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Background: Providing correct information about dementia and people living with dementia and improving the attitude toward the disease have important implications in overcoming prejudice and negative perceptions and strengthening the social support system. However, studies are limited about which aspects of dementia knowledge affect attitudes toward it and the influence of such knowledge on particular aspects of such attitudes. Objective: This study examined which part of dementia knowledge affects attitudes toward dementia and, furthermore, the influence of such knowledge on two aspects of attitudes in the general population. Methods: A population-based cross-sectional survey of 1,200 participants aged 20 years or older was adopted. A landline and wireless telephone survey was conducted from October 12 to October 22, 2021. The survey data included self-report questions about dementia knowledge, dementia attitudes, demographics, and family information. Multiple linear regression analysis was performed. Results: Dementia knowledge was positively associated with global dementia attitudes. In terms of the relationship between the two dimensions of dementia attitudes and knowledge, the latter displayed a significant positive association with accepting attitudes (β= 0.121, p

Purpose: The purpose of this study is to provide technical information on commissioning the TrueBeam STx 6 MV flattening-filter free (FFF) beam in the RayStation treatment planning system (TPS) for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) treatments. Methods: For beam modeling, percent depth dose curves, profiles and output factors for jaw-collimated fields and stereotactic cones as well as X-jaws transmission were measured. For multi-leaf collimator (MLC) modeling, MLC model parameters such as offset, gain, curvature, leaf tip width, tongue and groove and transmission were determined and output factors for MLC-collimated fields were measured. Absolute dose calibration was also performed. For beam model and MLC model validation, the American Association of Physicists in Medicine Task Group-119 plans, clinical SRS and SBRT plans and end-to-end testing were performed. Results: Beam characteristics of the 6 MV FFF beam agreed well with those in the literature. Validation results showed that our beam model and MLC model were acceptable for SRS and SBRT treatments. Conclusions: The technical information and dosimetric data provided in this study will be a useful reference for other clinics/institutions which will commission the same machine energy in the RayStation TPS.

Purpose Although notched Collaborative Ocular Melanoma Study (COMS) plaques have been widely used, optic disc dose reduction by notched COMS plaques has not been discussed in the literature. Therefore, this study investigated optic disc dose reduction in ocular brachytherapy using 125I notched COMS plaques in comparison with optic disc dose for 125I standard COMS plaques. Methods For this simulation study, an in‐house brachytherapy dose calculation program was developed using MATLAB software by incorporating the American Association of Physicists in Medicine Task Group‐43 Update (AAPM TG‐43U1) dosimetry formalism with a line source approximation in a homogeneous water medium and COMS seed coordinates in the AAPM TG 129. Using this program, optic disc doses for standard COMS plaques (from 12 to 22 mm in diameter in 2 mm increments) and notched COMS plaques with one seed removed (Case #1, from 12 to 22 mm) and with two seeds removed (Case #2, from 14 to 22 mm) were calculated as a function of tumor margin‐to‐optic disc distance (DT) for various tumor basal dimensions (BDs) for prescription depths from 1 to 10 mm in 1 mm intervals. A dose of 85 Gy for an irradiation time of 168 h was prescribed to each prescription depth. Then absolute and relative optic disc dose reduction by notched COMS plaques (Cases #1 and #2) was calculated for all prescription depths. Results Optic disc dose reduction by notched COMS plaques (Cases #1 and #2) had five unique trends related to maximum optic disc dose reduction and corresponding optimal DT for each BD in each plaque. It increased with increasing prescription depth. Conclusions The results presented in this study would enable the clinician to choose an adequate plaque type among standard and notched 125I COMS plaques and a prescription depth to minimize optic disc dose.

CaO-SiO2-P2O5-B2O3 bioglass (BGS-7) showed highly bioactive properties including osteoconductivity and good mechanical strength, but it has extremely brittle property. In this study, we developed a composite scaffold, which is incorporated into poly(e-caprolactone)(PCL), to overcome the mechanical disadvantage of the bioglass scaffold. The composite scaffolds were fabricated with a microscale porous mesh structure using a 3D melt-printing process. Surface topographical images demonstrated that the bioglass particles were distributed homogeneously throughout the composite scaffolds. The mechanical properties (compression and three-point bending test) of the composite scaffolds showed the toughness of the composite scaffolds was significantly improved compared to that of the pure bioglass scaffold with a similar porosity. We characterized the in vitro biological properties of the pure PCL, BGS-7, and composite scaffolds using MC3T3-E1 cells. As the weight fraction of bioglass increased, the cell proliferation and osteogenic activities significantly increased owing to the enhanced hydrophilic property, protein absorption, and precipitation of calcium phosphate from the bioglass. However, for the high weight fraction of bioglass (60 wt%) in the composite scaffold, the toughness was significantly lower than that of the composite scaffold (40 wt%). Based on these results, the appropriate concentration (40%) of the BGS-7 in the composite showed meaningful bioactivities and toughness.

Mesh brachytherapy is a special type of a permanent brachytherapy implant: it uses low-energy radioactive seeds in an absorbable mesh that is sutured onto the tumor bed immediately after a surgical resection. This treatment offers low additional risk to the patient as the implant procedure is carried out as part of the tumor resection surgery. Mesh brachytherapy utilizes identification of the tumor bed through direct visual evaluation during surgery or medical imaging following surgery through radiographic imaging of radio-opaque markers within the sources located on the tumor bed. Thus, mesh brachytherapy is customizable for individual patients. Mesh brachytherapy is an intraoperative procedure involving mesh implantation and potentially real-time treatment planning while the patient is under general anesthesia. The procedure is multidisciplinary and requires the complex coordination of multiple medical specialties. The preimplant dosimetry calculation can be performed days beforehand or expediently in the operating room with the use of lookup tables. In this report, the guidelines of American Association of Physicists in Medicine (AAPM) are presented on the physics aspects of mesh brachytherapy. It describes the selection of radioactive sources, design and preparation of the mesh, preimplant treatment planning using a Task Group (TG) 43-based lookup table, and postimplant dosimetric evaluation using the TG-43 formalism or advanced algorithms. It introduces quality metrics for the mesh implant and presents an example of a risk analysis based on the AAPM TG-100 report. Recommendations include that the preimplant treatment plan be based upon the TG-43 dose calculation formalism with the point source approximation, and the postimplant dosimetric evaluation be performed by using either the TG-43 approach, or preferably the newer model-based algorithms (viz., TG-186 report) if available to account for effects of material heterogeneities. To comply with the written directive and regulations governing the medical use of radionuclides, this report recommends that the prescription and written directive be based upon the implanted source strength, not target-volume dose coverage. The dose delivered by mesh implants can vary and depends upon multiple factors, such as postsurgery recovery and distortions in the implant shape over time. For the sake of consistency necessary for outcome analysis, prescriptions based on the lookup table (with selection of the intended dose, depth, and treatment area) are recommended, but the use of more advanced techniques that can account for real situations, such as material heterogeneities, implant geometric perturbations, and changes in source orientations, is encouraged in the dosimetric evaluation. The clinical workflow, logistics, and precautions are also presented.

