Subcutaneous Fat Layer Research Articles

Reliability of body composition assessment using A-mode ultrasound in a heterogeneous sample

Background/ObjectivesSeveral studies have addressed the validity of ultrasound (US) for body composition assessment, but few have evaluated its reliability. This study aimed to determine the reliability of percent body fat (%BF) estimates using A-mode US in a heterogeneous sample.Subjects/MethodsA group of 144 healthy adults (81 men and 63 women), 30.4 (10.1) years (mean (SD)), BMI 24.6 (4.7) kg/m2, completed 6 consecutive measurements of the subcutaneous fat layer thickness at 8 anatomical sites. The measurements were done, alternatively, by two testers, using a BodyMetrix™ instrument. To compute %BF, 4 formulas from the BodyView™ software were applied: 7-sites Jackson and Pollock, 3-sites Jackson and Pollock, 3-sites Pollock, and 1-point biceps.ResultsThe formula with the most anatomic sites provided the best reliability quantified by the following measures: intraclass correlation coefficient (ICC) = 0.979 for Tester 1 (T1) and 0.985 for T2, technical error of measurement (TEM) = 1.07% BF for T1 and 0.89% BF for T2, and minimal detectable change (MDC) = 2.95% BF for T1, and 2.47% BF for T2. The intertester bias was −0.5% BF, whereas the intertester ICC was 0.972. The intertester MDC was 3.43% BF for the entire sample, 3.24% BF for men, and 3.65% BF for women.ConclusionsA-mode US is highly reliable for %BF assessments, but it is more precise for men than for women. Examiner performance is a source of variability that needs to be mitigated to further improve the precision of this technique.

Performance of near-infrared spectroscopy in pork shoulder as a predictor for pork belly softness

Pork belly quality indicators are economically relevant in the pork industry. Near-infrared (NIR) spectroscopy of the pork shoulder outer subcutaneous fat layer, belly flop angle, and subjective softness scores of the pork belly were measured (N = 144) to determine the accuracy of pork shoulder NIR spectroscopy as a predictor of pork belly softness. The NIR spectra hot carcass estimates explained over 80.0% variability in pork belly softness (80.5%–90.8%), with low prediction error, suggesting that NIR spectroscopy measured in the pork shoulder is an efficient and accurate indicator of pork belly softness to classify pork bellies for specific market demands.

A case of supravaginal amputation of the uterus. Intraperitoneal method. Recovery

On February 19, 1890, patient EI, 50 years old, was admitted to the hospital, extremely exhausted; subcutaneous fat layer is poorly developed, visible mucous membranes are pale. Regula appeared at the age of 15, the first birth at the age of 21. Dysmenoric phenomena, which appeared 10 years ago, have significantly increased since last summer. Pain is localized mainly in the left groin area. Hemorrhages have become more profuse, showing almost daily lately. An objective examination revealed a tumor in the lower abdomen, completely smooth, uniformly dense consistency, the size of a child's head. The body of the uterus is directly connected to it. The outer opening of the portionis vaginalis passes the tip of the finger. The vaults are free.

Lipoatrophy in children, adolescents and adults with insulin pump treatment: Is there a beneficial effect of insulin glulisine?

To investigate whether zinc-free insulin is an effective treatment option for lipoatrophy. Controlled, randomized, open-label parallel study in young people with type 1 diabetes, pump treatment and lipoatrophy at injection sites. Participants underwent dermatological examination and evaluation of affected areas using ultrasound and magnetic resonance imaging (MRI). After randomization, half of themswitched to insulin glulisine (intervention group) for 6 months. The control group continued their treatment with zinc-containing insulin and switched to insulin glulisine 6 months later. Both groups were followed-up until month 12. Primary endpoint was the increase of the relative thickness of the subcutaneous fat layer of the most atrophic site at 6 months as documented by MRI. Fourteen participants were included into the study. While relative thickness of subcutaneous fat tissue was comparable between intervention (-60% [-98.8 - -17.6], n = 7) and control group (-50% [-72.7 - -1.0], P = .511; median (range), n = 7)at baseline, it improved in the intervention (-14.3% [-85.7-83.3] vs -31.3% (-66.7-0), P = .031), but not in the control group (P = .125) after 6 months. At 12 months, relative fat thickness (P = .003), number (P = .015) and size of most atrophic sites (P = .001) were improved in the intervention group. Number (P = .018) and size of most atrophic sites (P = .008) were also reduced in the control group between 6 and 12 months. Although the present pilot study is based on a small sample, the data give first hint that the use of the zinc-free insulin glulisine may be beneficial in people with diabetes, pump and lipoatrophy.

