Monte Carlo calculated absorbed-dose energy dependence of EBT3 and EBT4 films for 5-200 MeV electrons and 100 keV-15 MeV photons.

PURPOSE: To use Monte Carlo simulations to study the absorbed-dose energy dependence of GAFChromic EBT3 and EBT4 films for 5-200 MeV electron beams and 100 keV-15 MeV photon beams considering two film compositions: a previous EBT3 composition (Bekerat et al.) and the final composition of EBT3/current composition of EBT4 (Palmer et al.). METHODS: A water phantom was simulated with films at 5-50 mm depth in 5 mm intervals. The water phantom was irradiated with flat, monoenergetic 5-200 MeV electron beams and 100 and 150 keV kilovoltage and 1-15 MeV megavoltage photon beams and the dose to the active layer of the films was scored. Simulations were rerun with the films defined as water to compare the absorbed-dose response of film to water, f - 1 ( Q ) = D f i l m D w a t e r $f^{-1}(Q)=\frac{D_{film}}{D_{water}}$ . RESULTS: For electrons, the Bekerat et al. composition had variations in f - 1 ( Q ) $f^{-1}(Q)$ of up to ( 1.9 ± 0.1 ) % $(1.9\,\pm \,0.1)\%$ from 5 to 200 MeV. Similarly, the Palmer et al. composition had differences in f - 1 ( Q ) $f^{-1}(Q)$ up to ( 2.5 ± 0.2 ) % $(2.5 \pm 0.2)\%$ from 5 to 200 MeV. For photons, f - 1 ( Q ) $f^{-1}(Q)$ varied up to ( 2.4 ± 0.3 ) % $(2.4 \pm 0.3)\%$ and ( 4.5 ± 0.7 ) % $(4.5 \pm 0.7)\%$ from 100 keV to 15 MeV for the Bekerat et al. and Palmer et al. compositions, respectively. The depth of films did not appear to significantly affect f - 1 ( Q ) $f^{-1}(Q)$ for photons at any energy and for electrons at energies > $>$  50 MeV. However, for 5 and 10 MeV electrons, decreases of up to ( 10.2 ± 1.1 ) % $(10.2 \pm 1.1)\%$ in f - 1 ( Q ) $f^{-1}(Q)$ were seen due to stacked films and increased beam attenuation in films compared to water. CONCLUSIONS: The up to ( 2.5 ± 0.2 ) % $(2.5 \pm 0.2)\%$ and ( 4.5 ± 0.7 ) % $(4.5 \pm 0.7)\%$ variations in f - 1 ( Q ) $f^{-1}(Q)$ for electrons and photons, respectively, across the energies considered in this study indicate the importance of calibrating films with the energy intended for measurement. Additionally, this work emphasizes potential issues with stacking films to measure depth dose curves, particularly for electron beams with energies ≤ $\le$ 10 MeV.

Mini-GRID radiotherapy on the CLEAR very-high-energy electron beamline: collimator optimization, film dosimetry, and Monte Carlo simulations.

Objective.Spatially-fractionated radiotherapy (SFRT) delivered with a very-high-energy electron (VHEE) beam and a mini-GRID collimator was investigated to achieve synergistic normal tissue-sparing through spatial fractionation and the FLASH effect.Approach.A tungsten mini-GRID collimator for delivering VHEE SFRT was optimized using Monte Carlo (MC) simulations. Peak-to-valley dose ratios (PVDRs), depths of convergence (DoCs, PVDR ≤ 1.1), and peak and valley doses in a water phantom from a simulated 150 MeV VHEE source were evaluated. Collimator thickness, hole width, and septal width were varied to determine an optimal value for each parameter that maximized PVDR and DoC. The optimized collimator (20 mm thick rectangular prism with a 15 mm × 15 mm face with a 7 × 7 array of 0.5 mm holes separated by 1.1 mm septa) was 3D-printed and used for VHEE irradiations with the CERN linear electron accelerator for research beam. Open beam and mini-GRID irradiations were performed at 140, 175, and 200 MeV and dose was recorded with radiochromic films in a water tank. PVDR, central-axis (CAX) and valley dose rates and DoCs were evaluated.Main results.Films demonstrated peak and valley dose rates on the order of 100 s of MGy/s, which could promote FLASH-sparing effects. Across the three energies, PVDRs of 2-4 at 13 mm depth and DoCs between 39 and 47 mm were achieved. Open beam and mini-GRID MC simulations were run to replicate the film results at 200 MeV. For the mini-GRID irradiations, the film CAX dose was on average 15% higher, the film valley dose was 28% higher, and the film PVDR was 15% lower than calculated by MC.Significance.Ultimately, the PVDRs and DoCs were determined to be too low for a significant potential for SFRT tissue-sparing effects to be present, particularly at depth. Further beam delivery optimization and investigations of new means of spatial fractionation are warranted.