Purpose The purpose of this study is to compare optic disc dose (ODD) between 125I and 103Pd Collaborative Ocular Melanoma Study (COMS) plaques in ocular brachytherapy. Methods A previously validated in-house brachytherapy dose calculation program was used for ODD calculations. ODD was calculated as a function of tumor margin-to-optic disc distance (DT) up to 5 mm for various tumor basal dimensions (BDs), for a prescription depth of 5 mm, and for standard and notched COMS plaques loaded with 125I (model: IAI-125A) and 103Pd (model: IAPd-103A) seeds. ODD calculations were repeated for prescription depths from 2 mm to 10 mm in 1 mm intervals. A prescribed dose of 85 Gy (irradiation time: 120 hours) was normalized to each prescription depth. Dose conversion factors (DCFs) for each prescription depth were calculated by taking a ratio of [total reference air kerma (TRAK) per seed]prescription depth to [TRAK per seed]5 mm. ODD reduction by notched COMS plaques was calculated for each prescription depth by subtracting ODD for notched COMS plaques from ODD for standard COMS plaques. Results Trends of ODD as a function of DT for various BDs are similar between the two seed types in both standard and notched COMS plaques. However, due to the energy difference, there exists a transition distance (dt) for each BD in each plaque at which ODD for 125I COMS plaques equals that for 103Pd COMS plaques. For small BDs, at DT dt, the opposite is observed. For the largest 1-3 BD(s), contrarily, dt occurs within the tumor, and thus, ODD for 125I COMS plaquesis always higher. Trends of ODD reduction by notched COMS plaques as a function of DT for various BDs are the same for the two seed types except that maximum ODD reduction by 103Pd COMS notched plaques is larger. DCF increases with increasing prescription depth for both seed types. Conclusions There exist ODD differences between 125I and 103Pd COMS plaques and the differences depend on DT, BD, plaque size, and prescription depth.

Purpose Although surgical approaches are standard for most non-melanomatous skin cancers, some patients are not candidates due to medical co-morbidities or functional or cosmetic or lesion location. High-dose-rate electronic brachytherapy (HDR-EBT) may be an alternative treatment modality. Material and methods A retrospective chart review was conducted from April 2011 to April 2013. All lesions were pathologically confirmed as malignant basal cell or squamous cell carcinoma. A HDR-EBT system delivered a median biological equivalent dose of 50 Gy total to a depth of 0.1-0.5 cm using various sizes of applicators. Treatment feasibility, acute and late toxicity, cosmetic outcomes, and local recurrence were assessed. Results Thirty-three patients with a mean age of 76 years with 50 cutaneous lesions were treated. Locations included 17 extremity lesions and 33 head and neck lesions. After treatments, acute grade 3 moist desquamation developed in 9 of the lesions (18%). Acute grade 4 ulceration developed in 3 lesions in the lower extremity (6%) and 1 upper lip lesion (2%). These toxicities were improved after a median of 20 days. Amongst the 4 lesions with grade 4 toxicities, a greater proportion were in lower extremity lesions compared to head and neck lesions (75% vs. 25%). There was no difference in the rate of grade 3 and 4 toxicities between patients aged ≤ 75 years and aged > 75 years (p = 0.082). With a mean long-term follow-up of 45.6 months, there was 1 local recurrence treated with surgery and no reported late toxicities. Conclusions Our experience with HDR-EBT for non-melanomatous skin cancers is encouraging in terms of efficacy and convenience for patients. Our long-term follow-up shows a good response in all treated sites. Caution should be used for extremity sites, and more fractionated regimens should be considered to avoid severe acute toxicities.

To establish the relationship among various skin dosimetric indices and different volumetric definitions of skin in high-dose-rate (HDR) balloon breast brachytherapy. Fifty breast cancer patients were treated with HDR balloon brachytherapy. The MammoSite® applicator was used for 40 patients and the Contura® applicator for 10 patients. Skin structure was retrospectively defined by expanding the skin surface internal to the body with a thickness of 1, 2, 3, 4, or 5 mm in one method. In another method, the skin was defined by expanding its external to the body to demonstrate the maximum point dose on the skin surface. For each skin structure defined by six different methods, three dosimetric data points extracted from dose-volume histograms were compared. Dmax was defined as the maximum point dose, and D1cc and D0.1cc were defined as the minimum dose to 1 cm3 and 0.1 cm3 of the most irradiated skin volume, respectively. The relationship among 18 dosimetric parameters was presented in graphs, and linear curve fitting was performed to provide mathematical formulas. For each skin definition, the Dmax, D1cc, and D0.1cc values show a linear relationship such that Dmax is the largest, D0.1cc is the next, and D1cc is the smallest value. For each dosimetric parameter, there was a linear relationship among the dosimetric indices for 6 different skin definitions. For clinical use, all linear relationships were displayed in graphs and two parameters for linear fitting were provided. Average R2 value for curve fitting was 0.978. The presented relationships can be developed in each individual institution and convert one dosimetric index to another for different skin definitions.

The purpose of this study is to compare patient-specific quality assurance (PSQA) results between two dimensional (2D) diode (SRS MapCHECK(®)) and 3D diode (ArcCHECK(®)) arrays. Twenty-eight intracranial stereotactic radiosurgery (SRS) and 26 lung stereotactic body radiation therapy (SBRT) clinical plans with a single lesion were selected and categorized into 4 groups: 20 SRS dynamic conformal arc therapy (DCAT) plans (Group A), 8 SRS volumetric modulated arc therapy (VMAT) plans (Group B), 6 SBRT DCAT plans (Group C) and 20 SBRT VMAT plans (Group D). An individual field of each plan was delivered on SRS MapCHECK and ArcCHECK and QA analysis was performed using 4 gamma criteria of dose difference/distance-to-agreement of 3%/3 mm, 3%/2 mm, 2%/2 mm and 2%/1 mm. Statistical analysis was performed to compare PSQA results between the 2 QA devices. For all 4 groups and all 4 gamma criteria, average gamma passing rates were higher with SRS MapCHECK.

Correction for ‘Mineralized biomimetic collagen/alginate/silica composite scaffolds fabricated by a low-temperature bio-plotting process for hard tissue regeneration: fabrication, characterisation and in vitro cellular activities’ by HyeongJin Lee et al., J. Mater. Chem. B, 2014, 2, 5785–5798, https://doi.org/10.1039/c4tb00931b.

