Applicator Design Research Articles

1668: Design and dosimetric study of a new rectal applicator for IORT treatments with the Axxent system.

1668: Design and dosimetric study of a new rectal applicator for IORT treatments with the Axxent system.

A novel 3D-printed brachytherapy applicator and Monte Carlo model for the treatment of conjunctival tumors

PurposeTo develop a custom low dose rate brachytherapy applicator for the treatment of conjunctival malignancies which leverages 3D-printing technology to provide enhanced design flexibility and availability. MethodsAn elliptical shell applicator inspired by the ocular surgery post-operation conformer shells was developed for the placement of the applicator around the cornea of the eye, with a central hole provide patient comfort. The applicator featured two concentric circles of slots for iodine-125 seeds, providing customization of the dose distribution depending on the location of the target. The applicator was modeled using computer-aided design software. The resultant model STL file was used for 3D printing of the applicator and the development of a Monte Carlo model of the applicator and its dose distribution. ResultsThe applicator was successfully 3D printed using biocompatible resin, which could be sterilized for treatment after manual source loading. A Geant4 model of the applicator was created directly from the STL model and was applied to a phantom to estimate the dose distribution delivered by the applicator. The toroidal dose distribution allowed for treatment of the conjunctiva while reducing dose to the cornea compared to traditional eye plaque designs. ConclusionsA custom 3D-printed applicator was successfully developed and modeled for the treatment of conjunctival malignancies. This novel applicator design potentially provides higher quality, more customizable dose distributions for patients and the simplicity of the design makes it accessible for any clinic with 3D-printing technology.

Helmet Radio Frequency Phased Array Applicators Enhance Thermal Magnetic Resonance of Brain Tumors.

Thermal Magnetic Resonance (ThermalMR) integrates Magnetic Resonance Imaging (MRI) diagnostics and targeted radio-frequency (RF) heating in a single theranostic device. The requirements for MRI (magnetic field) and targeted RF heating (electric field) govern the design of ThermalMR applicators. We hypothesize that helmet RF applicators (HPA) improve the efficacy of ThermalMR of brain tumors versus an annular phased RF array (APA). An HPA was designed using eight broadband self-grounded bow-tie (SGBT) antennae plus two SGBTs placed on top of the head. An APA of 10 equally spaced SGBTs was used as a reference. Electromagnetic field (EMF) simulations were performed for a test object (phantom) and a human head model. For a clinical scenario, the head model was modified with a tumor volume obtained from a patient with glioblastoma multiforme. To assess performance, we introduced multi-target evaluation (MTE) to ensure whole-brain slice accessibility. We implemented time multiplexed vector field shaping to optimize RF excitation. Our EMF and temperature simulations demonstrate that the HPA improves performance criteria critical to MRI and enhances targeted RF and temperature focusing versus the APA. Our findings are a foundation for the experimental implementation and application of a HPA en route to ThermalMR of brain tumors.

Design and Development of a Cost-Effective Transnasal Skull Base Bone Wax Applicator: A Technical Note.

Bone wax is an important hemostatic agent used in neurosurgical practice from more than a century. It acts by mechanical tamponade effect to stop the oozing from cancellous bone. Bone wax application over the skull surface over the vertex is easy and can be applied with fingers. In deeper areas, one uses dissector to apply the bone wax; however, it becomes difficult at times to apply in transnasal surgery using the same dissectors. Author designed a cost-effective 20-cm-long different angled bone wax applicator for skull base transnasal surgery. This applicator is cost-effective and not described previously in English literature.

Design and development of additivemanufactured multi-channel brachytherapy applicators for cancer treatment

Additive manufacturing (AM) is emerging as an effective manufacturing technology that benefits the medical field with its ease of quickly realizing complex designs. Brachytherapy is a process to cure cancer patients through a high dose rate of gamma radiation. This work aimed at AM-based development of multi-channel vaginal and penile brachytherapy applicators for selectively treating cancer cells in a direction sideways to the applicator rather than the uniform radiation dose possible around the conventional applicator used in cancer treatment. An analytical model was proposed to predict the maximum surface temperature on applicators during Ir-192 source radiation. Also, the predicted values of multi-physics-based finite element method simulation were experimentally validated using a thermal imaging camera. Thermal imaging is a non-contact measurement that is found superior to the brachytherapy scale to position radioactive sources inside the applicator. Experimentally examined multi-channel applicator shows dosimetry advantage in effective radiation control and shows promise of curing cancerous cells with minimal effects on normal cells.

