RESUMO
The purpose of this guideline is to provide a list of critical performance tests to assist the Qualified Medical Physicist (QMP) in establishing and maintaining a safe and effective quality assurance (QA) program. The performance tests on a linear accelerator (linac) should be selected to fit the clinical patterns of use of the accelerator and care should be given to perform tests which are relevant to detecting errors related to the specific use of the accelerator. Current recommendations for linac QA were reviewed to determine any changes required to those tests highlighted by the original report as well as considering new components of the treatment process that have become common since its publication. Recommendations are made on the acquisition of reference data, routine establishment of machine isocenter, basing performance tests on clinical use of the linac, working with vendors to establish QA tests and performing tests after maintenance and upgrades. The recommended tests proposed in this guideline were chosen based on consensus of the guideline's committee after assessing necessary changes from the previous report. The tests are grouped together by class of test (e.g., dosimetry, mechanical, etc.) and clinical parameter tested. Implementation notes are included for each test so that the QMP can understand the overall goal of each test. This guideline will assist the QMP in developing a comprehensive QA program for linacs in the external beam radiation therapy setting. The committee sought to prioritize tests by their implication on quality and patient safety. The QMP is ultimately responsible for implementing appropriate tests. In the spirit of the report from American Association of Physicists in Medicine Task Group 100, individual institutions are encouraged to analyze the risks involved in their own clinical practice and determine which performance tests are relevant in their own radiotherapy clinics.
Assuntos
Radiometria , Planejamento da Radioterapia Assistida por Computador , Humanos , Aceleradores de Partículas , Cintilografia , FísicaRESUMO
This is the first study of US adults to examine change in the prevalence of psychological burden (i.e., self-reported poor mental health days in the past 30 days, and ACEs recollections) before compared to after COVID-19 started. We analyzed the prevalence of self-reported poor mental health days, and ACEs recollections from 17 states using the Behavioral Risk Factor Surveillance System. Adjusted models identified an increase in prevalence from before compared to after COVID-19 onset in those married or partnered reporting 48% more poor mental health days in the past 30 days; persons of color reporting living with anyone with mental illness during childhood by 73% and reporting more ACEs by 35%; those employed or self-employed reporting childhood sexual abuse by 45%. This ecological-level analysis revealed population-level changes in psychological well-being reporting of U.S. adults from before compared to after the pandemic onset.
Assuntos
Experiências Adversas da Infância , COVID-19 , Transtornos Mentais , Adulto , Humanos , Saúde Mental , Prevalência , COVID-19/epidemiologia , Transtornos Mentais/epidemiologiaRESUMO
(1) Background: The Exradin W2 is a commercially available scintillator detector designed for reference and relative dosimetry in small fields. In this work, we investigated the performance of the W2 scintillator in a 10 MV flattening-filter-free photon beam and compared it to the performance of ion chambers designed for small field measurements. (2) Methods: We measured beam profiles and percent depth dose curves with each detector and investigated the linearity of each system based on dose per pulse (DPP) and pulse repetition frequency. (3) Results: We found excellent agreement between the W2 scintillator and the ion chambers for beam profiles and percent depth dose curves. Our results also showed that the two-voltage method of calculating the ion recombination correction factor was sufficient to correct for the ion recombination effect of ion chambers, even at the highest DPP. (4) Conclusions: These findings show that the W2 scintillator shows excellent agreement with ion chambers in high DPP conditions.
Assuntos
Fótons , Plásticos , Radiometria/métodosRESUMO
Cetuximab conjugated iron-oxide nanoparticles (cetuximab-IONPs) have shown both in-vitro and in-vivo anti-tumor efficacy against gliomas. The purpose of this pilot study was to evaluate the safety and potential efficacy of cetuximab-IONPs for treatment of spontaneously occurring intracranial gliomas in canines after convection-enhanced delivery (CED). The use of CED allowed for direct infusion of the cetuximab-IONPs both intratumorally and peritumorally avoiding the blood brain barrier (BBB) and limiting systemic effects. A total of eight dogs participated in the study and only two developed mild post-operative complications, which resolved with medical therapy. All canines underwent a single CED treatment of the cetuximab-IONPs over 3 days and did not receive any further adjuvant treatments. Volumetric analysis showed a median reduction in tumor size of 54.9% by MRI at 1-month (4-6 weeks) follow-up. Five dogs were euthanized due to recurrence of neurological signs other than seizures, two due to recurrent seizures, and one dog died in his sleep. Median survival time after surgery was 248 days (mean 367 days).