The natural biopolymers, collagen and alginate, have been widely used in various tissue regeneration procedures. However, their low mechanical and osteoinductive properties represent major limitations of their usage as bone tissue regenerative scaffolds. To overcome these deficiencies, biomimetic composite scaffolds were prepared using a mixture of collagen and alginate as a matrix material, and various silica weight fractions as a coating agent. The composite scaffolds were highly porous (porosity > 78%) and consisted of interconnected pores, with a mesh-like structure (strut diameter: 342–389 μm; average pore size: 468–481 μm). After incubation in a simulated body fluid, various levels of bone-like hydroxyapatite (HA) on the surface of the composite scaffolds developed in proportion to the increase in the silica content coating the scaffolds, indicating that the composite scaffolds have osteoinductive properties. The composite scaffolds were characterised in terms of various physical properties (water absorption, biodegradation and mechanical properties, etc.) and biological activities (cell viability, live/dead cells, DAPI/phalloidin analysis, osteogenic gene expression, etc.) using pre-osteoblasts (MC3T3-E1). The mechanical improvement (compressive modulus) of a composite scaffold in compressive mode was ∼2.4-fold in the dry state compared to the collagen/alginate scaffold. Cell proliferation on the composite scaffold was significantly improved by ∼1.3-fold compared to the mineralised collagen/alginate scaffold (control). Osteocalcin levels of the composite scaffold after 28 days in cell culture were significantly enhanced by 3.2-fold compared with the control scaffold. These results suggest that mineralised biomimetic composite scaffolds have potential for use in hard tissue regeneration.

We herein describe a novel hybrid scaffold comprising microsized struts with a core (PCL)–shell (collagen/alginate) structure. The collagen-based hybrid scaffold was fabricated using cryogenic plotting/melt-plotting methods supplemented with a core–shell nozzle. The core region (PCL) in the struts has mechanical support and shape integrity functions, and the shell region (collagen/alginate) enhances biological activities. Through use of various processing conditions, we could manipulate the mechanical properties of the scaffolds without any loss of biological functions, similar to a pure collagen scaffold. The mechanical properties of the hybrid scaffold were enhanced by ∼12-fold compared with those of a pure collagen scaffold due to the reinforcement of the core region (PCL). To demonstrate the feasibility as a hard-tissue scaffold, osteoblast-like cells (MG63) were seeded and the cell-seeding efficiency and various cellular activities were investigated. The cell-seeding efficiency (53%) and cell viability of the hybrid scaffold were similar to those of the pure collagen scaffold (57%), while the pure PCL scaffold showed relatively low cell-seeding efficiency (19%) and viability. To determine its potential as a scaffold for bone tissue regeneration, in vitro cellular activities, including ALP activity and calcium deposition, were compared with those of the pure collagen scaffold; no statistically significant differences compared with those of the pure collagen scaffold were found. These results indicate that the in vitro cellular activities of the hybrid scaffolds were identical to those of the pure collagen scaffold; moreover, the hybrid scaffold exhibited significantly improved mechanical properties.

The surface brachytherapy Task Group report number 253 discusses the common treatment modalities and applicators typically used to treat lesions on the body surface. Details of commissioning and calibration of the applicators and systems are discussed and examples are given for a risk-based analysis approach to the quality assurance measures that are necessary to consider when establishing a surface brachytherapy program.

AimTo create practical lookup tables containing percent depth dose (PDD) and profile parameters of electron beams and to demonstrate clinical application of the lookup tables to skin cancer treatment to ensure target coverage in a clinical setup.Materials and methodsFor 6 and 9 MeV electron energies, PDDs and profiles at clinically relevant depths [i.e., R95 (distal depth of 95% maximum dose), R90, R85 and R80] were measured in water at 100 cm source-to-surface distance for an 10×10 cm2 open field and circular cutouts with diameters of 4, 5, 6, 7 and 8 cm. Then PDD parameters along with profile parameters such as width of isodose lines and penumbra at the clinically relevant depths were determined. Output factors for the cutouts were measured at dmax in water and solid water.ResultsWith PDD and profile parameters, dosimetry lookup tables were generated. Based upon the lookup tables, target coverage at prescribed depths was retrospectively reviewed for three skin cancer cases. The lookup tables suggested larger cutouts for adequate target coverage.FindingsDosimetry lookup tables for electron beam therapy should include profile parameters at clinically relevant depths and be provided to clinicians to ensure target coverage in a clinical setup.

Purpose The aim of the study was to identify potential failure modes (FMs) having a high risk and to improve our current quality management (QM) program in Collaborative Ocular Melanoma Study (COMS) ocular brachytherapy by undertaking a failure modes and effects analysis (FMEA) and a fault tree analysis (FTA). Methods and Materials Process mapping and FMEA were performed for COMS ocular brachytherapy. For all FMs identified in FMEA, risk priority numbers (RPNs) were determined by assigning and multiplying occurrence, severity, and lack of detectability values, each ranging from 1 to 10. FTA was performed for the major process that had the highest ranked FM. Results Twelve major processes, 121 sub-process steps, 188 potential FMs, and 209 possible causes were identified. For 188 FMs, RPN scores ranged from 1.0 to 236.1. The plaque assembly process had the highest ranked FM. The majority of FMs were attributable to human failure (85.6%), and medical physicist–related failures were the most numerous (58.9% of all causes). After FMEA, additional QM methods were included for the top 10 FMs and 6 FMs with severity values > 9.0. As a result, for these 16 FMs and the 5 major processes involved, quality control steps were increased from 8 (50%) to 15 (93.8%), and major processes having quality assurance steps were increased from 2 to 4. Conclusions To reduce high risk in current clinical practice, we proposed QM methods. They mainly include a check or verification of procedures/steps and the use of checklists for both ophthalmology and radiation oncology staff, and intraoperative ultrasound-guided plaque positioning for ophthalmology staff.

Purpose To investigate Axxent (iCAD, Inc., San Jose, CA) electronic brachytherapy balloon deformation and its dosimetric impact because of an external flexible shield (FlexiShield [FS]; iCAD, Inc.). Methods and Materials Prostheses breast tissue phantom overlaid three spherical balloon applicators to simulate three clinical scenarios depending on minimum skin-to-balloon surface spacing (SS): balloon with SS of 2 cm, 1 cm, and balloon with 1 cm SS and touching the chest wall. Two sets of megavoltage CT (MVCT) scans were obtained with or without FS for 15 different sizes of balloons. For 45 pairs of MVCT scans, balloon deformation was measured in superior–inferior (d SI ) dimension on coronal and sagittal planes and anterior–posterior (d AP ) and lateral (d LAT ) dimensions on the equatorial plane of balloon. SS was also compared. A treatment plan was made on each MVCT scan. Doses at four balloon surface points and skin were compared. Conformity index value was also compared to evaluate three-dimensional dose distribution. Clinically, 20 Gy was prescribed to the surface of balloon. Results Balloon deformation was observed with compression in SI and AP dimensions and expansion in lateral dimension. Average SI compression was 0.5 mm. Average d Lat - d AP was 2.4 mm, which resulted in elevated point doses at AP dimension by 10.8% of prescribed dose and reduced point doses at lateral dimension by 4.6%. FS decreased SS by 1.8 mm, increasing skin dose by 1.2 Gy, on average. Conformity index value was decreased from 0.922 to 0.908, on average. Conclusions This phantom study demonstrates that use of skin shielding during breast intraoperative radiation therapy can cause balloon deformation and SS reduction, resulting in dosimetric changes that are disregarded in current practice.

