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1.
Acute Med ; 22(3): 130-136, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37746681

RESUMO

BACKGROUND: Education, research, and Quality Improvement (QI) are key enablers for high quality care. We aimed to map the capability of Acute Medical Units (AMUs) to facilitate excellence in these areas. METHODS: AMUs were surveyed in an organisational questionnaire within the Society for Acute Medicine Benchmarking Audit 2021. RESULTS: 143 units participated. 80 units had a QI lead, 24 had a research lead and 99 had a medical education lead. 15 units had all three leadership roles. Most QI work considered service structure rather than changes in processes or care outcomes. CONCLUSION: The organisational capability of AMUs in the strategic areas considered is variable. Improving leadership and disseminating learning could help build a strategic foundation for acute medicine to grow.


Assuntos
Medicina , Melhoria de Qualidade , Humanos , Benchmarking , Liderança , Inquéritos e Questionários
2.
Biomed Pharmacother ; 127: 110165, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32403043

RESUMO

Acute myocardial ischemia and reperfusion injury (IRI) underly the detrimental effects of coronary heart disease on the myocardium. Despite the ongoing advances in reperfusion therapies, there remains a lack of effective therapeutic strategies for preventing IRI. Growth hormone secretagogues (GHS) have been demonstrated to improve cardiac function, attenuate inflammation and modulate the autonomic nervous system (ANS) in models of cardiovascular disease. Recently, we demonstrated a reduction in infarct size after administration of hexarelin (HEX), in a murine model of myocardial infarction. In the present study we employed a reperfused ischemic (IR) model, to determine whether HEX would continue to have a cardioprotective influence in a model of higher clinical relevance. Myocardial ischemia was induced by transient ligation of the left descending coronary artery (tLAD) in C57BL/6 J mice followed by HEX (0.3 mg/kg/day; n = 20) or vehicle (VEH) (n = 18) administration for 21 days, first administered immediately prior-to reperfusion. IR-injured and sham mice were subjected to high-field magnetic resonance imaging to assess left ventricular (LV) function, with HEX-treated mice demonstrating a significant improvement in LV function compared with VEH-treated mice. A significant decrease in interstitial collagen, TGF-ß1 expression and myofibroblast differentiation was also seen in the HEX-treated mice after 21 days. HEX treatment shifted the ANS balance towards a parasympathetic predominance; combined with a significant decrease in cardiac troponin-I and TNF-α levels, these findings were suggestive of an anti-inflammatory action on the myocardium mediated via HEX. In this model of IR, HEX appeared to rebalance the deregulated ANS and activate vagal anti-inflammatory pathways to prevent adverse remodelling and LV dysfunction. There are limited interventions focusing on IRI that have been successful in improving clinical outcome in acute myocardial infarction (AMI) patients, this study provides compelling evidence towards the translational potential of HEX where all others have largely failed.


Assuntos
Infarto do Miocárdio/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Oligopeptídeos/farmacologia , Função Ventricular Esquerda/efeitos dos fármacos , Animais , Anti-Inflamatórios/farmacologia , Modelos Animais de Doenças , Inflamação/tratamento farmacológico , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Troponina I/metabolismo , Disfunção Ventricular Esquerda/prevenção & controle
3.
Artigo em Inglês | MEDLINE | ID: mdl-24316175