Multibody dynamic modeling of the behavior of flexible instruments used in cervical cancer brachytherapy.

The steep radiation dose gradients in cervical cancer brachytherapy (BT) necessitate a thorough understanding of the behavior of afterloader source cables or needles in the curved channels of (patient-tailored) applicators. The purpose of this study is to develop and validate computer models to simulate: (1) BT source positions, and (2) insertion forces of needles in curved applicator channels. The methodology presented can be used to improve the knowledge of instrument behavior in current applicators and aid the development of novel (3D-printed) BT applicators. For the computer models, BT instruments were discretized in finite elements. Simulations were performed in SPACAR by formulating nodal contact force and motion input models and specifying the instruments' kinematic and dynamic properties. To evaluate the source cable model, simulated source paths in ring applicators were compared with manufacturer-measured source paths. The impact of discrepancies on the dosimetry was estimated for standard plans. To validate needle models, simulated needle insertion forces in curved channels with varying curvature, torsion, and clearance, were compared with force measurements in dedicated 3D-printed templates. Comparison of simulated with manufacturer-measured source positions showed 0.5-1.2mm median and<2.0mm maximum differences, in all but one applicator geometry. The resulting maximum relative dose differences at the lateral surface and at 5mm depth were 5.5% and 4.7%, respectively. Simulated insertion forces for BT needles in curved channels accurately resembled the forces experimentally obtained by including experimental uncertainties in the simulation. The models developed can accurately predict source positions and insertion forces in BT applicators. Insights from these models can aid novel applicator design with improved motion and force transmission of BT instruments, and contribute to the estimation of overall treatment precision. The methodology presented can be extended to study other applicator geometries, flexible instruments, and afterloading systems.

Design and performance validation of a novel 3d printed thin-walled and transparent electron beam applicators for intraoperative radiation therapy with beam energy up to 12 MeV.

A high-energy electron accelerator is used in the treatment of patients in the so-called intraoperative electron radiotherapy (IOERT). The work aimed to present the results of the validation of a new design of an electron beam applicator for use in IOERT. A novel solution was described along with the design optimization method based on Monte Carlo simulations. In this solution, the applicator consists of two parts. The lower exchangeable part collimates the therapeutic field. Measurements were made based on the International Electrotechnical Commission (IEC) standard recommendations. The measurement described in the standard has been adapted to the specificity of the intraoperative accelerator Source to Skin Distance - of 60 cm and applicators with a circular cross-sectional area. Measurements were performed for nominal beam energies of 6, 10, and 12 MeV and two therapeutic field diameters of 6 and 10 cm. The dose due to stray X-ray radiation in all energies is less than 0.3% and increases for energies from 6 to 12 MeV by 2.9 times from 0.1 for 6MeV to 0.29 for 12 MeV. The average dose due to leakage radiation also shows an increasing trend and is higher for a 6 cm diameter applicator. Validation confirmed the usefulness of the novel applicator design for clinical applications. Thanks to the use of 3D printing, it was possible to make applicators that are transparent, biocompatible and, at the same time, light and form a beam field with therapeutically useful accuracy, and the leakage radiation does not exceed normative recommendations.

Evaluating dose distributions of high dose rate 60Co brachytherapy in an asymmetric tumor: A comparison of different designs of vaginal cylindrical applicators

The aim of this study is to evaluate organ-at-risk (OAR) doses obtained from different designs of intracavitary cylinder applicators during high-dose-rate (HDR) brachytherapy of an asymmetric vaginal tumor. Dose distributions around five cylinder applicators were obtained using the Geant4 toolkit. Three of these applicators are commercially available: single-channel, multi-channel, and shielded. Additionally, two proposed sub-configurations were evaluated: (I) a combination of the multichannel applicator with a central shield and (II) a dynamically modulated cylinder (DMC). The dose distributions of the proposed applicators were compared to those of the single-channel cylinder applicator. The results showed that using a cylindrical applicator with a higher degree of freedom in plan optimization can improve OAR, sparing up to 60% for the rectum and 20% for the bladder. In conclusion, this work suggests using a new design of a cylindrical applicator to enhance the therapeutic ratio of brachytherapy for asymmetric and irregularly shaped vaginal tumors.

