges for the synthetic approaches are discussed with respect to tuning the thermodynamics, as well as the kinetic properties (e.g., pH, temperature, injection rate, among others). Then, plasmonic heteromers with their structure advantages displaying unique activities compared to other hybrid nanostructures (e.g., core-shell, alloy) are highlighted. Some of the main most recent applications of plasmonic heteromers are also presented. Finally, perspectives for further exploitation of plasmonic heteromers are demonstrated. The goal of this work is to provide the current know-how on the synthesis routes of plasmonic heteromers in a summarized manner, so as to achieve a better understanding of the resulting properties and to gain an improved control of their performances and extend their breadth of applications.

Magnetic Fiducial Seeds for Tumor Localization in Video-Assisted Thoracoscopic Surgery (VATS): A Phantom and Ex Vivo Feasibility Study

Objective: In this study, we presented a method utilizing magnetic fiducial seeds and a magnetometer probe to help localize the non-palpable nodule prior to the final resection step in video-assisted thoracoscopy surgery. Methods: The magnetic fiducial seeds were built through tiny magnet with a diameter of 2 mm and a height of 1.5 mm. The magnetometer probe was used to detect the position of the magnetic seeds based on the distribution of the magnetic field strength. Two tests were conducted to evaluate the performance of the presented method. Results: In the phantom tests, results show that the average angular error, radial error, and probe tip to target distance error were 2.98 degrees, 2.96 mm, and 5.76 mm, respectively. In the case study with animal cadaver, the small fiducial seeds were inserted into the target lung of the pig cadaver under CT guidance prior to thoracoscopic surgery, and a 2.8-degree difference in the trajectories of the probe and the seed was measured and a 2.7 mm radial error was obtained between the nodule and the needle trajectory suggested by the probe. The probe tip to target distance was 9.7 mm in this case study. Conclusion:The study has shown that the presented method is an easy and convenient method to localize the target non-palpable nodule during video-assisted thoracoscopic surgery without a great impact on current clinical workflow. Significance: The VATS procedure could benefit from our proposed method.

Update on Management of Non-Palpable Breast Lesion

Halstedian radical mastectomy is practiced over 40 years as surgical treatment of breast cancer. For the last twenty years, breast conserving surgery (BCS) has been more practiced in the treatment of breast cancer as it provides oncological safety as well as cosmesis. Non palpable breast lesions are being increasingly diagnosed in the recent years as a result of introduction of breast cancer screening, high quality digital mammography and increase in public awareness. Accurate localisation of small, nonpalpable breast lesions is mandatory for accurate surgical management. The purpose of this article is to review the techniques systematically those have been used to locate non-palpable breast lesions which could easily be introduced in Bangladesh. Breast conserving surgery means complete removal of the tumour with a concentric margin of surrounding healthy tissue with maintenance of acceptable cosmesis. It should be followed by radiation therapy (RT) to achieve an acceptably low rate of local recurrence. Breast conserving surgery with radiotherapy has same survival benefit as mastectomy. BCS plus RT provided better outcome than mastectomy for early breast cancer and should be offered as a preferred treatment option. Experience, logistical support, and multidisciplinary approach is key to success. Radiological support with ultrasound or stereotactic localization with wires and /or ultrasound skin marking are key to have accurate wide local excision of non palpable lesions which is gold standard. Other newer techniques such as radio guided occult lesion localisation (ROLL), magnetic seeds, radiofrequency seeds localisation are a feasible and safe method of breast lesion localization as well and gaining popularity slowly. Faridpur Med. Coll. J. Jul 2019;14(2): 93-99

Comprehensive reutilization of iron in iron ore tailings: preparation and characterization of magnetic flocculants.

A large number of iron ore tailings (IOTs) are produced in steel industry, posing threat to the environment during its storage and disposal. To effectively reutilize Fe in IOTs, we propose a comprehensive utilization scheme: (1) most Fe in IOTs is extracted by concentrated hydrochloric acid to form FeCl3 flocculants; (2) after separation from the FeCl3 flocculants, a small amount of Fe is absorbed on the residue solids, which is further washed out to synthesize micron Fe3O4 as magnetic seeds. Results show that the as-synthetic FeCl3 flocculants meet the product standard for FeCl3 flocculants in China (GB/T 4482-2018) after a series of treatments including rotary evaporation, neutralization, and dilution and have comparable performance with commercial polyaluminum chloride (PAC) and polyaluminum ferric chloride (PAFC). Moreover, the addition of synthetic superparamagnetic Fe3O4 (as magnetic seeds) doubled the flocculation rate compared with as-synthetic FeCl3 flocculants alone. Finally, the reutilization of Fe in IOTs can create a direct economic value of ¥ 1.27/kg IOTs, and produce 745 g high-silicon residues for further reutilization, which indicates that our comprehensive utilization scheme is of great application potential.

