Dosimetric evaluation of high-Z inhomogeneity with modern algorithms: A collaborative study.

PURPOSE: To evaluate modern dose calculation algorithms with high-Z prosthetic devices used in radiation treatment. METHODS: A bilateral hip prosthetic patient was selected to see the effect of modern algorithms from the commercial system for plan comparisons. The CT data with dose constraints were sent to various institutions for dose calculations. The dosimetric parameters, D98%, D90%, D50% and D2% were compared. A water phantom with an actual prosthetic device was used to measure the dose using a parallel plate ionization chamber. RESULTS: Dosimetric variability in PTV coverage was significant (>10%) among various treatment planning algorithms. The comparison of PTV dosimetric parameters, D98%, D90%, D50% and D2% as well as organs at risk (OAR) have large discrepancies compared to our previous publication with older algorithms (https://doi.org/10.1016/j.ejmp.2022.02.007) but provides realistic dose distribution with better homogeneity index (HI). Backscatter and forward scatter attenuation of the prosthesis was measured showing differences <15.7% at the interface among various algorithms. CONCLUSIONS: Modern algorithms dose distributions have improved greatly compared to older generation algorithms. However, there is still significant differences at high-Z-tissue interfaces compared to the measurements. To ensure accuracy, it's important to take precautions avoiding placing any prosthesis in the beam direction and using type C algorithms.

Variability of Low-Z Inhomogeneity Correction in IMRT/SBRT: A Multi-Institutional Collaborative Study.

Dose-calculation algorithms are critical for radiation treatment outcomes that vary among treatment planning systems (TPS). Modern algorithms use sophisticated radiation transport calculation with detailed three-dimensional beam modeling to provide accurate doses, especially in heterogeneous medium and small fields used in IMRT/SBRT. While the dosimetric accuracy in heterogeneous mediums (lung) is qualitatively known, the accuracy is unknown. The aim of this work is to analyze the calculated dose in lung patients and compare the validity of dose-calculation algorithms by measurements in a low-Z phantom for two main classes of algorithms: type A (pencil beam) and type B (collapse cone). The CT scans with volumes (target and organs at risk, OARs) of a lung patient and a phantom build to replicate the human lung data were sent to nine institutions for planning. Doses at different depths and field sizes were measured in the phantom with and without inhomogeneity correction across multiple institutions to understand the impact of clinically used dose algorithms. Wide dosimetric variations were observed in target and OAR coverage in patient plans. The correction factor for collapsed cone algorithms was less than pencil beam algorithms in the small fields used in SBRT. The pencil beam showed ≈70% variations between measured and calculated correction factors for various field sizes and depths. For large field sizes the trends of both types of algorithms were similar. The differences in measured versus calculated dose for type-B algorithms were within ±10%. Significant variations in the target and OARs were observed among various TPS. The results suggest that the pencil beam algorithm does not provide an accurate dose and should not be considered with small fields (IMRT/SBRT). Type-B collapsed-cone algorithms provide better agreement with measurements, but still vary among various systems.

Dosimetric evaluation of high-Z inhomogeneity used for hip prosthesis: A multi-institutional collaborative study.

PURPOSE: A multi-institutional investigation for dosimetric evaluation of high-Z hip prosthetic device in photon beam. METHODS: A bilateral hip prosthetic case was chosen. An in-house phantom was built to replicate the human pelvis with two different prostheses. Dosimetric parameters: dose to the target and organs at risk (OARs) were compared for the clinical case generated by various treatment planning system (TPS) with varied algorithms. Single beam plans with different TPS for phantom using 6 MV and 15 MV photon beams with and without density correction were compared with measurement. RESULTS: Wide variations in target and OAR dosimetry were recorded for different TPS. For clinical case ideal PTV coverage was noted for plans generated with Corvus and Prowess TPS only. However, none of the TPS were able to meet plan objective for the bladder. Good correlation was noticed for the measured and the Pinnacle TPS for corrected dose calculation at the interfaces as well as the dose ratio in elsewhere. On comparing measured and calculated dose, the difference across the TPS varied from -20% to 60% for 6 MV and 3% to 50% for the 15 MV, respectively. CONCLUSION: Most TPS do not provide accurate dosimetry with high-Z prosthesis. It is important to check the TPS under extreme conditions of beams passing through the high-Z region. Metal artifact reduction algorithms may reduce the difference between the measured and calculated dose but still significant differences exist. Further studies are required to validate the calculational accuracy.

The COVID-19 Pandemic: Effects on Civil Registration of Births and Deaths and on Availability and Utility of Vital Events Data.