RESUMO

The primary objective of this study was to determine the safety of lofexidine, an α2 receptor agonist, alone and concurrent with cocaine in non-treatment seeking cocaine-dependent or cocaine-abusing participants. After screening, eligible participants received double-blind, randomized infusions of saline and 20mg of cocaine on Day 1, and saline and 40mg of cocaine on Day 2. Subjects were randomized and started receiving daily administration of placebo (N=4) or lofexidine on Day 3 and continued on this schedule until Day 7. Two dosing regimens for lofexedine were investigated: 0.8 QID (N=3) and 0.2mg QID (N=11). On Days 6 and 7, subjects received double-blind infusions of saline and 20mg of cocaine on Day 6, and saline and 40mg of cocaine on Day 7. The data reveal a notable incidence of hemodynamic-related AEs over the course of the study. Two of the three participants at the 0.8mg dose level discontinued, and five of 11 participants at the 0.2mg dose level were withdrawn (or voluntarily discontinued) after hemodynamic AEs. Subjective effects and cardiovascular data were derived from all participants who were eligible to receive infusions (i.e., did not meet stopping criteria) on Days 6 and 7 (6 received lofexidine 0.2mg, QID and 4 received placebo, QID). As expected, cocaine significantly increased heart rate and blood pressure, as well as several positive subjective effects. There was a trend for lofexidine to decrease cocaine-induced cardiovascular changes and cocaine-induced ratings for "any drug effect", "good effects", and "desire cocaine", but sample size issues limit the conclusions that can be drawn. Despite the trends to reduce cocaine-induced subjective effects, cardiovascular AEs may limit future utility of lofexidine as a treatment for this population.


Assuntos
Comportamento Aditivo/tratamento farmacológico , Pressão Sanguínea/efeitos dos fármacos , Clonidina/análogos & derivados , Cocaína/administração & dosagem , Cocaína/efeitos adversos , Frequência Cardíaca/efeitos dos fármacos , Adolescente , Agonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Agonistas de Receptores Adrenérgicos alfa 2/efeitos adversos , Agonistas de Receptores Adrenérgicos alfa 2/uso terapêutico , Adulto , Clonidina/administração & dosagem , Clonidina/efeitos adversos , Clonidina/uso terapêutico , Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Inibidores da Captação de Dopamina/administração & dosagem , Inibidores da Captação de Dopamina/efeitos adversos , Método Duplo-Cego , Esquema de Medicação , Interações Medicamentosas , Usuários de Drogas/psicologia , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Adulto Jovem
4.
Drug Alcohol Depend ; 132(1-2): 189-94, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23474358

RESUMO

BACKGROUND: Case reports and series indicate that ketamine, an anesthetic agent, causes lower urinary tract symptoms (LUTS). This study explored whether ketamine users were more likely to report LUTS compared to other substance users. METHODS: Participants were recruited through an online survey on erowid.org, a drug information website. A notice posted on the website invited substance users to participate in a web-based survey on "drug use and health". The notice did not mention ketamine, or other aspects of the research questions, to avoid participation bias. The anonymous survey collected demographics, drug use history, and history of LUTS (urinary frequency, urgency, incontinence, hematuria, and dysuria). RESULTS: Of 18,802 participants, 18.7% and 5.8% reported ever (lifetime) and recent (past-6-month) use of ketamine, respectively. Prevalence of LUTS among ever, recent, and never users of ketamine were 28%, 30%, and 24% respectively. Multivariate analysis showed significant associations between recent ketamine use and urinary symptoms. For each additional day of ketamine use in the last 180 days, the odds of developing urinary frequency, urgency, dysuria, and hematuria increased by 1.6%, 1.4%, 1.7%, and 1.9% respectively. One excess case of urinary frequency was reported per 17 recent users of ketamine. CONCLUSION: Compared to non-users, recent ketamine users had increased odds of LUTS. This is the first large-scale community-based study assessing the association of non-medical ketamine use with LUTS. Associations between ketamine and urological symptoms should be confirmed through longitudinal studies.