Assuntos
Antineoplásicos Imunológicos/administração & dosagem , Neoplasias Encefálicas/veterinária , Cetuximab/administração & dosagem , Doenças do Cão/tratamento farmacológico , Glioma/veterinária , Nanopartículas de Magnetita/administração & dosagem , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Encéfalo/cirurgia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/cirurgia , Convecção , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/cirurgia , Cães , Feminino , Seguimentos , Glioma/diagnóstico por imagem , Glioma/tratamento farmacológico , Glioma/cirurgia , Bombas de Infusão Implantáveis , Masculino , Resultado do Tratamento , Carga TumoralRESUMO
A dog with lameness, stifle effusion, and osteophytes, but in which the stifle retained stability for 10 months after the onset of lameness, was evaluated with 3T magnetic resonance imaging (MRI). Imaging revealed a tear in the caudal meniscotibial ligament of the medial meniscus. Arthroscopy findings correlated well with MRI and a partial meniscectomy was subsequently carried out, without any surgery to stabilize the stifle, and lameness resolved.
Diagnostic par imagerie à résonance magnétique et traitement arthroscopique d'une blessure du ménisque médial chez un chien ayant un grasset stable à la palpation. Un chien présentant de la boiterie, de l'effusion du grasset et des ostéophytes, mais pour lequel le grasset a conservé de la stabilité pendant 10 mois après l'apparition de la boiterie, a été évalué à l'aide de l'imagerie à résonance magnétique (IRM) 3T. L'IRM a révélé une déchirure dans le ligament méniscotibial caudal du ménisque médial. Les résultats de l'arthroscopie présentaient une bonne corrélation avec l'IRM et une méniscectomie partielle a ensuite été réalisée sans chirurgie pour stabiliser le grasset et la boiterie a été résolue.(Traduit par Isabelle Vallières).
Assuntos
Artroscopia/veterinária , Cães/lesões , Cães/cirurgia , Lesões do Menisco Tibial/veterinária , Animais , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/veterinária , Imageamento por Ressonância Magnética/veterinária , Masculino , Joelho de Quadrúpedes/diagnóstico por imagem , Joelho de Quadrúpedes/lesões , Lesões do Menisco Tibial/diagnóstico por imagem , Lesões do Menisco Tibial/cirurgiaRESUMO
OBJECTIVE: To describe the clinical details, surgery, postoperative imaging, and short to mid-term outcome after cranioplasty with titanium mesh in dogs with large skull tumors. STUDY DESIGN: Case series. ANIMALS: Client-owned dogs with skull tumors (n=5). METHODS: All tumors were removed via craniectomy and a sheet of titanium mesh was contoured to reconstruct the calvarial defect and sutured to surrounding musculature. RESULTS: Four dogs had multilobular tumors of bone and 1 dog had a soft tissue sarcoma invading the cranial vault. Neurologic examination was unchanged or improved postoperative, a good cosmetic appearance was achieved, and no complications were noted at 2 weeks postoperative. Late postoperative computed tomography (CT) in 2 dogs and magnetic resonance (MR) imaging in 1 dog confirmed the presence of the titanium mesh without migration. There was no interference of the mesh with image interpretation and definitive radiation therapy was pursued in 1 dog without complication. Late follow-up reported 2 dogs euthanatized; at 44 weeks postoperative due to tumor re-growth; at 12 weeks postoperative for hemoabdomen, respectively. One dog drowned at 40 weeks postoperative, 1 dog was lost to follow-up, and 1 dog is alive at 83 weeks postoperative free of clinical signs. CONCLUSIONS: Titanium mesh is suitable for cranioplasty based on its strength, biocompatibility, and excellent handling characteristics. It does not interfere with acquisition or interpretation of CT or MR images, thereby allowing postoperative imaging for ongoing assessment.