The association of serum vascular endothelial growth factor levels and psoriasis vulgaris: A protocol for systematic review and meta-analysis.

Background:In recent years, more and more attention has been paid to the role of skin microcirculation in the pathogenesis of psoriasis. The vascular network of the skin is mainly distributed in the dermis and the subcutaneous fat layer join. The microvessels are composed of terminal arterioles, arteriovenous capillaries, and postcapillary venules. Vascular endothelial growth factor (VEGF) plays an important role in the pathogenesis of psoriasis by promoting angiogenesis. The purpose of this study is to evaluate the relationship between serum VEGF and psoriasis vulgaris.Methods:Embase, CENTRAL, PubMed, China Biology Medicine Database, China National Knowledge Database, Wan Fang Database, and Chong Qing VIP Database will be searched to collect case-control studies and cohort studies and evaluate the relationship between serum VEGF and psoriasis vulgaris. The search time limits will be from the establishment of the database to December 2020. Two researchers will independently screen the studies, extract data, and evaluate the risk of bias of the studies. The Meta-analysis will be carried out with the RevMan5.3 software. The quality of all included studies will be evaluated by the Newcastle-Ottawa scale.Results:This study will evaluate the relationship between serum VEGF and the pathogenesis of psoriasis vulgaris.Conclusion:This study will provide a theoretical basis for the pathogenesis of psoriasis vulgaris.OSF registration number:DOI 10.17605/OSF.IO/6DV8P

Preclinical evaluation for removal of bulging lower eyelid fat using ultrasound-assisted lipolysis on a Yorkshire pig.

The purpose of this study is to evaluate the efficacy and safety of treating lower eyelid fat bulging with ultrasound-assisted lipolysis (UAL) by performing a preclinical evaluation of the procedure on a Yorkshire pig. Two white Yorkshire pigs had lower eyelid fat bulging treated with UAL using a probe with a diameter of 1.0mm or less. Fourteen days after treatment, we evaluated the changes in fat thickness from ultrasound, changes in skin contour (volume and height) from the Antera 3D™, and the disruption of fat cells and changes in collagen synthesis from histological evaluation. Fourteen days after treatment, the fat layer was significantly reduced with no damage to the skin surface. The mean change in the subcutaneous fat layer thickness was decreased 1.51-0.75mm in ultrasound analysis. The skin contour of the treated area also decreased with time from 202.5 to 163.5mm in mean volume and 0.8111 to 0.646mm in mean height. Masson's trichrome staining showed that the UAL treatment induced the regeneration and remodeling of collagen. The results of this study demonstrate that UAL successfully reduced the bulging lower eyelid fat of a Yorkshire pig and also increased collagen contraction to tighten skin. UAL may be a beneficial and well-tolerated treatment option for lower eyelid fat bulging.

Therapeutic Effects against Tissue Necrosis of Remote Ischemic Preconditioning Combined with Human Adipose-Derived Stem Cells in Random-Pattern Skin Flap Rat Models