Background: Notched plaques were devised to reduce radiation dose to the optic disc in ocular brachytherapy. Although notched plaques have been widely used in clinic, optic disc dose reduction by the use of notched plaques has not been discussed in the literature. Therefore, this study investigated optic disc dose reduction in ocular brachytherapy using 125I notched Collaborative Ocular Melanoma Study (COMS) plaques based on our institutional practice. Methods: Using our in-house brachytherapy dose calculation program in which the American Association of Physicists in Medicine Task Group-43 Update (AAPM TG-43U1) dosimetry formalism with a line source approximation in a homogeneous water medium and COMS seed coordinates in the AAPM TG 129 were incorporated, optic disc doses for standard COMS plaques (from 12 mm to 22 mm in diameter in 2 mm increments) and notched COMS plaques with one seed removed (Case #1, from 12 mm to 22 mm in diameter in 2 mm increments) and two seeds removed (Case #2, from 14 mm to 22 mm in diameter) were calculated as a function of tumor margin-to-optic disc distance (DT) for various tumor basal dimensions (BDs) for prescription depths from 1 mm to 10 mm in 1 mm intervals. A prescribed dose was 85 Gy for an irradiation time of 168 hours to each prescription depth. Absolute and relative optic disc dose reduction by notched COMS plaques (Cases #1 and #2) for all prescription depths was calculated from optic disc dose differences between standard and notched COMS plaques. Results: Optic disc dose reduction by notched COMS plaques (Cases #1 and #2) had five unique trends which are related to maximum optic disc dose reduction and corresponding optimal DT for each BD in each plaque. Optic disc dose reduction increased with increasing prescription depth. Conclusions: The results presented in this study (magnitude of optic disc dose reduction and its trends) would enable the clinicians (both ophthalmologist and radiation oncologist) to choose an adequate plaque type among standard 125I COMS plaques and notched 125I COMS plaques (Cases #1 and #2) and a prescription depth to minimize optic disc dose for a given clinical case.

Bioprinting is an emerging technology for producing tissue-mimetic 3-D structures using cell-containing hydrogels (bioink). Various synthetic and natural hydrogels with key characteristics, including biocompatibility, biodegradability, printability and crosslinkability, have been employed as ink materials in bioprinting. Choosing the right cell-containing “bioink” material is the most essential step for fabricating 3-D constructs with a controlled mechanical and biochemical microenvironment that can lead to successful tissue regeneration and repair. Here, we demonstrate that the genetically engineered M13 phage holds great potential for use as a versatile nanoink for printing 3-D cell-laden matrices. In particular, M13 phages displaying integrin-binding (GRGDS) and calcium-binding (DDYD) domains on their surface were blended with alginate to successfully form Ca2+-crosslinked hydrogels. Furthermore, 3-D cell-laden scaffolds with high cell viability were generated after optimizing the printing process. The MC3T3-E1 cells within these scaffolds showed enhanced proliferation and differentiation rates that increased proportionally with the concentration of phages in the 3-D matrices compared with the rates of cells in pure alginate scaffolds. Statement of significance Bioprinting is an emerging technology for producing tissue-mimetic 3-D structures using cell-containing hydrogels called bioink. Choosing the right bioink is essential for fabricating 3-D structures with controlled mechanical and biochemical properties which lead to successful tissue regeneration. Therefore, there is a growing demand for a new bioink material that can be designed from molecular level. Here, we demonstrate that genetically engineered M13 phage holds great potential for use as versatile bioink. The phage-based bioink benefits from its replicability, self-assembling property, and tunable molecular design and enables bioprinted scaffolds to exhibit improved cell viability, proliferation and differentiation. This study opens the door for the development of genetically tunable nanofibrous bioink materials which closely mimic natural structural proteins in the extracellular matrix.

To report an institutional experience with episcleral plaque brachytherapy for medium-sized uveal melanoma. Variations in prescription dose point and dose rate were compared with Collaborative Ocular Melanoma Study (COMS) Group.A retrospective review was performed for 116 patients treated with iodine-125 plaque brachytherapy. About 85 Gy was prescribed to either the tumor apex (108 patients) or at 5 mm (8 patients) with dose rate ranging from 50.6 to 98.2 cGy/h. Patients were followed up for local tumor control, eye preservation, and vision retention. Dose and dose rate to tumor and sensitive structures were calculated. Multivariate and univariate analyses were performed to investigate correlation between clinical outcomes and dose/dose rate variables.Patients in this study were slightly older with worse visual acuity at baseline, but tumor size and position and ratio of ciliary body involvement were comparable to COMS population. Outcomes data were comparable to COMS: 95.3% local tumor control at 5 years and 77.7% vision preservation at 3 years. Only 4 patients needed enucleation because of tumor growth. Significant correlation was found between enucleation and tumor height and maximal scleral dose/dose rate as well as vision retention and tumor height and macula dose/dose rate.For tumors with5 mm height, prescribing to tumor apex enabled to decrease dose to all sensitive structures without any loss of local control. Although dose rate was lowered to 50.6 cGy/h from the American Brachytherapy Society guidelines (60-105 cGy/h) because of limited availability of operating room (i.e., weekly), there was no difference in either local tumor control or complications.

Herein, poly(ɛ-caprolactone) (PCL) surfaces were treated to form various roughness values ( R a = 290–445 nm) and polar functional groups on the surfaces using a plasma-etching process, followed by immersion into simulated body fluid (SBF) for apatite formation. The surface morphology, chemical composition, and mean roughness of the plasma-etched PCL surfaces were measured, and various physical and morphological properties (water contact angles, protein absorption ability, and crystallite size of the apatite layer) of the in vitro mineralized PCL surfaces were evaluated. The roughened PCL surface P-3, which was treated with a sufficient plasma exposure time (4 h), achieved homogeneously distributed apatite formation after soaking in SBF for 7 days, as compared with other surfaces that were untreated or plasma-treated for 30 min or 2 h. Furthermore, to demonstrate their feasibility as a biomimetic surface, pre-osteoblast cells (MC3T3-E1) were cultured on the mineralized PCL surfaces, and cell viability, DAPI-phalloidin fluorescence assay, and alizarin red-staining of the P-3 surface were highly improved compared to the P-1 surface treated with a 30-min plasma exposure time; compared to untreated mineralized PCL surface (N-P), P-3 showed even greater improvements in cell viability and DAPI-phalloidin fluorescence assay. Based on these results, we found that the mineralized PCL surface supplemented with the appropriate plasma treatment can be implicitly helpful to achieve rapid hard tissue regeneration.