Assuntos
Anestésicos Dissociativos , Ketamina , Transtornos Relacionados ao Uso de Substâncias/complicações , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Doenças Urológicas/induzido quimicamente , Doenças Urológicas/epidemiologia , Adulto , Coleta de Dados , Interpretação Estatística de Dados , Disuria/induzido quimicamente , Disuria/epidemiologia , Feminino , Hematúria/induzido quimicamente , Hematúria/epidemiologia , Humanos , Internet , Masculino , Fatores Socioeconômicos , Doenças Urológicas/fisiopatologia , Adulto Jovem
5.
Neurology ; 78(8): 585-9, 2012 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-22351796

RESUMO

OBJECTIVE: To evaluate whether spinal cord intraoperative monitoring (IOM) with somatosensory and transcranial electrical motor evoked potentials (EPs) predicts adverse surgical outcomes. METHODS: A panel of experts reviewed the results of a comprehensive literature search and identified published studies relevant to the clinical question. These studies were classified according to the evidence-based methodology of the American Academy of Neurology. Objective outcomes of postoperative onset of paraparesis, paraplegia, and quadriplegia were used because no randomized or masked studies were available. RESULTS AND RECOMMENDATIONS: Four Class I and 8 Class II studies met inclusion criteria for analysis. The 4 Class I studies and 7 of the 8 Class II studies reached significance in showing that paraparesis, paraplegia, and quadriplegia occurred in the IOM patients with EP changes compared with the IOM group without EP changes. All studies were consistent in showing all occurrences of paraparesis, paraplegia, and quadriplegia in the IOM patients with EP changes, with no occurrences of paraparesis, paraplegia, and quadriplegia in patients without EP changes. In the Class I studies, 16%-40% of the IOM patients with EP changes developed postoperative-onset paraparesis, paraplegia, or quadriplegia. IOM is established as effective to predict an increased risk of the adverse outcomes of paraparesis, paraplegia, and quadriplegia in spinal surgery (4 Class I and 7 Class II studies). Surgeons and other members of the operating team should be alerted to the increased risk of severe adverse neurologic outcomes in patients with important IOM changes (Level A).


Assuntos
Potencial Evocado Motor/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Monitorização Intraoperatória/métodos , Medula Espinal/fisiologia , Coluna Vertebral/cirurgia , Medicina Baseada em Evidências , Humanos , Medula Espinal/cirurgia
7.
Clin Pharmacol Ther ; 89(2): 276-82, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21178989

RESUMO

Sixty treatment-seeking individuals with methamphetamine (MA) dependence entered a randomized, placebo-controlled, double-blind clinical trial of oral dextroamphetamine (d-AMP) as a replacement therapy for MA dependence. The subjects took 60 mg sustained-release d-AMP for 8 weeks, during which time they received eight 50-min sessions of individual psychotherapy. Adverse events and urine toxicology for MA were assessed two times a week. There were no serious adverse events. Urine samples containing <1,000 ng/ml of MA were classified as negative for MA. The MA-negative scores in the d-AMP group (3.1 ± SD 4.6) were no higher than those in the placebo group (3.3 ± SD 5.3; P > 0.05). However, withdrawal and craving scores were significantly lower in the d-AMP group (P < 0.05 for both). Although subjects taking d-AMP did not reduce their use of MA, the significant reductions observed in withdrawal and craving scores in this group support the need for further exploration of d-AMP as a pharmacologic intervention for MA dependence, possibly at higher doses.


Assuntos
Dextroanfetamina/administração & dosagem , Metanfetamina/efeitos adversos , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Preparações de Ação Retardada , Dextroanfetamina/efeitos adversos , Método Duplo-Cego , Feminino , Humanos , Masculino , Adesão à Medicação
8.
Clin Pharmacol Ther ; 88(4): 461-3, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20856245

RESUMO

In this issue, Larriviere and colleagues discuss the emerging use of drugs to enhance cognitive function. Several cautions they raise warrant amplification. People have tried to pharmacologically improve cognitive function for millennia, but Larriviere and colleagues postulate that new, more effective drugs will lead to the emergence of  "cosmetic neurology." The ethics of using drugs to improve performance, as opposed to treating disease or restoring normal function, are far from settled.