Design and Experiment of an Electric Control Spiral-Pushing Feed Mechanism for Field Fertilizer Applicator

Due to the unique structural characteristics of the traditional spiral fertilizer applicator, the instantaneous filling coefficient cannot be determined, which is not conducive to achieving precise control of the fertilizer discharge rate. Therefore, a spiral-pushing fertilizer applicator has been designed. By using a structure of variable diameter and variable spiral pitch to squeeze fertilizer gradually, precise control of the fertilizer discharge is achieved. The study analyzes the effects of screw pitch, screw diameter, and rotational speed on the filling coefficient; it uses spiral pitch elongation percentage, spiral diameter elongation percentage, and rotational speed as experimental factors, and filling coefficient and particle axial velocity coefficient as experimental indicators. Through quadratic orthogonal rotation combination design experiments, the fertilizer discharge performance of the spiral-pushing fertilizer applicator was optimized. The experimental results indicate that for the filling coefficient, x1x2 has an extremely significant impact, while for the axial velocity coefficient of particles, x1 and x3 have an extremely significant impact. When the rotational speed x3 is 30 r/min, the optimized spiral pitch elongation percentage x1 is 189.82–200%, the spiral diameter elongation percentage x2 is 102.75–106.76, the filling coefficient is greater than 95%, and the particle axial velocity coefficient is less than 10%, achieving the best fertilizer discharge performance. An electrically controlled fertilizer discharge system was also designed, and bench tests were conducted on it. The results show that the average deviation between the fertilizer discharge performance of the spiral-pushing fertilizer applicator driven by the electrically controlled fertilizer discharge system and the preset value is 2.14%. This proves that, when the fertilizer demand changes, the fertilizer discharge flow can be adjusted through the electrically controlled fertilizer discharge system to achieve precise fertilization. This study provides a reference for the design of spiral fertilizer applicators.

Cryolipolysis: The future of cryolipolysis.

Cryolipolysis has revolutionized the field of cosmetic dermatology as a nonsurgical procedure, utilizing controlled cooling to selectively destroy fat cells. This review article will focus on the future prospects of cryolipolysis, considering advancements in current technology as well as innovations that hold promise for the future. We will explore emerging trends in cryolipolysis, considering novel applicator designs, combination therapies, an innovative injectable treatment approach, and the evolving role of this technology in the field of cosmetic dermatology. The future holds promise for advances in cryolipolysis using both the noninvasive topical cooling approach and the novel injectable ice-slurry technology.

A Conceptual Design of a Novel Multi-Hexagonal Beta Applicator Intended to Treat Non-Melanoma Skin Cancers

Due to its short range in tissue and high dose gradient beta radiation may be used to the therapy of small and superficial skin lesions. In this short study a conceptual design of a novel multi-hexagonal beta applicator loaded with Yttrium-90 is presented. Calculations of dose rates around the applicator area performed using the beta-point source dose function formalism and initial results show that over 90\% of the beta radiation energy from the multi-hexagonal applicator loaded with Yttrium-90 is absorbed in the first layers of the skin tissue. Results show that the multi-hexagonal beta applicator has the potential to be used in the brachytherapy treatment of non-melanoma skin cancers.

Novel treatment of alopecia areata with shooting-type candlelit-dissolving microneedle

Alopecia areata (AA) is a T lymphocyte-mediated autoimmune disorder characterized by targeted hair follicle destruction that significantly affects the quality of life of patients. Conventional therapeutic strategies, including the topical application of triamcinolone acetonide (TA), face challenges owing to suboptimal cutaneous permeability and inconsistent intradermal injection techniques, which contribute to adverse effects and patient distress. In this study, we developed a shooting-type TA-encapsulated candlelit-dissolving microneedle (TCD) utilizing hyaluronic acid (HA) and polyvinylpyrrolidone (PVP) to address these limitations. In vitro evaluation using human outer root sheath cells demonstrated the ability of TCD to effectively reduce inflammation. Furthermore, in vivo analysis using a novel AA-induced C3H/HeJ mouse model revealed the efficacy of TCD in promoting hair growth and alleviating AA-related inflammatory processes. This innovative TCD applicator design overcomes the shortcomings of the prevailing TA treatments and provides a promising alternative approach for enhanced AA management. This study lays a foundation for future research focusing on optimizing TCD, assessing its long-term efficacy, and exploring its applicability in the treatment of other dermatological conditions. By integrating cutting-edge scientific discoveries, TCD can improve AA treatment outcomes.