Early budget impact analysis on magnetic seed localization for non-palpable breast cancer surgery.

IntroductionCurrent localization techniques used in breast conserving surgery for non-palpable tumors show several disadvantages. Magnetic Seed Localization (MSL) is an innovative localization technique aiming to overcome these disadvantages. This study evaluated the expected budget impact of adopting MSL compared to standard of care.MethodsStandard of care with Wire-Guided Localization (WGL) and Radioactive Seed Localization (RSL) use was compared with a future situation gradually adopting MSL next to RSL or WGL from a Dutch national perspective over 5 years (2017–2022). The intervention costs for WGL, RSL and MSL and the implementation costs for RSL and MSL were evaluated using activity-based costing in eight Dutch hospitals. Based on available list prices the price of the magnetic seed was ranged €100-€500.ResultsThe intervention costs for WGL, RSL and MSL were respectively: €2,617, €2,834 and €2,662 per patient and implementation costs were €2,974 and €26,826 for MSL and RSL respectively. For standard of care the budget impact increased from €14.7m to €16.9m. Inclusion of MSL with a seed price of €100 showed a budget impact of €16.7m. Above a price of €178 the budget impact increased for adoption of MSL, rising to €17.6m when priced at €500.ConclusionMSL could be a cost-efficient localization technique in resecting non-palpable tumors in the Netherlands. The online calculation model can inform adoption decisions internationally. When determining retail price of the magnetic seed, cost-effectiveness should be considered.

Primordial magnetogenesis in a bouncing universe

We investigate primordial magnetogenesis and the evolution of the electromagnetic field through a quantum bounce, in a model that starts in the far past from a contracting phase where only dust is present and the electromagnetic field is in the adiabatic quantum vacuum state. By including a coupling between curvature and electromagnetism of the form $RF_{\mu \nu}F^{\mu \nu}$, we find acceptable magnetic field seeds within the current observational constraints at 1 mega-parsec (Mpc), and that the magnetic power spectrum evolves as a power-law with spectral index $n_B=6$. It is also shown that the electromagnetic backreaction is not an issue in the model under scrutiny.

Effect of Magnetic Field and Moringa Seed Powder on Wastewater Treatment

This study was conducted to determine the effect of magnetic field (MF) and moringa seed powder (MSP) on wastewater treatment. Wastewater causes environmental and river pollution that are harmful to aquatic animals and toxic to man. Domestic wastewater was collected from the bathroom, University of Ilorin male hostel (Compound G). The wastewater was divided into four portions. First portion was allowed to flow through MF (100 mT) for 40, 60 and 80s. Second portion, 4 litres of the wastewater was poured into 5 litres capacity containers and 100, 150 and 200 mg/L of MSP was added to each container with 2 replicates. Third portion, 100, 150 and 200 mg/L of MSP was added to the wastewater after the wastewater was passed through MF for 40, 60 and 80 s and the fourth portion was the control experiment. Physical, chemical and bacteriological properties of the wastewater were determined after 2 hours. The range of reduction in turbidity for MSP, MF, combination of MSP and MF compared with the control experiment were 3.08-18.46, 9.00-23.08 and 20.03-23.08%, respectively. Reductions of total coliform were 84.21-88.42%, 36.84-47.37% and 75.26-87.89%. The range in reduction ammonia nitrate for MSP, MF, combination of MSP and MF compared with control experiment were 2.96-9.63, 0.00-1.48 and 6.67-8.89%. The values of BOD were 0.82-7.14, 0.82-2.45 and 2.24-8.37%. The results indicated that combination of MF and MSP reduced physicochemical and bacteriological properties of the wastewater. Combination of MSP and MF is recommended for treating wastewater before discharging into rivers.
 Keywords: wastewater, wastewater treatment, moringa, magnetized wastewater, water pollution

How to Safely Perform Magnetic Resonance Imaging-guided Radioactive Seed Localizations in the Breast.