A feasibility study of ultra-high dose rate mini-GRID therapy using very-high-energy electron beams for a simulated pediatric brain case.

Ultra-high dose rate (UHDR, >40 Gy/s), spatially-fractionated minibeam GRID (mini-GRID) therapy using very-high-energy electrons (VHEE) was investigated using Monte Carlo simulations. Multi-directional VHEE treatments with and without mini-GRID-fractionation were compared to a clinical 6 MV volumetric modulated arc therapy (VMAT) plan for a pediatric glioblastoma patient using dose-volume histograms, volume-averaged dose rates in critical patient structures, and planning target volume D98s. Peak-to-valley dose ratios (PVDRs) and dose rates in organs at risk (OARs) were evaluated due to their relevance for normal-tissue sparing in FLASH and spatially-fractionated techniques. Depths of convergence, defined where the PVDR is first ≤1.1, and depths at which dose rates fall below the UHDR threshold were also evaluated. In a water phantom, the VHEE mini-GRID treatments presented a surface (5 mm depth) PVDR of (51±2) and a depth of convergence of 42 mm at 150 MeV and a surface PVDR of (33±1) with a depth of convergence of 57 mm at 250 MeV. For a pediatric GBM case, VHEE treatments without mini-GRID-fractionation produced 25% and 22% lower volume-averaged doses to OARs compared to the 6 MV VMAT plan and 8/9 and 9/9 of the patient structures were exposed to volume-averaged dose rates >40 Gy/s for the 150 MeV and 250 MeV plans, respectively. The 150 MeV and 250 MeV mini-GRID treatments produced 17% and 38% higher volume-averaged doses to OARs and 3/9 patient structures had volume-averaged dose rates above 40 Gy/s. VHEE mini-GRID plans produced many comparable dose metrics to the clinical VMAT plan, encouraging further optimization.

Percutaneous treatments for residual and/or phantom limb pain in adults with lower-extremity amputations: A narrative review.

Residual limb pain (RLP) and phantom limb pain (PLP) profoundly affect the lives of many individuals who have undergone lower- or upper-extremity amputation. Despite the considerable impact of RLP/PLP on quality of life in persons with amputation, there have been few attempts to evaluate the efficacy of percutaneous interventions in the treatment of RLP and/or PLP. This narrative review evaluates the effectiveness of percutaneous treatments for RLP and/or PLP in patients after lower-extremity amputation. Peripheral nerve stimulation, alcohol neurolysis, conventional thermal radiofrequency ablation, perineural corticosteroid injection, botulinum toxin injection, and etanercept injection were associated with varying success rates. Wide confidence intervals and small treatment cohorts impede assessments of overall success. High-quality studies of nonsurgical, percutaneous treatments for RLP and/or PLP are lacking. Well-designed randomized controlled trials and large cohort studies with comparison groups using validated outcomes are needed to determine the effectiveness of nonsurgical interventions for the treatment of RLP and PLP.

Monte Carlo optimization of a GRID collimator for preclinical megavoltage ultra-high dose rate spatially-fractionated radiation therapy.