Design and Optimization of Sugarcane Spiral Fertilizer Applicator Based on Response Surface Methodology and Artificial Neural Networks

To address the challenges of poor fluidity and low uniformity in conventional sugarcane fertilizer applicators, a novel dual-directional spiral fertilizer applicator has been developed. The working principle of the applicator is explained, and, after analyzing the agronomic requirements for sugarcane, the parameter range for key components of the applicator is determined. The spiral blade’s diameter, pitch, and rotational velocity are chosen as the experimental factors, with the average fertilizer discharge uniformity as the evaluation criterion. Virtual simulation experiments are conducted using the discrete element method and a quadratic regression orthogonal rotating combined design. Regression models for the evaluation criterion and various experimental factors are obtained. Additionally, a dataset created from these experiments was then used to construct an artificial neural network (ANN) prediction model. Response surface methodology (RSM) and the ANN were both used to analyze and predict the outcomes. The results indicate that the artificial neural network outperforms response surface methodology in terms of better fitting capability and higher prediction accuracy. The determination coefficient, mean squared error, and root mean square error are 0.99629, 0.99163, 0.07763, 0.17498, 0.27862, and 0.41831, respectively. When comparing the two models, the optimal parameter combination is determined to be a diameter of 90.1669 mm, a pitch of 59.7407 mm, and a rotational speed of 53.8944 r/min, resulting in an average fertilizer discharge uniformity of 92.0670%. An experiment with these parameters confirmed the simulated findings, revealing a maximum discrepancy of 2.4%. This study offers valuable insights into optimizing spiral fertilizer applicators.

A Novel Multi-Channel Tandem Applicator for Direction Modulated Brachytherapy

Intracavitary brachytherapy is a fundamental part of the treatment of cervical cancer that would be applied as boost therapy. However, the coverage of non-uniform targets is very challenging for this technique when dealing with the lateral extension of tumor, particularly when the tumor is too far superiorly to be covered by radiation dose from the ovoids or rings. In such situations, the conventional (single channel) tandem applicator would need to effectively provide the entire dose to the region yet have a very limited capacity for the intensity modulation due to the isotropic nature of radiation from the 192Ir HDR source. This limitation would require development of state-of-the-art interstitial-intercavitary applicators. In this study we aim to introduce a novel multi-channel tandem applicator design in alignment with the direction modulated brachytherapy (DMBT) concept to address this important issue. The novel multi-channel tandem applicator was designed using GEANT4 Monte Carlo simulations to consist of a base, made of MR compatible PEEK plastic, with a diameter of 6.5 mm and 19 channels each 1.1 mm in diameter, and in a honeycomb arrangement. The design also incorporated 18 iridium wires with a diameter of 0.9 mm that can actively enter the channels to provide intensity modulation at desired directions. A dosimetry study was then performed with different configurations of the 192Ir HDR source, also 0.9 mm in diameter, and up to 18 iridium wires inside the base. While offering the symmetrical dose distribution of the conventional tandem, the honeycomb design could produce a variety of directional dose distributions with different degree of extended lateral coverage. Additionally, this novel design with the configuration of 18 iridium wires inside the base covering the HDR source could reduce the radiation dose to approximately 15 % behind the shielded side at 1 cm from the tandem compared to the unshielded side. The results indicated that the honeycomb DMBT tandem design, as a noninvasive intracavitary approach, could be a promising solution for covering targets with lateral asymmetry/extension. Utilizing high-density material such as tungsten as the base material could reduce the radiation leakage through the base, improve the intensity modulation and hence lateral coverage.

120 Design of Patient Specific Multi-Catheter Gynecological Brachytherapy Applicators with Customizable Catheter Positions

120 Design of Patient Specific Multi-Catheter Gynecological Brachytherapy Applicators with Customizable Catheter Positions

Histology-Validated Dielectric Characterisation of Lung Carcinoma Tissue for Microwave Thermal Ablation Applications.