Introduction Remote ischemic preconditioning (rIPC) is a preventive strategy against ischemia–reperfusion injury. To reduce ischemia–reperfusion injury of random-pattern skin flaps, we investigated the therapeutic effects of rIPC combined with human adipose-derived stem cells (hADSCs) in a rat model. Material and Methods In total, 24 female Sprague Dawley rats were divided into four groups (n = 6 each): control (skin flap only), rIPC, hADSCs, and rIPC + hADSCs. rIPC was performed in the hind limb of the rats over three cycles of 5 min of occlusion and 5 min of reperfusion, using a tourniquet. A rectangular (3 × 9 cm) dorsal skin flap was used. hADSCs (5 × 105 cells/100 µL) labeled with fluorescent dye were transplanted into the normal subcutaneous tissue at the skin flap boundary. After 14 days, the therapeutic effects of rIPC and hADSCs were evaluated via analysis of the necrotic flap area, histopathologic assessment, and immunohistochemistry (von Willebrand Factor (vWF) and CD31). Results The necrotic area of the skin flap significantly decreased in the rIPC + hADSCs group (32.75 ± 1.43%) compared with the control (40.60 ± 3.27%, P < 0.01) and rIPC groups (38.84 ± 0.77%, P < 0.05). Dye-labeled hADSCs migrated to the skin flap from the injection site. In the rIPC + hADSCs group, the epithelial tissue and skin appendage had regenerated, and the smooth muscle and subcutaneous fat layers were preserved. Many more vWF- and CD31-positive vessels were observed in the rIPC + hADSCs group compared with the other groups. Conclusions The rIPC + hADSCs treatment appeared to reduce skin flap necrosis and activated neovascularization in rats. Therefore, it may be a good strategy for clinical treatment of ischemia–reperfusion injury.

Development of a hand-held magnetic resonance sensor for the nondestructive quantification of fat and lean meat of fresh tuna

For the in-situ nondestructive fat quantification of fresh tuna meat, an original lightweight (5.7 kg) hand-held sensor that consists of a planar radio-frequency coil and a single-sided magnetic circuit was developed as a subunit of a time-domain proton magnetic resonance (MR) scanner system. The investigation depth of the sensor unit is 12 mm, which is sufficient to probe the meat section beneath thick skin with scales and the underlying subcutaneous fat layer of large fish such as tuna. The scanner was successfully applied in a laboratory to a fillet of a bluefin tuna (Thunnus thynnus) to measure meat sections 12 mm beneath the skin. The required measurement time was 100 s for each section. The results of MR scan at 11 locations on the fillet were compared with those of conventional destructive food analysis. Reasonable agreement with an error (root-mean-square residual) of as small as 1.8 wt% was obtained for fat quantification. The time-domain MR relaxometry for the same tuna fillet also allowed lean meat quantification with a small root-mean-square residual of 6.7 wt%.

Are We over Dissecting the Cord in Orchidopexy?

Background: Orchidopexy is a procedure of securing the testis inside the scrotum in patients with cryptorchidism. In the literature, various dissection techniques have been described to lengthen the spermatic cord to ensure a tension-free fixation of the testis to the lowest point of the scrotum.Objectives: The aim of this study is to determine if incorrect measurement of the spermatic cord’s length during open inguinal orchidopexy had led surgeons to over dissect the cord in a way that may pose an increased risk of testes, vas deferens and spermatic vessels.Materials and Methods: We prospectively studied the results of 40 orchidopexies performed in 40 patients with peeping or canalicular undescended testis , which was done at the Jordan university hospital in Amman from April 2018 to March 2019 , We compared the position of the testis before and after tunneling inside the inguinal canal. The difference in length is measured and analyzed.Conclusion: Failure to account for the subcutaneous fat layer thickness during orchidopexy increases the likelihood of over dissecting the spermatic cord which increases the risk of vas and vessels injury In this study we found that there is a difference between the cord length outside and inside the canal with excess length after passing the cord inside the canal ranges from 1-3 cm . This means that we do not need to dissect the cord to make the testis reaches the scrotum from outside. This decreases the risk of harming the cord and its contents.