The objective of this work is to evaluate dosimetric impact of multilumen balloon applicator rotation in high‐dose‐rate (HDR) brachytherapy for breast cancer. Highly asymmetrical dose distribution was generated for patients A and B, depending upon applicator proximity to skin and rib. Both skin and rib spacing was ≤0.7 cm for A; only rib spacing was ≤0.7 cm for B. Thirty‐five rotation scenarios were simulated for each patient by rotating outer lumens every 10° over ±180∘ range with respect to central lumen using mathematically calculated rotational matrix. Thirty‐five rotated plans were compared with three plans: 1) original multidwell multilumen (MDML) plan, 2) multidwell single‐lumen (MDSL) plan, and 3) singledwell single‐lumen (SDSL) plan. For plan comparison, planning target volume for evaluation (PTV_EVAL) coverage (dose to 95% and 90% volume of PTV_EVAL) (D95 and D90), skin and rib maximal dose (Dmax), and normal breast tissue volume receiving 150% (V150) and 200% (V200) of prescribed dose (PD) were evaluated. Dose variation due to device rotation ranged from −5.6% to 0.8% (A) and −6.5% to 0.2% (B) for PTV_EVAL D95; −5.2% to 0.4% (A) and −4.1% to 0.7% (B) for PTV_EVAL D90; −2.0 to 18.4% (A) and −7.8 to 17.5% (B) for skin Dmax; −11.1 to 22.8% (A) and −4.7 to 55.1% (B) of PD for rib Dmax, respectively. Normal breast tissue V150 and V200 variation was

In recent years, a variety of biomimetic hydrogel scaffolds have been used in tissue engineering because hydrogels can provide reasonable soft-tissue-like environmental conditions for various cell responses. However, although hydrogels can provide an outstanding biofunctional platform, their poor mechanical stability and low processability have been obstacles for their usage as biomedical scaffolds. To overcome this limitation, we propose a simple and versatile method using 3D printing supplemented with a low-temperature working plate and coating process to reinforce the mechanical properties and various cellular activities by accommodating the poly(e-caprolactone) (PCL). To determine the efficiency of the method, we used two typical hydrogels (alginate and collagen), which were deposited in a multi-layer configuration, and PCL as a coating agent. The scaffolds were evaluated in terms of various physical and cellular activities (metabolic activity and osteogenic activity). Throughout the experiments, significant increases in the tensile modulus (>6-fold), cell proliferation (>1.2-fold), and calcium deposition (>1.3-fold) were observed for the hydrogel/PCL scaffolds compared to those for pure hydrogel. Based on the experimental results, we can confirm that the proposed hydrogel scaffold can be a highly promising biomedical scaffold for application in tissue regeneration.

PURPOSE: To retrospectively report pacemaker (PM)/implantable cardioverteredefibrillator (ICD) dose in balloon high-dose-rate (HDR) brachytherapy and provide distanceedose graph and table to approximately estimate the maximal device dose. METHODS AND MATERIALS: For 3 patients (A, B, and C), PM/ICD was retrospectively contoured on planning computed tomography images and its maximal dose was extracted from a doseevolume histogram. The surface of 1 cm expansion from balloon was prescribed to 34 Gy and the inverse square law was dominant factor in dose calculation. Therefore, the maximal PM/ICD dose was approximately estimated from the distanceedose graph or table and compared with that of the treatment plan. RESULTS: The minimal deviceeballoon surface distance was 10.9, 18.4, and 4.3 cm for patient A, B, and C, respectively. The maximal dose estimated from the proposed table/graph was 2.1 vs. 1.61 Gy for patient A, 0.87 vs. 0.49 Gy for patient B, and 8.9 vs. 9.14 Gy for patient C compared with that from the treatment plan. CONCLUSIONS: Depending on the location of PM/ICD relative to the tumor bed, balloon HDR brachytherapy is feasible if the maximal dose is less than or equal to the dose limit. The proposed distanceedose graph and/or table enable to approximately predict the maximal device dose based on the measurement of minimal distance between lumpectomy and the device before balloon implantation for the suitability of balloon HDR brachytherapy. 2012 American Brachytherapy

Recent studies with two fractionation schemes predicted that the volume of chest wall receiving30 Gy (V30) correlated with chest wall pain after stereotactic body radiation therapy (SBRT) to the lung. This study developed a predictive model of chest wall pain incorporating radiobiologic effects, using clinical data from four distinct SBRT fractionation schemes.102 SBRT patients were treated with four different fractionations: 60 Gy in three fractions, 50 Gy in five fractions, 48 Gy in four fractions, and 50 Gy in 10 fractions. To account for radiobiologic effects, a modified equivalent uniform dose (mEUD) model calculated the dose to the chest wall with volume weighting. For comparison, V30 and maximum point dose were also reported. Using univariable logistic regression, the association of radiation dose and clinical variables with chest wall pain was assessed by uncertainty coefficient (U) and C statistic (C) of receiver operator curve. The significant associations from the univariable model were verified with a multivariable model.106 lesions in 102 patients with a mean age of 72 were included, with a mean of 25.5 (range, 12-55) months of follow-up. Twenty patients reported chest wall pain at a mean time of 8.1 (95% confidence interval, 6.3-9.8) months after treatment. The mEUD models, V30, and maximum point dose were significant predictors of chest wall pain (p0.0005). mEUD improved prediction of chest wall pain compared with V30 (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.11). The mEUD with moderate weighting (a = 5) better predicted chest wall pain than did mEUD without weighting (a = 1) (C = 0.79 vs. 0.77 and U = 0.16 vs. 0.14). Body mass index (BMI) was significantly associated with chest wall pain (p = 0.008). On multivariable analysis, mEUD and BMI remained significant predictors of chest wall pain (p = 0.0003 and 0.03, respectively).mEUD with moderate weighting better predicted chest wall pain than did V30, indicating that a small chest wall volume receiving a high radiation dose is responsible for chest wall pain. Independently of dose to the chest wall, BMI also correlated with chest wall pain.