Objective. A 2-dimensional pre-clinical SFRT (GRID) collimator was designed for use on the ultra-high dose rate (UHDR) 10 MV ARIEL beamline at TRIUMF. TOPAS Monte Carlo simulations were used to determine optimal collimator geometry with respect to various dosimetric quantities.Approach. The GRID-averaged peak-to-valley dose ratio (PVDR) and mean dose rate of the peaks were investigated with the intent of maximizing both values in a given design. The effects of collimator thickness, focus position, septal width, and hole width on these metrics were found by testing a range of values for each parameter on a cylindrical GRID collimator. For each tested collimator geometry, photon beams with energies of 10, 5, and 1 MV were transported through the collimator and dose rates were calculated at various depths in a water phantom located 1.0 cm from the collimator exit.Main results. In our optimization, hole width proved to be the only collimator parameter which increased both PVDR and peak dose rates. From the optimization results, it was determined that our optimized design would be one which achieves the maximum dose rate for a PVDR≥5at 10 MV. Ultimately, this was achieved using a collimator with a thickness of 75 mm, 0.8 mm septal and hole widths, and a focus position matched to the beam divergence. This optimized collimator maintained the PVDR of 5 in the phantom between water depths of 0-10 cm at 10 MV and had a mean peak dose rate of3.06±0.02Gys-1at 0-1 cm depth.Significance. We have investigated the impact of various GRID-collimator design parameters on the dose rate and spatial fractionation of 10, 5, and 1 MV photon beams. The optimized collimator design for the 10 MV ultra-high dose rate photon beam could become a useful tool for radiobiology studies synergizing the effects of ultra-high dose rate (FLASH) delivery and spatial fractionation.

A comparison of the effectiveness of cervical medial branch radiofrequency ablation for chronic facet joint syndrome in patients selected by two common medial branch block paradigms.

Background: Cervical medial branch radiofrequency ablation (CMBRFA) is effective when patients are selected by dual medial branch blocks (MBBs). SIS guidelines recommend 100% pain improvement after dual comparative MBBs before CMBRFA; however, our prior investigation showed similar outcomes in those selected by a lesser strict paradigm. Objective: Compare pain and patient impression of improvement after CMBRFA in individuals stratified by a less stringent (80-99%) dual MBB response than those selected by the 100% criteria. Design: Cross-sectional study. Methods: Follow-up was conducted via standardized telephone survey at ≥6 months post-CMBRFA to obtain Numerical Rating Scale (NRS) pain and Patient Global Impression of Change (PGIC) scores. Primary and secondary outcomes were within-group and between-group differences in the proportions of patients reporting ≥50% NRS score reduction and PGIC scores. Results: Medical records of 195 consecutive patients were reviewed; 100 individuals were analyzed. 48% (95% CI 35-61%) and 52% (95% CI 37-67%) of the 80-99% and 100% MBB groups, reported ≥50% pain reduction at ≥6 months post-CMBRFA. 74% (95% CI 63-85%) and 67% (95% CI 52-81%) of the 80-99% and 100% MBB groups reported a PGIC score consistent with "improved" or "very much improved." There were no significant between-group differences in any outcome at any time point. Conclusions: We observed similar rates of pain relief and global improvement after CMBRFA in patients selected by dual MBBs with ≥80% symptom relief versus 100% relief. This provides evidence that a more practical criteria, compared to a more strict selection paradigm, may result in similar clinical outcomes.

Corticosteroid and Local Anesthetic Use Trends for Large Joint and Bursa Injections: Results of a Survey of Sports Medicine Physicians.