Assuntos
Craniotomia/veterinária , Doenças do Cão/cirurgia , Neoplasias Cranianas/veterinária , Telas Cirúrgicas/veterinária , Animais , Doenças do Cão/diagnóstico por imagem , Cães , Feminino , Imageamento por Ressonância Magnética , Masculino , Próteses e Implantes , Procedimentos de Cirurgia Plástica , Neoplasias Cranianas/cirurgia , Titânio , Tomografia Computadorizada por Raios X/métodos , Resultado do TratamentoRESUMO
Magnetic resonance imaging (MRI) is a common test for dogs with suspected intradural spinal cord lesions, however studies on diagnostic performance for this test are lacking. Objectives of this multi-institutional, retrospective, case-control study were to estimate sensitivity and specificity of MRI for (1) distinguishing between histopathologically confirmed intradural spinal cord disease versus degenerative myelopathy in dogs, (2) categorizing intradural spinal cord diseases as neoplastic, inflammatory, or vascular; and (3) determining tumor type within the etiologic category of neoplasia. Additional aims were to (1) determine whether knowledge of clinical data affects sensitivity and specificity of MRI diagnoses; and (2) report interrater agreement for MRI classification of intradural spinal lesions. Cases were recruited from participating hospital databases over a 7-year period. Three reviewers independently evaluated each MRI study prior to and after provision of clinical information. A total of 87 cases were sampled (17 degenerative myelopathy, 53 neoplasia, nine inflammatory, and eight vascular). Magnetic resonance imaging had excellent (>97.6%) sensitivity for diagnosis of intradural spinal cord lesions but specificity varied before and after provision of clinical data (68.6% vs. 82.4%, P = 0.023). Magnetic resonance imaging had good sensitivity (86.8%) and moderate specificity (64.7-72.5%) for diagnosing neoplasia. Sensitivity was lower for classifying inflammatory lesions but improved with provision of clinical data (48.1% vs. 81.5%, P = 0.015). Magnetic resonance imaging was insensitive for diagnosing vascular lesions (25.0%). Interrater agreement was very good for correctly diagnosing dogs with intradural lesions (ĸ = 0.882-0.833), and good (ĸ = 0.726-0.671) for diagnosing dogs with neoplasia.
Assuntos
Doenças do Cão/diagnóstico , Mielite/veterinária , Neoplasias da Medula Espinal/veterinária , Doenças Vasculares da Medula Espinal/veterinária , Animais , Estudos de Casos e Controles , Doenças do Cão/diagnóstico por imagem , Cães , Feminino , Imageamento por Ressonância Magnética , Masculino , Mielite/diagnóstico , Mielite/diagnóstico por imagem , Estudos Retrospectivos , Sensibilidade e Especificidade , Neoplasias da Medula Espinal/diagnóstico , Neoplasias da Medula Espinal/diagnóstico por imagem , Doenças Vasculares da Medula Espinal/diagnóstico , Doenças Vasculares da Medula Espinal/diagnóstico por imagemRESUMO
OBJECTIVE: To evaluate the effects of a new microfracture and ligament splitting procedure on ligament healing and to examine the usefulness of magnetic resonance (MR) imaging for monitoring ligament healing over time using a collagenase model of hind limb proximal suspensory desmitis. STUDY DESIGN: Experimental in vivo study. ANIMALS: Healthy adult horses (n=6). METHODS: Horses were free of lameness with normal hind limb proximal suspensory ligaments (PSL). The origin of both hind limb PSL was injected with collagenase and underwent MR imaging 2 weeks later, followed by the microfracture and ligament splitting procedure on 1 limb, with the opposite limb serving as the sham-operated control. Serial lameness and MR examinations were performed. Horses were euthanatized 210 days after surgery, the PSL harvested, and histology, biochemistry, and gene expression performed on both PSL. RESULTS: Collagenase lesions viewed on MR images appeared similar to those seen clinically. Serial MR images demonstrated resolution of abnormal signal intensity and tissue formation in the microfracture sites within the third metatarsal bone. Treated limbs had histologic evidence of connective tissue appearing to originate from the small perforations and blending into the ligament but no statistical differences were identified. Gene expression for cartilage oligomeric matrix protein and decorin were significantly increased in treated compared to control limbs. CONCLUSION: The microfracture and ligament splitting procedure did incite a tissue response but further clinical investigation is necessary to determine if this tissue remodeling at the bone-ligament interface translates to improved clinical outcome. MR imaging may be useful to follow healing in horses with hind limb proximal suspensory desmitis.