Purpose: To investigate radiation dose to the heart in 60 patients with left-sided breast cancer who were treated with balloon-based high-dose-rate brachytherapy using MammoSite or Contura applicators. Methods and Materials: We studied 60 consecutive women with breast cancer who were treated with 34 Gy in 10 twice-daily fractions using MammoSite (n = 37) or Contura (n = 23) applicators. The whole heart and the left and right ventricles were retrospectively delineated, and dose–volume histograms were analyzed. Multiple dosimetrics were reported, such as mean dose (Dmean); relative volume receiving 1.7, 5, 10, and 20 Gy (V1.7, V5, V10, and V20, respectively); dose to 1 cc (D1cc); and maximum point dose (Dmax). Biologic metrics, biologically effective dose and generalized equivalent uniform dose were computed. The impact of lumpectomy cavity location on cardiac dose was investigated. Results: The average ± standard deviation of Dmean was 2.45 ± 0.94 Gy (range, 0.56–4.68) and 3.29 ± 1.28 Gy (range, 0.77–6.35) for the heart and the ventricles, respectively. The average whole heart V5 and V10 values were 10.2% and 1.3%, respectively, and the heart Dmax was >20 Gy in 7 of 60 (11.7%) patients and >25 Gy in 3 of 60 (5%) patients. No cardiac tissue received $30 Gy. The V1.7, V5, V10, V20, and Dmean values were all higher for the ventricles than for the whole heart. For balloons located in the upper inner quadrant of the breast, the average whole heart Dmean was highest. The Dmean, biologically effective dose, and generalized equivalent uniform dose values for heart and ventricles decreased with increasing minimal distance from the surface of the balloon. Conclusions: On the basis of these comprehensive cardiac dosimetric data, we recommend that cardiac dose be routinely reported and kept as low as possible in balloon-based high-dose-rate brachytherapy treatment planning for patients with left-sided breast cancer so the correlation with future cardiac toxicity data can be investigated. 2012 Elsevier Inc. Cardiac dose, Heart, High-dose-rate brachytherapy, Balloon, MammoSite, Contura.

PurposeThere has been significant interest in the classification of exchange rate regimes in order to investigate a wide range of hypotheses. Studies of the effects of exchange rate regimes on crises and other aspects of economic performance can have important implications for policy choices. The paper provides a guide to the major new large data sets that classify exchange rate regimes and to critically analyze important methodological issues.Design/methodology/approachThe study surveys and critiques the literature and provides theoretical analysis of major issues involved in classifying exchange rate regimes.FindingsThe study finds that all of the new data sets have problems but some have more problems than others and several of them are substantial improvements on what was previously available. It is also shown that the best ways to classify depend on the issue being addressed and that for detailed studies variants of measures using the concept of exchange market pressure are the most promising. Directions for future research are also discussed.Originality/valueThe paper makes researchers aware of the new data sets that are available and discusses their strengths and weaknesses. It also presents original analysis of several of the major conceptual issues involved in classifying exchange rate regimes.

The objective of this study was to evaluate the safety, toxicity, and planning concerns involved in accelerated partial breast irradiation (APBI) for patients with breast cancer who have a pacemaker or an automatic implantable cardioverter-defibrillator (AICD) and who desire breast conservation.We performed a review of prospectively obtained data for patients with early-stage breast cancer with a pacemaker or AICD treated between April 2007 and July 2010. Patients were treated with either 3D conformal external beam irradiation (3D-CRT) or high-dose rate balloon brachytherapy (HDRBB) as performed in the National Surgical Adjuvant Breast and Nowel Project (NSABP) B-39/Radiation Therapy Oncology Group (RTOG) 0413 protocol. Device interrogation was performed after the first and last radiation treatment, with comparative cardiac monitoring performed before and after the first three treatments.Eight patients were treated and have a mean follow-up of 6 months. Three patients received HDRBB delivering 34 Gy in 10 fractions. Mean planning target volume for evaluation (PTV_EVAL) coverage was 93.6%. The maximum radiation dose delivered to any device was 1.03 Gy, with a mean pacemaker distance to lumpectomy cavity (DLC) of 9.1 cm. Five patients received 3D-CRT consisting of 38.5 Gy in 10 fractions. The mean 90% PTV_EVAL coverage was 97.3%. Maximum dose delivered to any device was 1.68 Gy at a DLC of 9 cm. Local toxicity did not exceed grade 1, and no adverse device events were noted.APBI in patients with pacemakers or AICDs who desire breast preservation seems to be a technically safe and reasonable application of targeted radiation therapy.

Purpose: An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. Methods: The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skinsurface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography(CT)images. Therefore, the maximal dose to this volume occurs on the skinsurface the same with a conventional manual selection method. The rib was also delineated in the planning CTimages and its maximal dose was extracted from its DVH. The absolute ( Abdiff = | D max Man − D max DVH | ) and relative ( Rediff [ % ] = 100 × ( | D max Man − D max DVH | ) / D max DVH ) maximal skin and rib dose differences between the manual selection method ( D max Man ) and the objective method ( D max DVH ) were measured for 50 balloon-based HDR (25 MammoSite® and 25 Contura®) patients. Results: The average ± standard deviation of maximal dose difference was 1.67 % ± 1.69 % of the prescribed dose (PD). No statistical difference was observed between MammoSite® and Contura® patients for both Abdiff and Rediff[%] values. However, a statistically significant difference ( p value 0.0001 ) was observed in maximal rib dose difference compared with maximal skindose difference for both Abdiff ( 2.30 % ± 1.71 % vs 1.05 % ± 1.43 % ) and Rediff[%] ( 2.32 % ± 1.79 % vs 1.21 % ± 1.41 % ). In general, rib has a more irregular contour and it is more proximally located to the balloon for 50 HDR patients. Due to the inverse square law factor, more dose difference was observed in higher dose range ( D max > 90 % ) compared with lower dose range ( D max 90 % ) : 2.16 % ± 1.93 % vs 1.19 % ± 1.25 % with p value of 0.0049. However, the Rediff[%] analysis eliminated the inverse square factor and there was no statistically significant difference ( p value = 0.8931 ) between high and low dose ranges. Conclusions: The objective method using volumetric information of skin and rib can determine the planner-independent maximal dose compared with the manual selection method. However, the difference was 2 % of PD, on average, if appropriate attention is paid to selecting a manual dose point in 3D planning CTimages.

The objective of this work is to evaluate the interfractional biological effective dose (BED) variation in MammoSite high dose rate (HDR) brachytherapy. Dose distributions of 19 patients who received 34 Gy in 10 fractions were evaluated. A method was employed to account for nonuniform dose distribution in the BED calculation. Furthermore, a range of α/β values was utilized for specific clinical end points: fibrosis, telangiectasia, erythema, desquamation and breast carcinoma. Two scenarios were simulated to calculate the BED value using: i) the same dose distribution of fraction 1 over fractions 2–10 (constant case, CC), and ii) the actual delivered dose distribution for each fraction 1–10 (interfraction dose variation case, IVC). Although the average BED difference (IVC – CC) was

Purpose To examine the feasibility of using the MammoSite brachytherapy applicator in the retreatment of the previously irradiated breast. Methods and materials Between March 2004 and March 2007, three patients previously treated with external beam radiotherapy were retreated using the MammoSite brachytherapy device. Two patients were treated for an ipsilateral breast tumor recurrence after breast conservation surgery and postoperative irradiation, whereas the third patient developed an in-field breast cancer likely associated with Hodgkin's disease mantle irradiation 27 years before. The recurrent histology of two was ductal carcinoma in situ ([DCIS] one originally presenting as infiltrating ductal carcinoma [IDC] and the other as DCIS), whereas the Hodgkin's disease patient presented with IDC. All patients received a twice-daily tumor dose of 3400 cGy at 340 cGy/fraction. The mean maximum skin dose was 53.4% (range, 49.5–60.3%) of the prescribed dose. Results With a mean followup of 32 months, no patient developed a local recurrence. Cosmesis in all three cases as graded by the National Surgical Adjuvant Breast and Bowel Project, cosmesis criteria was excellent (Grade I) in all cases. Dosimetric calculations demonstrated that the device allows for appropriate local irradiation while sparing the previously irradiated skin of the involved breast as defined by the protocol standard. Conclusions Use of the MammoSite device in the treatment of the previously irradiated breast is feasible and may provide adequate local control as well as acceptable cosmesis in carefully selected patients.