Assuntos
Estimulantes do Sistema Nervoso Central/uso terapêutico , Cognição , Ética Clínica , Nootrópicos/uso terapêutico , Estimulantes do Sistema Nervoso Central/administração & dosagem , Estimulantes do Sistema Nervoso Central/efeitos adversos , Humanos , Nootrópicos/administração & dosagem , Nootrópicos/efeitos adversos
9.
Br J Sports Med ; 43(11): 832-5, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18981044

RESUMO

OBJECTIVE: L-methamphetamine (the non-abused isomer of methamphetamine) is banned in athletic competition because it may improve athletic performance, but there are no studies assessing its effects on performance. In the United States L-methamphetamine is formulated in the non-prescription Vick's Vapor Inhaler (VVI) nasal decongestant. VVIs sold elsewhere (we used ones from the UK) contain similar inactive ingredients (menthol, camphor and Siberian pine oil) but no L-methamphetamine. This study tested the effects of inhaled L-methamphetamine delivered from a widely available non-prescription product on athletic performance. DESIGN: In a 2-session double-blind placebo-controlled study 12 participants (ages 14-17) were dosed with 4 (session 1) and 12 (session 2) inhalations from VVIs with (USA) or without (UK) L-methamphetamine and then performed two 20 minute rides on a stationary bike with rides separated by a 30 minute rest. OUTCOME MEASURE: The main outcome measure was miles travelled during each 20 minute ride. Secondary outcome measures included postride urine toxicology; heart rate and blood pressure before, 1, 5 and 10 minutes postride; energy, performance, endurance, and ability to breathe; and VVI preference. Data were analysed using Excel statistical macros. RESULTS: After approximately 16 microg L-methamphetamine distance travelled was 5.26 (SD 0.53) miles vs 5.30 (0.55) with placebo; p = 0.81. After approximately 48 microg L-methamphetamine distance travelled was 5.30 (0.51) vs 5.35 (0.43) with placebo; p = 0.85. The approximately 16 microg dose increased systolic blood pressure from 72.6 (4.3) to 79.6 (6.6) mm Hg (p = 0.03) at 5 minutes postride but there were no other differences in outcomes. CONCLUSIONS: Modest doses of inhaled L-methamphetamine probably do not improve athletic performance but do minimally raise diastolic blood pressure.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Metanfetamina/farmacologia , Descongestionantes Nasais/farmacologia , Medicamentos sem Prescrição/farmacologia , Administração por Inalação , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Combinação de Medicamentos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Metanfetamina/administração & dosagem , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Terpenos/administração & dosagem , Terpenos/farmacologia
10.
Clin Radiol ; 63(6): 681-7, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18455560

RESUMO

AIM: To investigate the presence of fatty infiltrate in the cervical extensor musculature in patients with insidious-onset neck pain to better understand the possible pathophysiology underlying such changes in chronic whiplash-associated disorders (WAD). MATERIALS AND METHODS: A sample of convenience of 23 women with persistent insidious-onset neck pain (mean age 29.2+/-6.9 years) was recruited for the study. Magnetic resonance imaging (MRI) was used to quantify fatty infiltration in the cervical extensor musculature. Quantitative Sensory Testing (QST; pressure and thermal pain thresholds) was performed as sensory features are present in chronic whiplash. Self-reported pain and disability, as well as psychological distress, were measured using the Neck Disability Index (NDI) and the General Health Questionnaire-28 (GHQ-28), respectively. RESULTS: Measures were compared with those of a previous dataset of chronic whiplash patients (n=79, mean age 29.7+/-7.8 years). Using a classification tree, insidious-onset neck pain was clearly identified from whiplash (p<0.001), based on the presence of MRI fatty infiltrate in the cervical extensor musculature (0/102 individuals) and altered temperature thresholds (cold; 3/102 individuals). CONCLUSION: Fatty infiltrates in the cervical extensor musculature and widespread hyperalgesia were not features of the insidious-onset neck pain group in this study; whereas these features have been identified in patients with chronic WAD. This novel finding may enable a better understanding of the underlying pathophysiological processes in patients with chronic whiplash.