Microwave thermal ablation is a promising emerging treatment for early-stage lung cancer. Applicator design optimisation and treatment planning rely on accurate knowledge of dielectric tissue properties. Limited dielectric data are available in the literature for human lung tissue and pulmonary tumours. In this work, neoplastic and non-neoplastic lung dielectric properties are characterised and correlated with gross and histological morphology. Fifty-six surgical specimens were obtained from twelve patients undergoing lung resection for lung cancer in University Hospital of Galway, Ireland. Dielectric spectroscopy in the microwave frequency range (500 MHz-8.5 GHz) was performed on the ex vivo lung specimens with the open-ended coaxial probe technique (in the Department of Pathology). Dielectric data were analysed and correlated with the tissue histology. The dielectric properties of twelve lung tumours (67% non-small cell carcinoma (NSCC)) and uninvolved lung parenchyma were obtained. The values obtained from the neoplastic lung specimens (relative permittivity: 52.0 ± 5.4, effective conductivity: 1.9 ± 0.2 S/m, at 2.45 GHz) were on average twice the value of the non-neoplastic lung specimens (relative permittivity: 28.3 ± 6.7, effective conductivity: 1.0 ± 0.3 S/m, at 2.45 GHz). Dense fibrosis was comparable with tumour tissue (relative permittivity 49.3 ± 4.6, effective conductivity: 1.8 ± 0.1 S/m, at 2.45 GHz).

Comparison of Microwave Hyperthermia Applicator Designs with Fora Dipole and Connected Array.

In microwave hyperthermia tumor therapy, electromagnetic waves focus energy on the tumor to elevate the temperature above its normal levels with minimal injury to the surrounding healthy tissue. Microwave hyperthermia applicator design is important for the effectiveness of the therapy and the feasibility of real-time application. In this study, the potential of using fractal octagonal ring antenna elements as a dipole antenna array and as a connected array at 2.45 GHz for breast tumor hyperthermia application was investigated. Microwave hyperthermia treatment models consisting of different fractal octagonal ring antenna array designs and a breast phantom are simulated in COMSOL Multiphysics to obtain the field distributions. The antenna excitation phases and magnitudes are optimized using the global particle swarm algorithm to selectively increase the specific absorption rate at the target region while minimizing hot spots in other regions within the breast. Specific absorption rate distributions, obtained inside the phantom, are analyzed for each proposed microwave hyperthermia applicator design. The dipole fractal octagonal ring antenna arrays are comparatively assessed for three different designs: circular, linear, and Cross-array. The 16-antenna dipole array performance was superior for all three 1-layer applicator designs, and no distinct difference was found between 16-antenna circular, linear, or cross arrays. Two-layer dipole arrays have better performance in the deep-tissue targets than one-layer arrays. The performance of the connected array with a higher number of layers exceeds the performance of the dipole arrays in the superficial regions, while they are comparable for deep regions of the breast. The 1-layer 12-antenna circular FORA dipole array feasibility as a microwave hyperthermia applicator was experimentally shown.

Advanced Radio Frequency Applicators for Thermal Magnetic Resonance Theranostics of Brain Tumors

Thermal Magnetic Resonance (ThermalMR) is a theranostic concept that combines diagnostic magnetic resonance imaging (MRI) with targeted thermal therapy in the hyperthermia (HT) range using a radiofrequency (RF) applicator in an integrated system. ThermalMR adds a therapeutic dimension to a diagnostic MRI device. Focused, targeted RF heating of deep-seated brain tumors, accurate non-invasive temperature monitoring and high-resolution MRI are specific requirements of ThermalMR that can be addressed with novel concepts in RF applicator design. This work examines hybrid RF applicator arrays combining loop and self-grounded bow-tie (SGBT) dipole antennas for ThermalMR of brain tumors, at magnetic field strengths of 7.0 T, 9.4 T and 10.5 T. These high-density RF arrays improve the feasible transmission channel count, and provide additional degrees of freedom for RF shimming not afforded by using dipole antennas only, for superior thermal therapy and MRI diagnostics. These improvements are especially relevant for ThermalMR theranostics of deep-seated brain tumors because of the small surface area of the head. ThermalMR RF applicators with the hybrid loop+SGBT dipole design outperformed applicators using dipole-only and loop-only designs, with superior MRI performance and targeted RF heating. Array variants with a horse-shoe configuration covering an arc (270°) around the head avoiding the eyes performed better than designs with 360° coverage, with a 1.3 °C higher temperature rise inside the tumor while sparing healthy tissue. Our EMF and temperature simulations performed on a virtual patient with a clinically realistic intracranial tumor provide a technical foundation for implementation of advanced RF applicators tailored for ThermalMR theranostics of brain tumors.

Global sensitivity study for irreversible electroporation: Towards treatment planning under uncertainty.

