Tightening and Reduction of Unwanted Submental Fat Using Triple-Layer High-Intensity Focused Ultrasound: Clinical and 3-Dimensional Imaging Analysis.

BACKGROUND: Unwanted submental fat (SMF) is aesthetically unappealing, but methods of reduction are either invasive or lack evidence of their use. OBJECTIVE: The authors sought to evaluate the safety and efficacy of a novel triple-layer high-intensity focused ultrasound (HIFU) regimen for SMF reduction. METHODS: Forty Korean subjects with moderate/severe SMF were evaluated after receiving a session of triple-layer HIFU treatments (using 3.0-, 4.5-, and 6.0-mm focusing transducers). The objective evaluation based on the 5-point Clinician-Reported Submental Fat Rating Scale (CR-SMFRS) and patients' satisfaction based on the 7-point Subject Self-Rating Scale (SSRS) were determined 8 weeks after treatment. Three-dimensional image analysis was also performed. RESULTS: At the follow-up visit, the proportion of treatment responders defined as subjects with ≥1-point improvement in CR-SMFRS was 62.5%, and the proportion of patients satisfied with appearance of their face and chin (score ≥4 on the SSRS) was 67.5% of the total patients. The results of 3-dimensional analysis were consistent with clinical observations. Only mild and transient side effects were observed for some patients with no serious adverse effects. CONCLUSION: The triple-layer HIFU regimen including the novel 6.0-mm transducer has benefits for tightening and rejuvenation of the area with unwanted SMF, showing reasonable safety profiles.

Histopathologic and Histomorphometric Analysis of Irradiation Injury in Bone and the Surrounding Soft Tissues of the Jaws.

PURPOSE: Surgery of irradiated tissue has an increased complication rate because of the development of hypovascular, hypocellular, and hypoxic tissue. This study was undertaken to perform histopathologic and histomorphometric analyses of irradiation tissue injury in bone and the surrounding soft tissues. MATERIAL AND METHODS: The histopathologic findings of 40 human mandibular bones and the surrounding soft tissue specimens obtained from different patients who underwent surgical procedures for treatment of osteoradionecrosis of the jaws were reviewed. RESULTS: Histopathologic examination showed 7 processes in the following order of appearance: hyperemia, endarteritis, thrombosis, cell loss, hypovascularity, increase of fat in the bone marrow cavity, and fibrosis. Histomorphometric analysis showed significant hypocellularity (P = .007), hypovascularity (P < .001), and fibrosis (P < .001) in irradiated specimens compared with control specimens. CONCLUSION: These results showed that radiation injuries affect the bone and surrounding soft tissues. However, the irradiation-induced injuries, such as cellular loss (hypocellularity) and fibrosis, were more expressive in bone tissue than in the surrounding soft tissues.

The aging neck: a diagnostic approach to surgical and nonsurgical options.

BACKGROUND: The neck is a prominent indicator of aging. Loss of subcutaneous fat, prominence of platysmal banding, jowling along the mandibular border, and excessive skin laxity due to loss of collagen and elastin are common conditions that are treated. Laser technology provides additional benefits when treating the first two anatomical layers of the neck. METHODS: A 7-category classification system of anatomic skin layers of the lower face was developed. Based on the classifications treatments include the use of laser, ultrasonic technology, and toxins. RESULTS: A classification system offering surgical and nonsurgical treatments including a 1440-nm laser fiber with a specifically designed tip to allow targeted energy delivery managed through a thermal sensing device. CONCLUSIONS: Treatment options correlate with the presence and severity of conditions. Categories 1 and 2 have only a fat excess condition. Laser application alone, without skin intervention, is utilized. The amount of fat with subsequent aspiration follows guidelines of categories 2 through 5. The 1440-nm laser helps in all treatments. The surgeon may elect to address skin tightening with surgical tightening in categories 6 and 7. Modalities such as toxins and focused ultrasound can be used to address muscle laxity.

Calculation of water equivalent ratios for various materials at proton energies ranging 10-500 MeV using MCNP, FLUKA, and GEANT4 Monte Carlo codes.