Assuntos
Membro Posterior/cirurgia , Cavalos/cirurgia , Ligamentos/cirurgia , Imageamento por Ressonância Magnética/veterinária , Cirurgia Veterinária/métodos , Animais , Feminino , Membro Posterior/patologia , Ligamentos/patologia , Imageamento por Ressonância Magnética/métodos , MasculinoRESUMO
A 9-year-old spayed female Scottish terrier presented with an 8-day history of progressive paraparesis. Neurological examination suggested a painful T3-L3 myelopathy. Multifocal uniform contrast-enhancing masses involving the vertebral bodies, pedicles, laminae, and spinous processes of two vertebrae and compressing the spinal cord were present on MRI. Fluoroscopic-guided fine needle aspiration of one of the vertebral lesions revealed a predominantly lymphoblastic population of cells compatible with a diagnosis of lymphoma. To the authors' knowledge, this represents the first published case of canine lymphoma with vertebral involvement, characterized with MRI.
Assuntos
Doenças do Cão/diagnóstico por imagem , Linfoma/veterinária , Paraparesia/veterinária , Doenças da Coluna Vertebral/veterinária , Animais , Biópsia por Agulha Fina/veterinária , Cães , Feminino , Georgia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/patologia , Linfoma/diagnóstico por imagem , Imageamento por Ressonância Magnética/veterinária , Paraparesia/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Medula Espinal/patologia , Doenças da Coluna Vertebral/diagnóstico por imagemRESUMO
An imaging report is a vital communication tool between a radiologist and clinician. In a field where in-person communication may not be readily available, it is imperative that the report clearly relays pertinent clinical information in a timely manner. The purpose of this observational study was to describe and compare opinions and expectations of small animal general practitioners, veterinary specialists, and veterinary radiologists regarding the imaging report. Online surveys were distributed, and data were collected from 202 veterinary clinicians and 123 veterinary radiologists. The majority (89%) of clinicians were satisfied with their imaging reports and stated that they read the radiology report as soon as it was available (92%). Just less than half (48%) of clinicians indicated it was standard of care that a board-certified veterinary radiologist read all imaging studies. Radiologists and clinicians agreed that a clinical history (98% and 94%, respectively) and clinical question (82% and 68%, respectively) were needed to generate a good radiology report. Fifty-five percent to 70% of clinicians prefer red bulleted reports, which included incidental findings (96%); while radiologists slightly favored prose reporting (37-46%). Clinicians found it helpful when additional imaging (86%), medical (71%), and surgical recommendations (73%) were made. About one-third of specialists who had been in practice for >11 years thought they were better able to interpret imaging for their own specialty than the radiologist. Clinicians voiced discontentment with reports that were not completed in a timely manner or did not give a prioritized differential list. Further studies are warranted to provide a more in-depth evaluation of veterinary radiology reporting structure and style.
Assuntos
Atitude do Pessoal de Saúde , Diagnóstico por Imagem/veterinária , Radiologia , Médicos Veterinários/psicologia , Diagnóstico por Imagem/psicologia , Estudos Observacionais como Assunto , Estudos Prospectivos , Radiologia/estatística & dados numéricos , Inquéritos e Questionários , Estados UnidosRESUMO
A German shepherd puppy presented for evaluation of a suspected arteriovenous fistula on the distal aspect of the right pelvic limb. Radiographs demonstrated expansion and resorption of the tarsal and metatarsal bones, and ultrasound detected a vascular abnormality. Using computed tomographic angiography, a complex arteriovenous malformation (AVM) involving the distal tibia, tarsus, and the metatarsus and an osteochondritis dissecans (OCD) lesion of the talus were identified. Based on these findings, therapeutic limb amputation was performed. Fluoroscopic angiography, vascular casting, and dissection were then used to further characterize features of this previously unreported AVM with concurrent bony lesions and OCD.