To establish an inverse planning set of parameters (class solution) to boost dominant intra-prostatic lesion (DIL) defined by MRI/MRSI.For 15 patients, DIL were contoured on CT or MR images and a class solution was developed to boost the DIL under the dosimetric requirements of the RTOG-0321 protocol. To determine the maximum attainable level of boost for each patient, 5 different levels were considered, at least 110%, 120%, 130%, 140% and 150% of the prescribed dose. The maximum attainable level was compared to the plan without boost using cumulative dose volume histogram (DVH).DIL dose escalation was feasible for 11/15 patients under the requirements. The planning target volume (PTV) dose was slightly increased, while the DIL dose was significantly increased without any violation of requirements. With slight adjustments of the dose constraint parameters, the dose escalation was feasible for 13/15 patients under requirements.Using a class solution, a dose escalation of the MRI/MRSI defined DIL up to 150% while complying with RTOG dosimetric requirements is feasible. This HDR brachytherapy approach to dose escalation allows a significant dose increase to the tumor while maintaining an acceptable risk of complications.

Purpose To measure the interfraction changes of the MammoSite applicator and evaluate their dosimetric effect on target coverage and sparing of organs at risk. Methods and Materials A retrospective evaluation of the data from 19 patients who received 10 fractions (34 Gy) of high-dose-rate partial breast irradiation was performed. A computed tomography-based treatment plan was generated for Fraction 1, and a computed tomography scan was acquired just before the delivery of each fraction to ensure a consistent shape of the balloon. The eccentricity, asymmetry, and planning target volume (PTV) for plan evaluation purposes (PTV_EVAL), as well as trapped air gaps, were measured for all patients. Furthermore, 169 computed tomography-based treatment plans were retrospectively generated for Fractions 2–10. Interfraction dosimetric variations were evaluated using the %PTV_EVAL coverage, target dose homogeneity index, target dose conformal index, and maximum doses to the organs at risks. Results The average variation of eccentricity and asymmetry from Fraction 1 values of 3.5% and 1.1 mm was −0.4% ± 1.6% and −0.1 ± 0.6 mm. The average trapped air gap volume was dramatically reduced from before treatment (3.7 cm 3 ) to Fraction 1 (0.8 cm 3 ). The PTV_EVAL volume change was insignificant. The average variation for the %PTV_EVAL, target dose homogeneity, and target dose conformal index from Fraction 1 values of 94.7%, 0.64, and 0.85 was 0.15% ± 2.4%, −0.35 ± 2.4%, and −0.34 ± 4.9%, respectively. The average Fraction 1 maximum skin and ipsilateral lung dose of 3.2 Gy and 2.0 Gy varied by 0.08 ± 0.47 and −0.16 ± 0.29 Gy, respectively. Conclusion The interfraction variations were patient specific and fraction dependent. Although the average interfraction dose variations for the target and organs at risk were not clinically significant, the maximum variations could be clinically significant.

A dosimetric comparison was performed on external-beam three-dimensional conformal partial breast irradiation (PBI) and whole breast irradiation (WBI) plans for patients enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-39/Radiation Therapy Oncology Group (RTOG) 0413 protocol at our institution. Twenty-four consecutive patients were treated with either PBI (12 patients) or WBI (12 patients). In the PBI arm, the lumpectomy cavity was treated to a total dose of 38.5 Gy at 3.85 Gy per fraction twice daily using a four-field noncoplanar beam setup. A minimum 6 h interval was required between fractions. In the WBI arm, the whole breast including the entirety of the lumpectomy cavity was treated to a total dose of 50.4 Gy at 1.8 Gy per fraction daily using opposed tangential beams. The lumpectomy cavity volume, planning target volume for evaluation (PTV_EVAL), and critical structure volumes were contoured for both the PBI and WBI patients. Dosimetric parameters, dose volume histograms (DVHs), and generalized equivalent uniform dose (gEUD) for target and critical structures were compared. Dosimetric results show the PBI plans, compared to the WBI plans, have smaller hot spots in the PTV_EVAL (maximum dose: 104.2 % versus 110.9 % ) and reduced dose to the ipsilateral breast ( V 50 : 48.6 % versus 92.1 % and V 100 : 10.2 % versus 50.5 % ), contralateral breast ( V 3 : 0.16 % versus 2.04 % ), ipsilateral lung ( V 30 : 5.8 % versus 12.7 % ), and thyroid (maximum dose: 0.5 % versus 2.0 % ) with p values ≤ 0.01 . However, similar dose coverage of the PTV_EVAL ( 98 % for PBI and 99 % for WBI, on average) was observed and the dose difference for other critical structures was clinically insignificant in both arms. The gEUD data analysis showed the reduction of dose to the ipsilateral breast and lung, contralateral breast and thyroid. In addition, preliminary dermatologic adverse event assessment data suggested reduced skin toxicity for patients treated with the PBI technique.

The aim of this study is to investigate the feasibility of using conventional jaws to deliver inverse planned intensity-modulated radiotherapy (IMRT) plans for patients with prostate cancer. For ten patients, each had one three-dimensional conformal plan (3D plan) and seven inverse IMRT plans using direct aperture optimization. For IMRT plans using conventional jaws (JO plans), the number of apertures per beam angle was set from two to seven while three apertures per beam angle were set for the multi-leaf collimator (MLC) plans. To evaluate each planning method, we compared average dose volume histograms (DVH), the conformal index (COIN), total number of segments and total number of monitor units. Among the JO plans with the number of apertures per beam angle varying from two to seven, no difference was observed in the average DVHs, and the plan conformal index became saturated after four apertures per beam angle. Subsequently, JO plans with four apertures per beam angle (JO-4A) were compared with 3D and MLC plans. Based on the average DVHs, no difference was found among 3D, JO-4A and MLC plans with regard to the planning target volume and rectum, but the DVHs for the bladder and penile bulb were significantly better with inverse IMRT plans than those with 3D plans. When compared with the plan conformity, the average COIN values for 3D, JO-4A and MLC plans were 0.61 +/- 0.07, 0.73 +/- 0.05 and 0.83 +/- 0.05, respectively. In conclusion, inverse IMRT plans using conventional jaws are clinically feasible, achieving better plan quality than 3D-CRT plans.