The complex and evolving picture of COVID-19-related mortality highlights the need for data to guide the response. Yet many countries are struggling to maintain their data systems, including the civil registration system, which is the foundation for detailed and continuously available mortality statistics. We conducted a search of country and development agency Web sites and partner and media reports describing disruptions to the civil registration of births and deaths associated with COVID-19 related restrictions.We found considerable intercountry variation and grouped countries according to the level of disruption to birth and particularly death registration. Only a minority of the 66 countries were able to maintain service continuity during the COVID-19 restrictions. In the majority, a combination of legal and operational challenges resulted in declines in birth and death registration. Few countries established business continuity plans or developed strategies to deal with the backlog when restrictions are lifted.Civil registration systems and the vital statistics they generate must be strengthened as essential services during health emergencies and as core components of the response to COVID-19.

Characteristics of Cancer Rehabilitation Fellowship Training Programs in the USA.

Cancer rehabilitation is emerging as a specialized field within Physical Medicine and Rehabilitation. The purpose of this systemic review is to summarize the various cancer rehabilitation fellowship programs in the USA and the scope of training in this discipline. Currently, four institutions offer such a training program. All of the fellowship directors were contacted about characteristics of their programs. The oldest program has been in existence since 2007. All of these programs are 1 year in duration and have between one and two fellowship positions annually. There have been total of 29 graduates as of July 2017. With regard to cancer rehabilitation care delivery model, all four centers reported inpatient consult teams and outpatient rehabilitation. Outpatient experience included electrodiagnosis, botulin toxin, and ultrasound-guided injections. Three of the four programs also reported the presence of an acute inpatient cancer rehabilitation service. A number of clinical rotations are available at each of the four programs with considerable variation. Comprehensive educational efforts are present in all programs with varying expectations for research.

Integrating community-based verbal autopsy into civil registration and vital statistics (CRVS): system-level considerations.

BACKGROUND: Reliable and representative cause of death (COD) statistics are essential to inform public health policy, respond to emerging health needs, and document progress towards Sustainable Development Goals. However, less than one-third of deaths worldwide are assigned a cause. Civil registration and vital statistics (CRVS) systems in low- and lower-middle-income countries are failing to provide timely, complete and accurate vital statistics, and it will still be some time before they can provide physician-certified COD for every death. Proposals: Verbal autopsy (VA) is a method to ascertain the probable COD and, although imperfect, it is the best alternative in the absence of medical certification. There is extensive experience with VA in research settings but only a few examples of its use on a large scale. Data collection using electronic questionnaires on mobile devices and computer algorithms to analyse responses and estimate probable COD have increased the potential for VA to be routinely applied in CRVS systems. However, a number of CRVS and health system integration issues should be considered in planning, piloting and implementing a system-wide intervention such as VA. These include addressing the multiplicity of stakeholders and sub-systems involved, integration with existing CRVS work processes and information flows, linking VA results to civil registration records, information technology requirements and data quality assurance. CONCLUSIONS: Integrating VA within CRVS systems is not simply a technical undertaking. It will have profound system-wide effects that should be carefully considered when planning for an effective implementation. This paper identifies and discusses the major system-level issues and emerging practices, provides a planning checklist of system-level considerations and proposes an overview for how VA can be integrated into routine CRVS systems.

Trends in ambulatory physician opioid prescription in the United States, 1997-2009.

OBJECTIVE: To describe the changing practice pattern of opioid medication prescription by health care providers and its relationship to shifts in the incidence of back pain, demographics, and health care access. DESIGN: Retrospective analysis of nationally representative databases. SETTING: In silico. PARTICIPANTS: Patients who presented at a set of randomly selected health care facilities on the days of data collection. METHODS: Nationally representative surveys from the Centers for Disease Control and Prevention (National Hospital and Ambulatory Medical Center Survey and National Ambulatory Medical Center Survey) were investigated for 3 ambulatory settings-emergency department (ED), primary care physician (PCP), and specialist physician offices-between the years 1997 and 2009. Diagnoses, prescription medications, insurance source, and demographics were determined. Weighted logistic regression modeling with the SAS program (SAS Institute, Cary, NC) was used to estimate 5-year odds ratios (ORs) and covariate effects. MAIN OUTCOME MEASUREMENTS: Diagnoses, prescription medications, insurance source, and demographics were measured. The relationships between opioid medication prescription and (1) the chief complaint and (2) back pain diagnoses were studied. Domain analysis was used to properly account for the stochasticity introduced by subset analyses. RESULTS: From 1997 to 2009, increasing all-diagnosis opioid prescription was accompanied by significant shifts in patient demographics and insurance access. For all-diagnosis opioid prescription, after we adjusted for age, gender, race, and insurance source, the increase persisted at a 5-year OR of 1.33, 1.29, and 1.53 for ED, PCP clinics, and specialist clinics (95% confidence interval 1.26-1.41, 1.19-1.40, and 1.37-1.69), respectively. The increasing prevalence of back pain diagnosis was eclipsed by increasing opioid prescriptions, estimated at 5-year ORs of 1.35, 1.38, and 1.75 for ED, PCP clinics, and specialist clinics (95% confidence interval 1.22-1.48, 1.19-1.61, 1.40-2.19), respectively. CONCLUSIONS: In the United States, from 1997-2009, (1) variable increases in opioid prescription across ambulatory care settings were not accounted for by changing demographics and health care access; (2) significant disparities existed in opioid prescription as a function of age, gender, race/ethnicity, and payer source; and (3) for back pain, increasing opioid prescription was not accounted for by changing incidence.