Dosimetry of proton beams is generally evaluated in liquid water, or alternatively in solid phantoms via water equivalent ratios (WER). WER is defined as the ratio of proton range in liquid water to that in a phantom of certain material. Presently, WER is not available in the literature neither for a wide range of energies nor for variety of relevant materials. Thus, the goal of this study is to provide such data through Monte Carlo simulations. WER is calculated for 10-500 MeV energies for compact bone, adipose tissue, polymethyl methacrylate (PMMA), PTFE (teflon), graphite (C), aluminum (Al), copper (Cu), titanium (Ti), and gold (Au) using MCNPX.2.70, GEANT4, and FLUKA Monte Carlo (MC) codes. The MCNPX code was considered as the reference to which other codes were compared. The mean values of WER obtained through the MCNPX simulations for Au, Cu, Ti, Al, PTFE, graphite, PMMA, bone, and adipose tissue were 8.83, 5.40, 3.18, 2.03, 1.87, 1.52, 1.13, 1.71, and 0.96, respectively, for 10-500 MeV energy range. The maximum deviations of WER values between MCNPX and GEANT4 results were about 6.85% for adipose tissue at energies <20 MeV, whereas they were about 7.74%, 7.74% between MCNPX and FLUKA, for adipose and Al, respectively. This inter-code uncertainties are mainly due to different physic models and stopping powers in each code. Comparing the results to that in the literature, the range of discrepancy was found to be 0-8% with greatest discrepancy for Au. Based on the materials evaluated, the PMMA remained the closest to water, for a non-tissue solid material, with an average WER of 1.13, for proton energy ranging 10-500 MeV.

Fast neutron absorbed dose distributions in the energy range 0.5-80 meV--a Monte Carlo study.

Neutron pencil-beam absorbed dose distributions in phantoms of bone, ICRU soft tissue, muscle, adipose and the tissue substitutes water, A-150 (plastic) and PMMA (acrylic) have been calculated using the Monte Carlo code FLUKA in the energy range 0.5 to 80 MeV. For neutrons of energies < or = 20 MeV, the results were compared to those obtained using the Monte Carlo code MCNP4B. Broad-beam depth doses and lateral dose distributions were derived. Broad-beam dose distributions in various materials were compared using two kinds of scaling factor: a depth-scaling factor and a dose-scaling factor. Build-up factors due to scattered neutrons and photons were derived and the appropriate choice of phantom material for determining dose distributions in soft tissue examined. Water was found to be a good substitute for soft tissue even at neutron energies as high as 80 MeV. The relative absorbed doses due to photons ranged from 2% to 15% for neutron energies 10-80 MeV depending on phantom material and depth. For neutron energies below 10 MeV the depth dose distributions derived with MCNP4B and FLUKA differed significantly, the difference being probably due to the use of multigroup transport of low energy (< 19.6 MeV) neutrons in FLUKA. Agreement improved with increasing neutron energies up to 20 MeV. At energies > 20 MeV, MCNP4B fails to describe dose build-up at the phantom interface and penumbra at the edge of the beam because it does not transport secondary charged particles. The penumbra width, defined as the distance between the 80% and 20% iso-dose levels at 5 cm depth and for a 10 x 10 cm2 field, was between 0.9 mm and 7.2 mm for neutron energies 10-80 MeV.

Additional factors for the estimation of mean glandular breast dose using the UK mammography dosimetry protocol.

The UK and European protocols for mammographic dosimetry use conversion factors that relate incident air kerma to the mean glandular dose (MGD) within the breast. The conversion factors currently used were obtained by computer simulation of a model breast with a composition of 50% adipose and 50% glandular tissues by weight (50% glandularity). Relative conversion factors have been calculated which allow the extension of the protocols to breasts of varying glandularity and for a wider range of mammographic x-ray spectra. The data have also been extended to breasts of a compressed thickness of 11 cm. To facilitate the calculation of MGD in patient surveys, typical breast glandularities are tabulated for women in the age ranges 40-49 and 50-64 years, and for breasts in the thickness range 2-11 cm. In addition, tables of equivalent thickness of polymethyl methacrylate have been provided to allow the simulation for dosimetric purposes of typical breasts of various thicknesses.