Gain without pain: beyond sport effortless exercise solutions

Ageing is associated with decreased metabolism, increased toxicity, decreased skeletal muscle mass (SMM) and increased visceral fat deposits that compromise the normal functioning of vital organs such as the liver, pancreas and intestines, increasing the risk of a number of health problems, including type 2 diabetes, coronary heart disease, hypertension and non-alcoholic fatty liver. Visceral adipose tissue holds large amounts of toxins that alter thyroid hormone metabolism, lowering resting metabolic rate (RMR). Strenuous physical exercise can reach these deeper visceral adipose tissue layers. However, excessive exercise is necessary to reduce visceral adipose tissue elevates cortisol while decreasing testosterone. The hormonal imbalance resulting from this inverse cortisol/testosterone relationship ultimately leads to weight gain, despite all the efforts invested in physical activity. On the other hand, lack of exercise allows for accumulation of toxicity and increased vulnerability to chronic physical disorders. Energy-based technologies report successful results in reducing subcutaneous fat layers; however, data is not currently available about methods that can reduce deeper visceral adipose tissue and relieve the system from visceral fat cells stuffed with excess triglycerides. In this study, we examined hormone and cholesterol fluctuations in the blood tests of eight subjects undergoing six 45 minutes of effortless exercise sessions with a novel London University invention. We also explored changes in their visceral adipose tissue, overall body fat mass, SMM, basic metabolic rate (BMR), waist and abdomen reduction in centimetres (cm) and overall weight loss in kilograms (kg). Subjects' results revealed a statistically significant increase in triiodothyronine (Free T3), accompanied by a significant decrease in the very low-density lipoprotein (VLDL) and triglycerides. Cortisol did not show statistically significant fluctuations. There was a statistically significant decrease in visceral adipose tissue and overall body fat mass and a statistically significant increase in SMM. Waist and abdomen cm loss, and weight loss in kgs were statistically significant, demonstrating a substantial decrease in cm and kgs in all subjects that persisted a week after the last treatment. Results of this study supported the hypothesis that this method of effortless exercise can reduce both overall body fat mass, visceral adipose tissue and VLDL, while increasing SMM and the metabolic hormone free T3, without the aid of diet or change in lifestyle.

674-P: Missed Diagnosis of Lipohypertrophy by Inspection and Palpation: Prevalence and Contributing Risk Factors

Background: Lipohypertrophy (LH) is harmful and requires early diagnosis. While LH is typically detected by inspection and palpation (physical examination), the reliability is potentially low. We evaluated the prevalence and contributing risk factors for missed LH compared to ultrasound scanning (USS). Methods: This was a cross-sectional study included 260 patients who had injected insulin continuously for at least 1 year. Physical examination and USS were used meanwhile. Associations between missed diagnosis and clinical, injection behavioral variables were examined. Results: Patients were 40.4 ± 23.7 years old, 52.7% male, 50.8% type 1 diabetes. 80.8% were diagnosed with LH by USS, that three characteristics are significant thickening of the subcutaneous fat layer; increased echogenicity in diffuse areas; nodular hyperechoic foci. Physical examination resulted in a 39.0% false negative rate. By stepwise logistic regression, duration of insulin therapy modestly associated with missed diagnosis of LH (odds ratios [OR] = 0.84, P &amp;lt; 0.001); Higher BMI and correct site rotation showed ORs of 3.02 (P = 0.005) and 3.67 (P &amp;lt; 0.001), respectively. Conclusions: Physical examination was associated with a high rate of missed LH diagnosis for patients received insulin for a short duration, higher BMI etc. Ultrasound scanning should be used as a complementary technique. Disclosure J. Xu: None. D. Luo: None. H. Wang: None. M. Zhu: None. Y. Shi: None.

Pump Insulin Therapy and Continuous Glycemic Monitoring

Diabetes mellitus is a chronic disease, which is based on insufficient insulin production, which ultimately leads to the development of hyperglycemia. As a result of the continuous increase in blood sugar levels, many organs and systems suffer, and diabetes is one of the common causes of disability. After the discovery of the true nature of the disease, the main method of treatment is the administration of insulin. The dose and frequency of administration of this drug are selected individually and can be adjusted during treatment. The insulins used at the present stage are represented by ultra-short, short-acting, mediumduration and slow-acting drugs. Ultrashort and short-acting insulins begin to work literally in a few minutes after administration, but the effect persists for a short time. This type of insulin is indicated for subcutaneous administration before meals or immediately after it. Medium and slow-acting insulins are meant to maintain insulin at a certain level for a long time, they are administered at the same time, usually twice a day. Short and ultrashort insulins should be injected into the subcutaneous tissue of the abdomen, while taking into account that the greater the thickness of the subcutaneous fat layer, the slower the absorption. Slow-acting insulins are recommended to be administered to the outer surface of the thigh or buttocks. Insulin is administered using insulin syringes or pen injectors. At present, the use of insulin pumps, which provide continuous supply of insulin using a special device, has become an alternative to the syringe administration of short-acting and ultra-short insulins. Often, such devices are equipped with glucose level sensors, which allows continuous monitoring of blood sugar levels.