BACKGROUND: Physician decision-making surrounding choices for large joint and bursa injections is poorly defined, yet influences patient safety and treatment effectiveness. OBJECTIVE: To identify practice patterns and rationale related to injectate choices for large joint and bursal injections performed by physician members of the American Medical Society for Sports Medicine (AMSSM). DESIGN: An electronic survey was sent to 3400 members of the AMSSM. Demographic variables were collected: primary specialty (residency), training location, practice location, years of clinical experience, current practice type, and rationale for choosing an injectate. PARTICIPANTS: A total of 674 physicians responded (minimum response rate of 20%). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Outcomes of interest included corticosteroid type and dose, local anesthetic type, and total injectate volume for each large joint or bursa (hip, knee, and shoulder). RESULTS: Most respondents used triamcinolone (50% to 56% of physicians, depending on injection location) or methylprednisolone (25% to 29% of physicians), 21 to 40 mg (53% to 60% of physicians), diluted with lidocaine (79% to 87%) for all large joint or bursa injections. It was noted that 36.2% (244/674) of respondents reported using >40 mg for at least one injection type. Most (90.5%, 610/674) reported using an anesthetic other than ropivacaine for at least one type of joint or bursa injection. Physicians who reported lidocaine use were less likely to report that their injectate choice was based on the literature that they reviewed (odds ratio [OR] 0.41 [0.27-0.62], P < .001). Respondents predominantly used 5 to 7 mL of total injectate for all large joints or bursae (45% to 54% of respondents), except for the pes anserine bursa, where 3-4 mL was more common (51% of physicians). CONCLUSIONS: It appears that triamcinolone and methylprednisolone are the most commonly used corticosteroids for sports medicine physicians; most physicians use 21 to 40 mg of corticosteroid for all injections, and lidocaine is the most-often used local anesthetic; very few use ropivacaine. Over one-third of respondents used high-dose (>40 mg triamcinolone or methylprednisolone) for at least one joint or bursa.

The Effectiveness of Dorsal Root Ganglion Neurostimulation for the Treatment of Chronic Pelvic Pain and Chronic Neuropathic Pain of the Lower Extremity: A Comprehensive Review of the Published Data.

OBJECTIVE: To evaluate the effectiveness of dorsal root ganglion neurostimulation for the treatment of refractory, focal pain in the pelvis and lower extremities. DESIGN: Systematic review. OUTCOME MEASURES: The primary outcome was ≥50% pain relief. Secondary outcomes were physical function, mood, quality of life, opioid usage, and complications. RESULTS: One pragmatic randomized controlled trial, four prospective cohort studies, and eight case series met the inclusion criteria. A worst-case scenario analysis from the randomized controlled trial reported ≥50% pain relief in 74% of patients with dorsal root ganglion neurostimulation vs. 51% of patients who experienced at least 50% relief with spinal cord stimulation at 3 months. Cohort data success rates ranged from 43% to 83% at ≤6 months and 27% to 100% at >6 months. Significant improvements were also reported in the secondary outcomes assessed, including mood, quality of life, opioid usage, and health care utilization, though a lack of available quantitative data limits further statistical analysis. Complication rates vary, though the only randomized controlled trial reported a higher rate of adverse events than that seen with traditional neurostimulation. CONCLUSIONS: In accordance with the Grades of Recommendation, Assessment, Development, and Evaluation system, low-quality evidence supports dorsal root ganglion neurostimulation as a more effective treatment than traditional neurostimulation for pain and dysfunction associated with complex regional pain syndrome or causalgia. Very low-quality evidence supports dorsal root ganglion neurostimulation for the treatment of chronic pelvic pain, chronic neuropathic groin pain, phantom limb pain, chronic neuropathic pain of the trunk and/or limbs, and diabetic neuropathy.

Ultrasound evaluation of the patellar tendon and Achilles tendon and its association with future pain in distance runners.