The value of physical examination in the diagnosis of hip osteoarthritis.

OBJECTIVE: To compare the sensitivity of physical examination (internal rotation of the hip) with radiographs (using the Kellgren-Lawrence grading scale) in the diagnosis of clinically significant hip osteoarthritis. DESIGN: Case Series, Retrospective chart review of hip pain patients that underwent fluoroscopically guided hip steroid and anesthetic injections. PARTICIPANTS: 10 patients with hip pain patients seen at an academic outpatient center over a 2 year period were analyzed. INTERVENTIONS: Fluoroscopically guided hip steroid and anesthetic injection. MAIN OUTCOME MEASURE: Pain relief and change in VAS pain score after intra-articular hip steroid and lidocaine injection was the main outcome measure. RESULTS: Based on Fisher's exact test, there was no association between severity of radiographic hip arthritis and pain relief with intra-articular anesthetic/steroid injection (p=0.45). Physical examination (provocative hip internal rotation) however was associated with a significant decrease in VAS pain score after intra-articular lidocaine and corticosteroid hip injection (p=0.022). CONCLUSION: Simple hip radiographs alone are not sufficient to diagnose clinically significant hip osteoarthritis. Physical examination (hip internal rotation) was found to be more accurate than simple radiographs in the diagnosis of clinically significant hip osteoarthritis. Radiographs seem to best utilized when they are an extension of the physical examination and patient history.

Functional assessment of the acute local and distal transplantation of human neural stem cells after spinal cord injury.

BACKGROUND CONTEXT: Spinal cord injury can lead to severe functional impairments secondary to axonal damage, neuronal loss, and demyelination. The injured spinal cord has limited regrowth of damaged axons. Treatment remains controversial, given inconsistent functional improvement. Previous studies demonstrated functional recovery of rats with spinal cord contusion after transplantation of rat fetal neural stem cells. PURPOSE: We hypothesized that acute transplantation of human fetal neural stem cells (hNSCs) both locally at the injury site as well as distally via intrathecal injection would lead to improved functional recovery compared with controls. STUDY DESIGN/SETTING: Twenty-four adult female Long-Evans hooded rats were randomized into four groups with six animals in each group: two experimental and two control. Functional assessment was measured after injury and then weekly for 6 weeks using the Basso, Beattie, and Bresnahan Locomotor Rating Score. Data were analyzed using two-sample t test and linear mixed-effects model analysis. METHODS: Posterior exposure and laminectomy at T10 level was used. Moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor with 10-g weight dropped from a height of 25 mm. Experimental subjects received either a subdural injection of hNSCs locally at the injury site or intrathecal injection of hNSCs through a separate distal laminotomy. Controls received control media injection either locally or distally. RESULTS: Statistically significant functional improvement was observed in local or distal hNSCs subjects versus controls (p=.034 and 0.016, respectively). No significant difference was seen between local or distal hNSC subjects (p=.66). CONCLUSIONS: Acute local and distal transplantation of hNSCs into the contused spinal cord led to significant functional recovery in the rat model. No statistical difference was found between the two techniques.

Adjuvant analgesics in cancer pain: a review.

Adjuvant analgesics (co-analgesics) are medications whose primary indication is the management of a medical condition with secondary effects of analgesia. Cancer pain is multifactorial and often involves inflammatory, nociceptive, and neuropathic pain subtypes. Adjuvant analgesics used in conjunction with opioids have been found to be beneficial in the management of many cancer pain syndromes; however, they are currently underutilized. Antidepressants, anticonvulsants, local anesthetics, topical agents, steroids, bisphosphonates, and calcitonin are all adjuvants which have been shown to be effective in the management of cancer pain syndromes. When utilizing analgesic adjuvants in the treatment of cancer pain, providers must take into account the particular side effect profile of the medication. Ideally, adjuvant analgesics will be initiated at lower dosages and escalated as tolerated until efficacy or adverse effects are encountered.