Electroporation-based cancer treatments are minimally invasive, nonthermal interventional techniques that leverage cell permeabilization to ablate the target tumor. However, the amount of permeabilization is susceptible to the numerous uncertainties during treatment, such as patient-specific variations in the tissue, type of the tumor, and the resolution of imaging equipment. These uncertainties can reduce the extent of ablation in the tissue, thereby affecting the effectiveness of thetreatment. The aim of this work is to understand the effect of these treatment uncertainties on the treatment outcome for irreversible electroporation (IRE) in the case of colorectal liver metastasis (CRLM). Understanding the nature and extent of these effects can help us identify the influential treatment parameters and build better models for predicting the treatmentoutcome. This is an in silico study using a static computational model with a custom applicator design, spherical tissue, and tumor geometry. A nonlinear electrical conductivity, dependent on the local electric field, is considered. Morris analysis is used to identify the influential treatment parameters on the treatment outcome. Seven treatment parameters pertaining to the relative tumor location with respect to the applicator, the tumor growth pattern, and the electrical conductivity of tissue are analyzed. The treatment outcome is measured in terms of the relative tumor ablation with respect to the target ablation volume and total ablationvolume. The Morris analysis was performed with 800 model evaluations, sampled from the seven dimensional input parameter space. Electrical properties of the tissue, especially the electrical conductivity of the tumor before ablation, were found to be the most influential parameter for relative tumor ablation and total ablation volume. This parameter was found to be about 4-15 times more influential than the least influential parameter, depending on the tumor size. The tumor border configuration was identified as the least important parameter for treatment effectiveness. The most desired treatment outcome is obtained by a combination of high healthy liver conductivity and low tumor conductivity. This information can be used to tackle worst-case scenarios in treatment planning. Finally, when the safety margins used in the clinical applications are accounted for, the effects of uncertainties in the treatment parameters reducedrastically. The results of this work can be used to create an efficient surrogate estimator for uncertainty quantification in the treatment outcome, that can be utilized in optimal real-time treatment planning solutions.

Structural design optimization and lipolytic effect prediction of vacuum suction cryolipolysis applicator: Simulation study.

Cryolipolysis is a popular noninvasive lipolytic method that uses low temperature to induce apoptosis or necrosis of adipocytes to reduce local fat in the human body. Vacuum suction applicator is a commonly used cryolipolysis equipment, which suction human skin and fat into a chamber for cooling. The structure of vacuum suction applicator is usually irregular, its cooling characteristic is also complex, and unreasonable suction structure will cause human discomfort. Biological experiments and clinical studies are often used to study the structural design of applicators, whereas these methods are impossible to obtain the three-dimensional cooling characteristic of applicator comprehensively and require a lot of costs. This study aims to optimize the structure of applicator for lowering discomfort, evaluate the cooling characteristic and lipolytic effect of applicators, which could provide guidance for clinical application of applicators and reduce costs. Cryolipolysis applicators models with four vacuum suction angles were established, and COMSOL was used to compare the cooling performance parameters, cooling kinetics, and lipolytic effects of the applicators. Specific evaluation indicators also include: cooling capacity analysis, temperature field analysis, lipolytic percentage, lipolytic volume, lipolytic weight, lipolytic thickness, lipolytic waistline, and lipolysis temperature threshold analysis. The applicator with a small suction angle has a greater cooling capacity to cool deeper level of fat. When the cooling temperature is -10°C, the temperature of skin layer is about -10°C at 60 minutes, the temperature of fat layer is -7.36 to 3.01°C at 10 mm, -3.67 to 5.91°C at 20 mm and 2.01-10.81°C at 30 mm. The percentage of lipolytic declined with the increase of suction angle, the final lipolytic percentage (35.81%) of the 90° applicator is the highest, the percentage (28.72%) of 150° applicator (28.72%) is the lowest. The lipolytic volume, weight, and average thickness of applicator constantly increased with the increase of the suction angle, the final lipolytic volume range of the four suction angle applicators is 171.88-310.18 cm3 , the lipolytic weight range is 160.11-288.93 g, and the lipolytic average thickness range is 1.21-1.36 cm. Lower lipolysis temperature threshold will reduce the lipolysis effect, but it may also lead to another lipolysis mechanism-cell necrosis. Different suction angles significantly affect the cooling characteristics and lipolytic effects of cryolipolysis applicator. A reasonable suction angle is one of the critical factors to improve the efficiency and comfort of cryolipolysis.