When a breast lesion is seen on only magnetic resonance imaging (MRI) and needs to be excised, pre-operative MRI-guided radioactive seed localization (RSL) is preferred. However, MRI safety and radiation safety issues associated with the inability to recover a potentially lost seed in the MRI scanner room (Zone IV) have precluded this in the past. This manuscript provides a protocol for MRI-guided RSLs that meets MRI safety and radiation safety criteria established by the American College of Radiology and the Nuclear Regulatory Commission. To the authors’ best knowledge, this has never been published in the literature. The complete protocol is provided.

Evolving Role of Magseed in Wireless Localization of Breast Lesions: Systematic Review and Pooled Analysis of 1,559 Procedures.

Wire-guided localisation (WGL) remains the most widely used technique for the localisation of non-palpable breast lesions; however, recent technological advances have resulted in non-wire, non-radioactive alternatives, such as magnetic seeds (Magseeds). The aim of this pooled analysis was to determine whether Magseeds are an effective tool for localising non-palpable breast lesions. Various databases were searched for publications which reported data on the localisation and placement rates of Magseed. Data on re-excision rates under use of Magseed and WGL were also collected. Sixteen studies, spanning the insertion of 1,559 Magseeds, were analysed. The pooled analysis showed a successful placement rate of 94.42% and a successful localisation rate of 99.86%. Four studies were analysed in a separate pooled analysis and showed no statistically significant difference between re-excision rates using Magseeds and WGL. The use of Magseeds is an effective, non-inferior alternative to WGL that overcomes many of the limitations of the latter.

P14 The use of magnetic seed for breast lesion localisation in a regional hospital: A Case Series

Background and purpose Magnetic seeds are a new and exciting technology that is starting to be used for localisation of non-palpable breast lesions. They provide an easier pathway for the patient with insertion within four weeks of the operation and reduced risk of migration compared to wire-guided localisation (James R. Harvey, 2018). They also pose no radiation risk, and do not require a destruction protocol in comparison to radioactive seeds (Magseed, 2019). Despite magnetic seeds being proven as safe and feasible (James R. Harvey, 2018), there has been little research into their effectiveness in breast lesion localisation. Our study aimed to begin to investigate the effectiveness of magnetic seeds in breast lesion localisation. Methods Our case series was a retrospective review of twenty-five cases in one peripheral hospital to investigate the clear margin rate, tumour size to specimen weight ratio and to see if there were problems with seed migration or failure of localisation. Results We found overall 64% of cases had clear margins, with 36% requiring further surgery. The rate of surgery required for extra margins was reduced further to 17.6% after the first eight cases were excluded, suggesting a learning curve. Tumour size to specimen weight ratio was 3.07. There were no concerns with seed migration and only two cases of seed localisation failure. In the two cases where the seed localisation failed, simple measures could have mitigated against this. Conclusions This case study provides further evidence that magnetic seeds are a safe and viable alternative to radioactive seeds or wire guided localization. James R. Harvey, Y. L. (2018). Safety and feasibility of breast lesion localisation using magnetic seeds (Magseed): a multi-centre, open-label cohort study. Breast Cancer Research and Treatment, 531-536.Magseed. (2019, June 20). Endomagnetics Ltd. Retrieved from Endomag: www.endomag.com.

Abstract P1-20-24: Magnetic seed localisation as the new standard of care for nonpalpable breast lesion localisation: A comparison with hooked-wire localisation