Human‐Palm‐Inspired Artificial Skin Material Enhances Operational Functionality of Hand Manipulation

AbstractHuman skin plays an important role in hand manipulation by making a stable grasp with an enlarging contact area while providing a firm hold on the object. However, satisfying these two functions is contradictory in conventional single‐layer artificial skin. Softer skin material would increase the contact area, which is advantageous in maintaining the stability, but it decreases the manipulability since the object tends to make uncontrollable movement within the softer skin, and vice versa for harder skin material. This paper presents a biomimetic three‐layer skin structure inspired by human palm skin and shows that both stability and manipulability can be enhanced with the three‐layer structure. To achieve the unique stiffness characteristics of the human palm skin, a porous latex structure, which is highly compressible but tough in tensile direction, is chosen as the subcutaneous fat layer. Through the novel experimental setup and the finite element method simulations, it is found that the porous latex structure is the key structure contributing to both stability and manipulability. Furthermore, it is demonstrated that a robotic hand with the proposed skin material shows enhanced robustness in grasping tasks. With the proposed skin material, the robotic hands would be more advantageous for challenging manipulation tasks.

MRI로 측정한 하지의 피하 지방두께와 근육량이 sEMG 진폭에 미치는 영향

The study was conducted to see if the subcutaneous fat thickness of the thigh measured by the MRI affects the Cross-Sectional Area(CSA) and surface-electromyography(sEMG). To achieve the goal, 79 adult men and women were analyzed for correlation by measuring the maximum and average muscular activity of inner and vastus medialis oblique(VMO) and vastus lateralis(VL) that occur during MRI and squats, including BMI, and the following conclusions were drawn.<BR> First, the subcutaneous fat layer had an adverse effect on the sEMG of the VMO muscle that occurred during squatting. Second, the CSA of the VMO muscle did not affect the sEMG. Third, the subcutaneous fat layer had an adverse effect on the sEMG of the VL that occurs during squats operation. Fourth, the CSA of the VL did not affect the sEMG. Fifth, BMI is related to CSA, but not to subcutaneous fat layer.

MRI pattern changes in pelvic muscle and lower limb in patients with dysferlinopathy

Introduction . Dysferlinopathy is a phenotypically heterogeneous group of hereditary muscular dystrophies caused by mutations in the dysferlin gene ( DYSF ). Debut in adolescence, predominantly in physically developed patients, combined with the often subacute development of hypercreatine phosphatemia and edematous muscle changes in MRI often leads to diagnostic errors. Purpose of the study : to determine the most typical MRI pattern of muscle damage of the pelvic girdle and lower limb in patients with dysferlinopathy. Materials and methods . 40 people were examined, among which 20 patients with a clinical picture of dysferlinopathy with an equal ratio of Miyoshi phenotypes and LGMD and an average age of 35 (24; 44) years. Comprehensive clinical and instrumental examination included neurological, electroneuromyographic and molecular genetic studies (NGS). Magnetic resonance imaging of the muscles of the pelvic girdle and lower limb was performed in 20 patients and a control group equivalent in sex and age. Results . The use of semi-quantitative MRI indicators — relative signal intensity — D (D=T1 muscle (STIR) / T1 (STIR) subcutaneous fat layer) made it possible to formulate the characteristics of a common typical MRI pattern of muscle involvement in dysferlinopathy. An increase in the intensity of the relative signal D, T1 in the rear muscle group of the thighs and lower legs, indicating fatty infiltration was observed most frequently, while a decrease in D, STIR values was observed in the anterior and medial muscles of the thighs, reflecting the presence of edema of the previous fatty degeneration of these muscles. Conclusion . In addition to the general idea of muscle involvement in dysferlinopathy, it is advisable to consider the «early», «typical / completed» and «late» MRI patterns of dysferlinopathy that increase the effectiveness of the diagnosis of this disease. In the differential diagnosis of the Miyoshi phenotype from LGMD, one should focus on maintaining normal values of D, T1 from m. gluteus maximus and m. popliteus at all stages of the disease.