Is chronic opioid use a negative predictive factor for response to cervical epidural steroid injections?

BACKGROUND: Cervical epidural steroid injections (ESIs) are often used to treat patients with neck and upper extremity pain associated with a cervical radiculopathy. The effect of chronic opioid use in cervical radiculopathy patients managed with ESIs is unknown; past studies suggest that these patients may behave differently than opioid naïve patients. The purpose of this study is to determine the effect of chronic (greater than 6 months) opioid use on the immediate outcome of cervical ESIs. METHODS: A two year retrospective chart review identified 22 consecutive patients with cervical radiculopathy who underwent a single level interlaminar cervical ESI, main outcome variable was > 50% pain relief on VAS at follow up. Inclusion factors were unilateral disc protrusion, exclusion factors were severe central canal or foraminal stenosis, spondylolithesis, spinal instability, cord edema, or with multi-level disc protrusions. RESULTS: Using a linear logistic regression analysis on both patient demographics and physical exam measures, the most significant explanatory model was the use of opiates at the time of injection; 70% of opioid naïve patients had a favorable outcome while only 20% of patients managed with chronic opioids had relief (p= 0.06). CONCLUSIONS: Patients managed with opioids chronically may respond in a different manner to ESIs when compared to opioid naïve patients.

Adverse effects of corticosteroids on bone metabolism: a review.

Glucocorticoid (GC) exposure is the most common etiology of drug-induced (secondary) osteoporosis. Twenty percent of all cases of osteoporosis have been attributed to GC exposure. Significant risk factors for the development of fractures after GC exposure include age older than 65 years, prolonged GC exposure (>3 months), positive family history of osteoporosis, and low calcium intake. GCs are known to inhibit bone remodeling and to increase fracture risk. GC exposure alters the fragile balance between osteoclast and osteoblast activity in bone metabolism. GC stimulates osteoclast-mediated bone resorption and reduces osteoblast-mediated bone formation, which results in increased overall net bone resorption. Specifically, the 2 main effects of GCs on bone metabolism are (1) inducing apoptosis in osteoblasts and osteocytes, thereby decreasing bone formation, and (2) prolonging the lifespan of osteoclasts and increasing bone resorption. The risk of fracture decreases 3 months after cessation of GC therapy; thus, a 3-month period may be ideal between GC exposures in patients at high risk for the development of osteoporosis. Patients managed with GCs who are at high risk for the development of secondary osteoporosis should have appropriate diagnostic testing; pre-GC exposure medication management (ie, use of bisphosphonates, human parathyroid hormone); and a limitation of GC therapy, with a wait period of 3 months between GC exposures if possible.

Pulmonary cement embolism after kyphoplasty.

An 80-year-old female with a history of osteoporosis was evaluated for sudden onset axial low back pain with bilateral lower extremity weakness, hyperreflexia, pain, urinary retention, and decreased rectal tone. Computed tomography of the lumbar spine revealed L1 compression fracture, retropulsion of bone causing spinal canal compromise with associated severe central canal stenosis. Following cement kyphoplasty of L1 with polymethyl methacrylate, the patient developed tachycardia and dyspnea. Chest radiograph and computed tomographic pulmonary angiogram revealed a large collection of hyperdense material within the right lower lobe pulmonary artery, consistent with pulmonary cement emboli. Management and imaging are discussed.

Fluoroscopically guided supraglenoid tubercle steroid injections for the management of biceps tendonitis.

BACKGROUND: The management of bicipital tendonitis can be challenging to the clinician. Traditionally, blind injections near the bicipital groove have been performed by clinicians with risk of bicipital tendon rupture or atrophy. Because of the inaccuracy and risk associated with blind bicipital tendon steroid injections, we sought to ascertain whether a fluoroscopically guided steroid injection into the region of the origin of the long head of the bicipital tendon (supraglenoid tubercle) was efficacious. METHODS: A retrospective chart review of 6 consecutive patients with a diagnosis of bicipital tendonitis was performed. All patients underwent a fluoroscopically guided steroid/anesthetic injection into the supraglenoid tubercle of the shoulder. The main outcome measure was post-procedure change in visual analog pain scale; the secondary outcome was the physical examination (presence of a Speed's test). RESULTS: Ten cases were identified, but only 6 had complete data and were included in the analysis. Five of the 6 patients experienced a reduction in pain by 50% at follow-up. DISCUSSION: A fluoroscopically guided block injected into the supraglenoid tubercle may be effective in the management of bicipital tendonitis.