Objectives: To examine whether asymptomatic ultrasonographic abnormalities in the Achilles and patellar tendons in runners are associated with an increased risk of pain development.Methods: This is a longitudinal, prospective cohort study with 139 runners recruited at a half and full marathon race. Ultrasound examination of the Achilles and patellar tendons was performed bilaterally the day prior to the race. Self-reported injury data were collected at 1, 3, 6 and 12 months. 104 (74.8%) runners were included in the data analysis.Results: Ultrasonographic tendon abnormalities were found in 24.1% of the Achilles and in 23.1% of the patellar tendons prior to the race. Runners with tendon abnormality were 2-3 times more likely to develop pain within 12 months than those without (relative risk = 3.14, p = 0.010 for Achilles; relative risk = 2.52, p = 0.008 for patellar tendon). After adjusting for gender, age, years of running, average miles per week of running over a year, and pre-race pain, runners with ultrasound abnormality were about 3 times (hazard ratio = 2.89, p = 0.039 for Achilles; hazard ratio = 2.73, p = 0.030 for patellar tendon) more likely to develop pain after the race. Tendon delamination was most strongly associated with pain in both the Achilles (relative risk = 6.00; p = 0.001) and patellar tendons (relative risk = 3.81; p = 0.001).Conclusions: Structural changes in asymptomatic tendons were found in almost 25% of runners. Presence of structural changes was associated with increased development of Achilles and patellar tendon pain within one year.

The Use of Vitamins, Supplements, Herbs, and Essential Oils in Rehabilitation.

The term, dietary supplement, refers to a broad category of products, including herbal or plant-based extracts, micronutrients, and food-based nutraceuticals. The use of supplements in clinical rehabilitation requires clear communication from patients and health care providers to understand the types of products used and their effects on health. Providers should distinguish between using micronutrient supplementation for therapeutic purposes and treatment of nutritional deficiency in patients with malnutrition syndromes. Evidence supports micronutrient and nutraceutical supplementation use to improve pain, functional status, and inflammation. There is little evidence on the use of herbal or plant-based extracts in therapeutic rehabilitation; larger studies are warranted.

Image guidance used for large joint and bursa injections; a survey study.

Objectives: To determine the current rates of use of available image guidance modalities for large joint and bursal injections, in addition to their relationships to physician demographics.Methods: An electronic survey was sent to 3,400 members of the American Medical Society for Sports Medicine (AMSSM), examining types of guidance used for each large joint and bursal injection.Results: A total of 674 sports medicine physicians responded to the survey. Intra-articular hip and glenohumeral joint injections were more commonly performed with ultrasound guidance, while palpation-guidance was more common with all other injections. Physicians who specialized in Physical Medicine & Rehabilitation (PM&R) were more likely to use ultrasound for trochanteric bursa (p = 0.007, OR = 4.16 [1.46-11.8]), while internal medicine-, pediatrics-, and family medicine-trained physicians were more likely to use palpation guidance for at least one joint (p < 0.05). Physicians with fewer years of experience were more likely to use ultrasound for glenohumeral joint injections (p ≤ 0.002 for all age groups with less than 20 years of experience, ORs ranging from 6.3 to 9.2).Conclusion: Palpation-guidance is the most common technique used for large joint and bursal injections, other than for glenohumeral and hip joint injections. PM&R-trained physicians and those with less experience tend to use ultrasound more frequently.

Infections After Large Joint or Bursa Injection: A Survey of 554 Sports Medicine Physicians.

OBJECTIVE: Despite the ubiquity of intra-articular and bursal injections for the treatment of joint pain and bursitis, relatively little literature is available on the prevalence of infection after these procedures. The aim of this study was to identify the number of infections recalled by sports medicine physicians who perform injections of large joints and bursae at least once per month. DESIGN: A survey of physician members of the American Medical Society for Sports Medicine identified the reported number of recalled infections for each large joint/bursal location. RESULTS: Of a total of 554 physicians, only 31 infections were recalled by 27 physicians. Only 4.87% of all physicians were aware of an infection after an injection during their career. On average, one infection was recalled of 170 physician-years in practice. No differences in infection rates were observed when comparing primary specialties (P = 0.281). CONCLUSIONS: This study, the largest to date, demonstrates that sports medicine physicians rarely encounter infections after large joint and bursa injections. Though rare, because of their catastrophic nature, risk mitigation strategies should be maintained.

Comparison of Varying Corticosteroid Type, Dose, and Volume for the Treatment of Pain in Small- and Intermediate-Size Joint Injections: A Narrative Review.