Assuntos
Tecido Adiposo/patologia , Músculos do Pescoço/patologia , Cervicalgia/patologia , Traumatismos em Chicotada/patologia , Adolescente , Adulto , Vértebras Cervicais/patologia , Doença Crônica , Feminino , Humanos , Hiperalgesia/etiologia , Hiperalgesia/patologia , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Cervicalgia/complicações , Limiar da Dor , Estresse Psicológico/etiologia , Traumatismos em Chicotada/complicações
12.
Equine Vet J ; 38(5): 461-6, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16986608

RESUMO

REASONS FOR PERFORMING STUDY: Obtaining magnetic resonance images of the inner hoof wall tissue at the microscopic level would enable early accurate diagnosis of laminitis and therefore more effective therapy. OBJECTIVES: To optimise magnetic resonance imaging (MRI) parameters in order to obtain the highest possible resolution of the structures beneath the equine hoof wall. METHODS: Magnetic resonance microscopy (MRM) was performed in front feet from 6 cadaver horses using T2-weighted fast spin echo (FSE-T2), and T1-weighted gradient echo (GRE-T1) sequences. RESULTS: In T2 weighted FSE images most of the stratum medium showed no signal, however the coronary, terminal and sole papillae were visible. The stratum lamellatum was clearly visible and primary epidermal lamellae could be differentiated from dermal lamellae. CONCLUSION: Most structures beneath the hoof wall were differentiated. Conventional scanners for diagnostic MRI in horses are low or high field. However this study used ultra-high field scanners currently not available for clinical use. Signal-to-noise ratio (S/N) increases as a function of field strength. An increase of spatial resolution of the image results in a decreased S/N. S/N can also be improved with better coils and the resolution of high field MRI scanners will increase as technology develops and surface array coils become more readily available. POTENTIAL RELEVANCE: Although MR images with microscopic resolution were obtained ex vivo, this study demonstrates the potential for detection of lamellar pathology as it occurs. Early recognition of the development of laminitis to instigate effective therapy at an earlier stage and may improve the outcome for laminitic horses. Clinical MR is now readily available at 3 T, while 4 T, 7 T and 9 T systems are being used for human whole body applications.


Assuntos
Casco e Garras/anatomia & histologia , Casco e Garras/ultraestrutura , Cavalos/anatomia & histologia , Coxeadura Animal/diagnóstico , Imageamento por Ressonância Magnética/veterinária , Matadouros , Animais , Membro Anterior/anatomia & histologia , Casco e Garras/patologia , Coxeadura Animal/patologia , Imageamento por Ressonância Magnética/métodos , Sensibilidade e Especificidade
13.
Arch Dis Child ; 91(2): 164-8, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16308411

RESUMO

AIMS: To compare two treatments in common usage for children with atopic eczema: "wet wrap" bandages versus conventional topically applied ointments. METHODS: A total of 50 children (age 4-27 months) with moderate to severe eczema were randomised to one or other treatment. Two research nurses supervised the study. The first gave advice and support, and the second, blinded to the treatment modality being used, scored the change in eczema severity over a period of four weeks using the SCORAD eczema severity scale. RESULTS: Both treatments gave a benefit in overall SCORAD scores (mean change for wet wrap group was 53 to 24; for the conventional group, 41 to 17). There was no significant difference between the two groups in terms of overall improvement at four weeks or in the timescale of improvements. The amount of topical of topical steroid used was similar in both groups. The wet wrap group suffered significantly more skin infections requiring antibiotics. Carers reported that wet wraps were less easy to apply than conventional treatment.