Abstract Background and aims: Breast cancer is the most frequent type of cancer diagnosed in women. In breast surgery, screening programs and high-resolution imaging result in higher incidence of impalpable breast lesions, requiring preoperative localisation. Several localisation methods have been developed during the past decades. Since September 2018, Magseed® localisation has become standard of care in University Hospitals Leuven, providing an alternative for the widely used hooked-wire localisation method. The aim of this observational study was to compare hooked-wire localisation and Magseed® localisation in terms of oncological safety, clinical safety and surgeon satisfaction. Methods: Data of 100 patients who underwent Magseed® localisation were prospectively collected between September 2018 and April 2019, and retrospectively of 91 patients who underwent hooked-wire localisation between March 2018 and September 2018. Three patients received two Magseeds® resulting in a total of 103 seeds. Similarly, 11 patients received two hooked-wires so 102 wires were included in this study. Results: Baseline patient and tumour characteristics were similar between both groups. All magnetic seeds were placed under ultrasound guidance, with a median of two days in advance, resulting in logistical ease and more patient comfort. Occurrence of haematomas did not significantly differ between Magseed® and hooked-wire placement (2.97% vs 2.13% ; p = 1.000). 96.12% of the magnetic seeds were placed within 5 mm of the target, similar to 98.04% of the hooked-wires (p = 0.683). All seeds were retrieved during surgery, with an unambiguous detection by Sentimag® in 94.06%. The median ratio excised specimen volume to initial breast volume differs significantly between both groups in favour of hooked-wire (4.5% vs 3.7% ; p = 0.049), but the specimen volume itself is almost identical between the two groups. Positive surgical margin rate was lower for Magseed® compared to hooked-wire, although not significant (4.76% vs 10.39% ; p = 0.233). Due to positive margins, one additional mastectomy was performed in the Magseed® group. In contrast, three mastectomies and one additional excision were necessary in the hooked-wire group. 81% of the Magseed® procedures were scored as ‘easier than hooked-wire’ by our surgeons. Conclusion: The positive margin rate and associated re-excision/mastectomy rate was lower with Magseed® localisation compared to hooked-wire localisation. In addition, comparison of the complication rate showed an equal clinical safety profile. Also specimen volumes are similar with both localisation techniques. Moreover, the high surgeon satisfaction and logistical advantages designate Magseed® localisation as preferable over hooked-wire localisation. Citation Format: Amelia Dehaene, Ann Smeets, Hanne Vos, Chantal Van Ongeval, Patrick Neven, Annouschka Laenen, Renate Prevos, Thomas Thywissen, Machteld Keupers, Ines Nevelsteen. Magnetic seed localisation as the new standard of care for nonpalpable breast lesion localisation: A comparison with hooked-wire localisation [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-20-24.

Magnetic Seed Localisation for Impalpable Breast Lesions is Preferred over Hooked-Wire

Magnetic Seed Localisation for Impalpable Breast Lesions is Preferred over Hooked-Wire

A German Study Comparing Standard Wire Localization With Magnetic Seed Localization of Non-palpable Breast Lesions.

Exact localization of non-palpable breast lesions is necessary to ensure that the correct lesion is removed. Conventional methods come with several disadvantages. We compared 28 patients who underwent breast-conserving surgery for a non-palpable lesion. By surgeon choice, 14 patients were assigned to undergo magnetic seed localization and 14 underwent standard wire localization. The primary outcome was the operative time, and secondary outcome was the patient pain level. The mean age was 52±10 (SD) years in the seed arm, and 55±13 years in the wire arm. The median time from skin incision to tumor extraction was not significantly different between the two groups. Patients in the wire localized group significantly more often reported pain during coughing/breathing, movement, and sleep. Using seed localization at Charité Breast Center did not lead to a significant decrease in operative time but might allow time savings once established, while increasing patient comfort and reducing organizational burden.

The Use of Magnetic Seeds and Radiofrequency Identifier Tags in Breast Surgery for Non-palpable Lesions.

Wire-guided localisation (WGL) remains the most widely used technique to guide surgical excision of non-palpable breast lesions worldwide. However, recent technological advances have led to the advent of less invasive radiation-free localisation methods to overcome the limitations of WGL. This study prospectively evaluated the role of two radiation-free non-wire localisation methods. Magnetic seeds (n=16) and radiofrequency tags (n=6) were deployed under imaging guidance to guide the surgical excision in 19 consecutive patients. The identification/retrieval and migration rates were 100% and 4.5%, respectively. Twenty-one out of 22 (95.5%) cases had clear surgical margins and no complications were observed. All radiologists and the surgeon rated these methods as being much better than wire localisation. Patient satisfaction data were recorded using a linear visual analogue scale (n=10/19). The mean score was 9.7/10 (range=8-10). Our study provides further evidence that radiation-free wireless breast localisation is an effective alternative to WGL.

Recovery of Microcrystalline Graphite from Quartz Using Magnetic Seeding

Efficient beneficiation of microcrystalline graphite remains a challenge. Selective recovery of microcrystalline graphite from quartz using hydrophobized magnetite as magnetic seed is studied in this work. Magnetite was hydrophobized by the surface coating of sodium oleate. The hydrophobic agglomerates were then separated by magnetic separation. Sedimentation experiments were performed to study the adhesion of microcrystalline graphite and quartz to magnetite particles. The results showed that hydrophobized magnetite led to a higher microcrystalline graphite recovery than that of the original magnetite, due to the higher probability to bond with microcrystalline graphite. However, the hydrophobization of the magnetite surface had an insignificant effect on its interaction with quartz. The force analysis based on the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory indicated that the total attractive interaction between hydrophobized magnetite and microcrystalline graphite were obviously stronger than that between hydrophobized magnetite and quartz, resulting in the selective aggregation between hydrophobized magnetite and microcrystalline graphite.