Optically tracked and 3D printed haptic phantom hand for surgical training system.

For surgical fixation of bone fractures of the human hand, so-called Kirschner-wires (K-wires) are drilled through bone fragments. Due to the minimally invasive drilling procedures without a view of risk structures like vessels and nerves, a thorough training of young surgeons is necessary. For the development of a virtual reality (VR) based training system, a three-dimensional (3D) printed phantom hand is required. To ensure an intuitive operation, this phantom hand has to be realistic in both, its position relative to the driller as well as in its haptic features. The softest 3D printing material available on the market, however, is too hard to imitate human soft tissue. Therefore, a support-material (SUP) filled metamaterial is used to soften the raw material. Realistic haptic features are important to palpate protrusions of the bone to determine the drilling starting point and angle. An optical real-time tracking is used to transfer position and rotation to the training system. A metamaterial already developed in previous work is further improved by use of a new unit cell. Thus, the amount of SUP within the volume can be increased and the tissue is softened further. In addition, the human anatomy is transferred to the entire hand model. A subcutaneous fat layer and penetration of air through pores into the volume simulate shiftability of skin layers. For optical tracking, a rotationally symmetrical marker attached to the phantom hand with corresponding reference marker is developed. In order to ensure trouble-free position transmission, various types of marker point applications are tested. Several cuboid and forearm sample prints lead to a final 30 centimeter long hand model. The whole haptic phantom could be printed faultless within about 17 hours. The metamaterial consisting of the new unit cell results in an increased SUP share of 4.32%. Validated by an expert surgeon study, this allows in combination with a displacement of the uppermost skin layer a good palpability of the bones. Tracking of the hand marker in dodecahedron design works trouble-free in conjunction with a reference marker attached to the worktop of the training system. In this work, an optically tracked and haptically correct phantom hand was developed using dual-material 3D printing, which can be easily integrated into a surgical training system.

Evaluation of the racial difference in body condition score and parameters of lipid metabolism in Purebred Arabian horses and Thoroughbred horses trained for racing

This study investigated the existence of difference of fat deposition and lipid metabolism in horses with different races and skills that were used for the same kind of sport. 20 Purebred Arabian and 20 Thoroughbred horses trained for flat race were evaluated. The analyses performed were body condition score, weight and blood collected for determination of triglycerides, total cholesterol and non-esterified fatty acids. Ultrasonography of the thickness of the subcutaneous fat layer was performed on the Longissimus dorsi muscle between the 17th and 18th rib, the thickness of the subcutaneous fat layer on the Gluteus medius muscle using the acetabulum as reference, and the cross section of the same muscle. Race-trained Arabian horses showed greater fat layer deposition in the Gluteus medius and Longissimus dorsei musclesthan Thoroughbred horses. These facts indicate that there is a metabolic difference, besides the phenotype, between the races. They also indicate the need to study specific physical conditioning programs for each kind of race.

Effects of neuromuscular electrical stimulation training on muscle size in collegiate track and field athletes