Purpose Electronic brachytherapy (eBT) has gained acceptance over the past 5 years for the treatment of non-melanomatous skin cancer (NMSC). Although the prescription depth and radial margins can be chosen using clinical judgment based on visual and biopsy-derived information, we sought a more objective modality of measurement for eBT planning by using ultrasound (US) to measure superficial (< 5 mm depth) lesions. Material and methods From December 2013 to April 2015, 19 patients with 23 pathologically proven NMSCs underwent a clinical examination and US evaluation of the lesions prior to initiating a course of eBT. Twenty lesions were basal cell carcinoma and 3 lesions were squamous cell carcinoma. The most common location was the nose (10 lesions). A 14 or 18 MHz US unit was used by an experienced radiologist to determine depth and lateral extension of lesions. The US-measured depth was then used to define prescription depth for eBT planning without an added margin. A margin of 7 mm was added radially to the US lateral extent measurements, and an appropriate cone applicator size was chosen to cover the target volume. Results The mean depth of the lesions was 2.1 mm with a range of 1-3.4 mm, and the mean largest diameter of the lesions was 8 mm with a range of 2.6-20 mm. Dose ranged from 32-50 Gy in 8-20 fractions with a median dose of 40 Gy in 10 fractions. All patients had a complete response and no failures have occurred with a median follow-up of 12 months (range of 6-22 months). Also, no prolonged skin toxicities have occurred. Conclusions A routinely available radiological US unit can objectively determine depth and lateral extension of NMSC lesions for more accurate eBT treatment planning, and should be considered in future eBT treatment guidelines.

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) have been shown to be very useful for identifying prostate cancers. For high sensitivity, the MRI/MRSI examination is often acquired with an endorectal probe that may cause a substantial deformation of the prostate and surrounding soft tissues. Such a probe is removed prior to radiation therapy treatment. To register diagnostic probe-in magnetic resonance (MR) images to therapeutic probe-out MR images for treatment planning, a new deformable image registration method is developed based on biomechanical modeling of soft tissues and estimation of uncertain tissue parameters using nonlinear optimization. Given two-dimensional (2-D) segmented probe-in and probe-out images, a finite element method (FEM) is used to estimate the deformation of the prostate and surrounding tissues due to displacements and forces resulting from the endorectal probe. Since FEM requires tissue stiffness properties and external force values as input, the method estimates uncertain parameters using nonlinear local optimization. The registration method is evaluated using images from five balloon and five rigid endorectal probe patient cases. It requires on average 37 s of computation time on a 1.6 GHz Pentium-M PC. Comparing the prostate outline in deformed probe-out images to corresponding probe-in images, the method obtains a mean Dice Similarity Coefficient (DSC) of 97.5% for the balloon probe cases and 98.1% for the rigid probe cases. The method improves significantly over previous methods (P < 0.05) with greater improvement for balloon probe cases with larger tissue deformations.

C l i n M e d International Library Citation: Kim Y (2014) Isn’t it the Timing for Physics Guidelines on High Dose Rate (HDR) Brachytherapy for Localized Prostate Cancer?. Int J Cancer Clin Res 1:002e Received: August 15, 2014: Accepted: August 21, 2014: Published: August 23, 2014 Copyright: © 2014 Kim Y. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Kim, Int J Cancer Clin Res 2014, 1:1

Endorectal coils (ERCs) are used for acquiring high spatial resolution magnetic resonance (MR) images of the human prostate. The goal of this study is to determine the impact of an expandable versus a rigid ERC on changes in the location and deformation of the prostate gland and subsequently on registering prostate images acquired with and without an ERC. Sagittal and axial T2 weighted MR images were acquired from 25 patients receiving a combined MR imaging/MR spectroscopic imaging staging exam for prostate cancer. Within the same exam, images were acquired using an external pelvic phased array coil both alone and in combination with either an expandable ERC (MedRad, Pittsburgh, PA) or a rigid ERC (USA Instruments, Aurora, OH). Rotations, translations and deformations caused by the ERC were measured and compared. The ability to register images acquired with and without the ERC using a manual rigid-body registration was assessed using a similarity index (SI). Both ERCs caused the prostate to tilt anteriorly with an average tilt of 18.5 degrees (17.4 +/- 9.9 and 19.5 +/- 11.3 degrees, mean +/- standard deviation, for expandable and rigid ERC, respectively). However, the expandable coil caused a significantly larger distortion of the prostate as compared to the rigid coil; compressing the prostate in the anterior/posterior direction by 4.1 +/- 3.0 mm vs 1.2 +/- 2.2 mm (14.5% vs 4.8%) (p < 0.0001), and widening the prostate in the right/left direction by 3.8 +/- 3.7 mm vs 1.5 +/- 3.1 mm (8.3% vs 3.4%) (p = 0.004). Additionally, the ability to manually align prostate images acquired with and without ERC was significantly (p < 0.0001) better for the rigid coil (SI = 0.941 +/- 0.008 vs 0.899 +/- 0.033, for the rigid and expandable coils, respectively). In conclusion, the manual rigid-body alignment of prostate MR images acquired with and without the ERC can be improved through the use of a rigid ERC.

Purpose To dose escalate selected regions inside the prostate without compromising the dose coverage of the prostate and the protection to the urethra, rectum, and bladder for prostate cancer patients treated with high-dose-rate brachytherapy. Methods and materials Magnetic resonance imaging combined with magnetic resonance spectroscopy imaging was used to differentiate between normal and malignant prostate and define cancer-validated dominant intraprostatic lesions (DIL) on 10 patients. The DILs were then contoured on the planning scans (CT or MRI based, 5 patients each), and our inverse planning dose optimization algorithm (called IPSA) was used to generate dose distributions for 3 different boost levels. Dose–volume histograms of the target and each organ at risk were compared with optimized plans without DIL boost. Results Combined MRI/magnetic resonance spectroscopic imaging identified 2 DILs in 8/10 of the 10 patients studied and a single DIL in the remaining 2 patients. The average prostate dose coverage V100 was 97% (σ = 1.0%). When the minimum DIL dose requested was 120% of the prescribed dose, the average DIL V120 was 97.1% (σ = 1.8%). For a boost value of 150%, the average V150 ranged from 77.8% to 86.1%, depending on the upper limit of the dose constraints. The bladder V50 increased by 1%, independently of the boost levels. The absolute increases in V50 for the rectum varied from 1% to 3%, depending on the boost level. The urethra V120 were increased by 13.4% and 32.5% for the lowest and highest boost levels, respectively. Conclusion The DIL dose can be escalated to a minimum of 120% while the entire prostate is treated simultaneously, without increasing the dose to surrounding normal tissues. Higher boost levels between 150% and 170% are feasible, but with slightly larger doses delivered to the rectum and urethra.