Assuntos
Bandagens , Dermatite Atópica/terapia , Administração Cutânea , Anti-Inflamatórios/uso terapêutico , Pré-Escolar , Dermatite Atópica/tratamento farmacológico , Emolientes/uso terapêutico , Feminino , Glucocorticoides/uso terapêutico , Humanos , Hidrocortisona/uso terapêutico , Lactente , Masculino , Índice de Gravidade de Doença , Método Simples-Cego , Resultado do Tratamento , Água
14.
Orbit ; 24(4): 219-25, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16354629

RESUMO

INTRODUCTION: High-density porous polyethylene (Medpor) enophthalmic implants are used in patients with the sunken socket syndrome to augment the orbital volume. We have used them to improve enophthalmos and hypoglobus in the repair of large long-standing orbital floor fractures. This is the first report of enophthalmic wedge implants being used in seeing eyes to improve function and cosmesis. MATERIALS AND METHODS: Four patients had large long-standing orbital floor fractures with subsequent enlargement/expansion of the orbital volume. Indications for surgical intervention were enophthalmos (> 2 mm), hypoglobus (> 2 mm) and diplopia in primary position and downgaze. A transconjunctival approach was used to access the orbital floor and a Medpor enophthalmic wedge implant was placed postero-inferiorly to the globe and periosteum. RESULTS: Patients were followed up for a minimum of 4 to 6 months post-operatively with no complications noted. All patients achieved a good cosmetic and functional result post-operatively with resolution of their enophthalmos and hypoglobus. Diplopia in primary position was corrected with only mild residual diplopia present in extreme up-gaze. CONCLUSION: We have found enophthalmic implants useful in the surgical repair of symptomatic long-standing orbital floor fractures.


Assuntos
Enoftalmia/cirurgia , Fraturas Orbitárias/cirurgia , Implantes Orbitários , Adulto , Idoso , Enoftalmia/etiologia , Feminino , Humanos , Masculino , Polietilenos , Resultado do Tratamento
15.
Clin Radiol ; 60(3): 355-63, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15710139

RESUMO

AIM: To establish a simple method to quantify muscle/fat constituents in cervical muscles of asymptomatic women using magnetic resonance imaging (MRI), and to determine whether there is an age effect within a defined age range. MATERIALS AND METHODS: MRI of the upper cervical spine was performed for 42 asymptomatic women aged 18-45 years. The muscle and fat signal intensities on axial spin echo T1-weighted images were quantitatively classified by taking a ratio of the pixel intensity profiles of muscle against those of intermuscular fat for the rectus capitis posterior major and minor and inferior obliquus capitis muscles bilaterally. Inter- and intra-examiner agreement was scrutinized. RESULTS: The average relative values of fat within the upper cervical musculature compared with intermuscular fat indicated that there were only slight variations in indices between the three sets of muscles. There was no significant correlation between age and fat indices. There were significant differences for the relative fat within the muscle compared with intermuscular fat and body mass index for the right rectus capitis posterior major and right and left inferior obliquus capitis muscles (p=0.032). Intraclass correlation coefficients for intraobserver agreement ranged from 0.94 to 0.98. Inter-rater agreement of the measurements ranged from 0.75 to 0.97. CONCLUSION: A quantitative measure of muscle/fat constituents has been developed, and results of this study indicate that relative fatty infiltration is not a feature of age in the upper cervical extensor muscles of women aged 18-45 years.


Assuntos
Tecido Adiposo/anatomia & histologia , Imageamento por Ressonância Magnética , Músculo Esquelético/anatomia & histologia , Adolescente , Adulto , Envelhecimento/fisiologia , Análise de Variância , Vértebras Cervicais , Feminino , Humanos , Pessoa de Meia-Idade
20.
Phys Med Biol ; 47(11): 1881-90, 2002 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-12108773

RESUMO

Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acrylate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo readout with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found to be negligible under the prevailing experimental conditions. The usefulness of MT imaging was assessed by computing the dose resolution obtained with this technique. We found a low value of dose resolution over a wide range of doses could be obtained with a single experiment. This is an advantage over multiple spin echo (MSE) experiments using a single echo spacing where an optimal dose resolution is achieved over only very limited ranges of doses. The results suggest MT imaging protocols may be developed into a useful tool for polymer gel dosimetry.


Assuntos
Géis , Magnetismo , Polímeros , Radiometria/instrumentação , Radiometria/métodos , Relação Dose-Resposta à Radiação , Imageamento por Ressonância Magnética/métodos , Água/química
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