The purpose of this study was to examine the effects of neuromuscular electrical stimulation training for 12 weeks on the abdominal muscle size in trained athletes. Male collegiate track and field athletes participated in the present study and were randomly allocated to either training or control groups. Eleven participants of the training group completed a 60-session training program over a 12-week period (23 min/session, 5 days/week) involving neuromuscular electrical stimulation (mostly 20 Hz) for the abdominal muscles in addition to their usual training for the own events. The participants of the control group (n = 13) continued their usual training. Before and after the intervention period, cross-sectional areas of the rectus abdominis and abdominal oblique muscles (the internal and external obliques and transversus abdominis) and subcutaneous fat thickness were measured with magnetic resonance and ultrasound imaging. There were no significant changes in cross-sectional area of the rectus abdominis or abdominal oblique muscles or in subcutaneous fat thickness in the training or control groups after the intervention period. The change in cross-sectional area of the rectus abdominis in each participant was not significantly correlated with pre-training cross-sectional area and neither was the mean value of fat thickness at pre- and post-training. These results suggest that low-frequency (20 Hz) neuromuscular electrical stimulation training for 12 weeks is ineffective in inducing hypertrophy of the abdominal muscles in trained athletes, even when they have a thin layer of subcutaneous fat.

О выборе соотношения доз нейтронов и фотонов при нейтронно-фотонной терапии злокачественных новообразований

Purpose: To evaluate the methodological approaches to the prevention of radiation-induced complications after neutron-photon therapy considering the neutron-photon dose ratio in the tumor. &#x0D; Material and methods: The linear-quadratic model (LQM) and principles of neutron and photon dose distributions in a tissue-equivalent medium were used. Cases with the highest risk of radiation-induced complications (treatment by a single or two opposite fields) were discussed. The number of neutron-photon therapy sessions to ensure a combined total neutron and photon dose was determined where the RBE concept was used. When calculating the total effect (TE) and TDF factor characterizing the damage to the irradiated tissue, the effect of the radiation field size and subcutaneous fat layer on their values was taken into account. &#x0D; Results: Methods for selecting the ratio of the neutron and photon dose contribution to the total dose, providing the maximum permissible radiation dose, were developed. It was established that the dependences of TDF and TE factors and the differences in the values of the allowable number of photon therapy sessions on the depth of the tumor were less pronounced in cases with two opposite radiation fields compared to those with a single field. It can be explained by the fact that with increasing depth, an increase in the entrance dose is compensated by a decrease in the dose contribution formed during irradiation from the opposite field. &#x0D; Conclusion: For neutron-photon therapy using a linear-quadratic model, methodical approaches that might be used to provide an acceptable level of radiation-induced skin reactions for any ratio of neutron-photon doses in a tumor were proposed. The use of these techniques for planning neutron-photon therapy will minimize the risk of radiation-induced complications.

Assessment the Accuracy of Densitometry Measurements Using DMA PP2 Phantom

Purpose of the study — to assess the accuracy of dual energy x-ray absorptiometry (DXA ) for measurements of mineral bone density, bone mineral content, area of selected spine zone of examination as well as impact of subcutaneous fat layer and correction of auto-segmenting of the spine on the mentioned parameters. Material and Methods. The study was performed on iDXA scanner using the designed phantom DMA PP2 of the lumber spine with inlays to simulate subcutaneous fat (SF). To ensure correct assessment of measurements (precision and accuracy) the authors performed fivefold repeated scanning. Two modifications of the phantom were used, with and without SF inlays, as well as two methods for selection of spine range for examination – automatic and correction of autosegmentation. Results. Scanning of the phantom without SF inlays demonstrated a systematic understated values of bone mineral density (BMD) and bone mineral content (BMC) along the full measured interval: mean relative error of BMD for L1-L4 interval was 10.62% with automatic segmentation and 7.43% — with correction of autosegmentation. The least accuracy for BMD and BMC (1.53% and 0.90%, respectively) was observed during SF simulation and with correction of auto-segmentation of the spine. Analysis of variation coefficient for area of examined vertebrae, BMC and BMD demonstrated rather high precision of measurements, namely for BMD without SF in the L1-L4 interval amounted to 1.00% (auto-segmentation) and 0.56% (correction). Variation coefficient for scanning including SF inlays in the interval L1-L4 was 1.00% (auto-segmentation) and 0.68% (correction). Conclusion. The lowest level of accuracy was observed with the SFL object; in this case, the variation coefficient did not exceed 1% for all BMD interval. The mean value of the BMC accuracy also did not exceed 1% with the optimal scan parameters. The study proved the effectiveness of “RSK PK2” phantom when estimating the accuracy of BMD and BMC on iDXA scanner.