OBJECTIVE: To systematically evaluate the scientific literature examining the effect of corticosteroid type, dose, and volume of small- and intermediate-size joint injections on pain and function. TYPE: Narrative review. LITERATURE SURVEY: Medline (PubMed), Cochrane Central Register of Controlled Trial, and SportDiscus databases were searched. METHODOLOGY: Inclusion criteria included prospective studies evaluating pain- and/or function-related improvements following a corticosteroid injection of a small- or intermediate-size joint. SYNTHESIS: A total of 28 articles were included, all studying patients with osteoarthritis and/or rheumatoid arthritis. Eleven studies were randomized-controlled trials comparing corticosteroid injections to a control treatment and three were randomized trials comparing corticosteroid dose or type; the rest were prospective case series without a control. Most studies used 10 to 20 mg of methylprednisolone or triamcinolone for small joints and 20 to 40 mg for intermediate joints; wrist joints were the only joint studied that directly compared doses-20 mg was noninferior to 40 mg. Triamcinolone hexacetonide was found to be superior to methylprednisolone in the interphalangeal finger joints in a single randomized-controlled trial; no other studies compared steroid types in any joint. No studies evaluated the effect of volume on clinical outcomes. CONCLUSIONS: Very few studies directly examine the effect of corticosteroid type, corticosteroid dose, or injectate volume on clinical outcomes for small- or intermediate-size joint arthralgia. Future studies are needed to better elucidate the most effective treatment protocols. LEVEL OF EVIDENCE: IV.

Trends in steroid agent and diluent choices for epidural steroid injections: a survey of Spine Intervention Society physicians.

BACKGROUND: Epidural steroid injections (ESIs) are a frequently used treatment for refractory radicular spinal pain. ESIs, particularly transforaminal epidural steroid injections (TFESI), may provide pain relief and delay the need for surgery. Corticosteroid agent and diluent choices are known to impact the safety of ESIs. In particular, the risk of embolization with particulate corticosteroids has led to recommendations for non-particulate steroid use by the Multisociety Pain Workgroup. Additionally, there is in vitro evidence that ropivacaine can crystalize in the presence of dexamethasone, potentially creating a particulate-like injectate. Despite widespread use and known risk mitigation strategies, current practice trends related to steroid and diluent choices are unknown. OBJECTIVE: Identify the use of particulate versus non-particulate corticosteroids for epidural steroid injections in the cervical and lumbar spine, as well as local anesthetics commonly used as diluents during these procedures. METHODS: Cross-sectional survey study of 314 physician members of the Spine Interventional Society. RESULTS: 41% and 9% of providers reported using particulate corticosteroids during lumbar TFESIs and cervical TFESI, respectively. Four per cent of providers reported the use of ropivacaine in cervical TFESIs. Forty-four per cent of respondents reported using anesthetic in cervical interlaminar ESIs. 21% of providers report using high volumes (> 4.5 mL) during cervical interlaminar ESIs. CONCLUSION: Current trends, as assessed by this survey study, indicate substantial variability in steroid and diluent choice for ESIs. Patterns were identified that may impact patient safety including the continued use of particulate corticosteroids for TFESIs and the use of ropivacaine during TFESIs by a subset of respondents.

Relationship between human leukocyte antigen alleles and risk of Kaposi's sarcoma in Cameroon.

Several studies published to date report associations between human leukocyte antigen (HLA) alleles and different types of Kaposi's Sarcoma (KS). However, there is little concordance between the HLA alleles identified and the populations studied. To test whether HLA alleles associate with KS in a Cameroonian case-control study, we performed high-resolution HLA typing in KSHV seropositive individuals. Among HIV-positive individuals, carriers of HLA-B*14:01 were at a significantly higher risk of AIDS-KS (p = 0.033). For HIV-negative patients, a gene-wise comparison of allele frequencies identified the HLA-B (p = 0.008) and -DQA1 (p = 0.002) loci as possible risk factors for endemic KS. Our study provides additional understanding of genetic determinants of KS and their implications in disease pathogenesis. Further validation of these findings is needed to define the functional relevance of these associations.