Assuntos
Malformações Arteriovenosas/veterinária , Cães/anormalidades , Membro Posterior/anormalidades , Animais , Malformações Arteriovenosas/diagnóstico por imagem , Feminino , Fluoroscopia/veterinária , Membro Posterior/diagnóstico por imagem , Osteocondrite Dissecante/diagnóstico por imagem , Osteocondrite Dissecante/veterinária , Ossos do Tarso/diagnóstico por imagem , Ossos do Tarso/patologia , Tíbia/diagnóstico por imagem , Tíbia/patologia , Tomografia por Raios X/veterináriaRESUMO
A 23-yr-old female spayed bobcat (Lynx rufus) presented with a 1-wk history of hypersalivation. On examination, the right mandible was markedly thickened, the right mandibular dental arcade was missing, and the oral mucosa over the right mandible was ulcerated and thickened. Skull radiographs and fine needle aspirate cytology were supportive of squamous cell carcinoma. The bobcat was euthanized as a result of its poor prognosis. Necropsy confirmed a diagnosis of oral squamous cell carcinoma of the mandible. To the authors' knowledge, this is the first report of oral squamous cell carcinoma in a bobcat.
Assuntos
Carcinoma de Células Escamosas/veterinária , Lynx , Neoplasias Mandibulares/veterinária , Animais , Animais de Zoológico , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/patologia , Neoplasias Mandibulares/diagnóstico , Neoplasias Mandibulares/patologiaRESUMO
A 10-yr-old female spayed bobcat (Felis rufus) presented with a 3-day history of lethargy, anorexia, and two episodes of vomiting. An emergency field visit was scheduled to perform abdominal radiography and ultrasonography. The bobcat was assessed to be approximately 5-10% dehydrated, on the basis of decreased skin turgor and tacky mucous membranes. Free peritoneal gas, reduced abdominal serosal detail, and an abnormal-appearing right-sided intestinal segment were identified in the abdominal radiographs. However, the emergency field clinicians were not knowledgeable of these abnormalities, because the radiographs could not be processed in the field. During an initial complete abdominal ultrasound evaluation, a nondependent hyperechoic interface with reverberation artifact suggestive of intestinal or free gas and focal intestinal changes indicative of marked enteritis or peritonitis were identified. Free peritoneal fluid was not present on initial examination. In a focused abdominal sonography for trauma (FAST) scan, made after subcutaneous fluid administration, a small volume of anechoic free fluid was present in the peritoneal space. With ultrasound guidance, the fluid was aspirated and appeared grossly turbid. This fluid was subsequently confirmed as septic suppurative effusion, secondary to a foreign body-associated intestinal perforation. The use of a FAST scan is well described in human medicine, and to a limited degree in veterinary literature. This case represents a novel application of FAST scanning in an emergency field setting in a nontraumatized patient. This case report illustrates the utility of the FAST scan in yielding critical clinical information after fluid resuscitation in a zoological setting.
Assuntos
Corpos Estranhos/veterinária , Perfuração Intestinal/veterinária , Jejuno/patologia , Lynx , Animais , Animais de Zoológico , Feminino , Corpos Estranhos/diagnóstico por imagem , Corpos Estranhos/patologia , Corpos Estranhos/cirurgia , Perfuração Intestinal/diagnóstico por imagem , Perfuração Intestinal/patologia , Perfuração Intestinal/cirurgia , Jejuno/diagnóstico por imagem , UltrassonografiaRESUMO
A 25-year-old, female eclectus parrot (Eclectus roratus) presented for dyspnea 3 weeks after anesthesia and surgery for egg yolk coelomitis. Radiography, computed tomography, and tracheoscopy revealed multiple tracheal strictures spanning a length of 2.6 cm in the mid to distal trachea. Histopathologic examination revealed mild fibrosis, inflammation, and hyperplasia consistent with acquired tracheal strictures. Tracheal resection was not considered possible because of the length of the affected trachea. The strictures were resected endoscopically, and repeated balloon dilation under fluoroscopic guidance over the course of 10 months resulted in immediate but unsustained improvement. Computed tomography was used to measure the stenotic area. A 4 × 36-mm, custom-made, nitinol wire stent was inserted into the trachea under fluoroscopic guidance. After stent placement, intermittent episodes of mild to moderate dyspnea continued, and these responded to nebulization with a combination of saline, acetylcysteine, and dexamethasone. Multiple attempts to wean the patient off nebulization therapy and to switch to a corticosteroid-free combination were unsuccessful. The parrot eventually developed complications, was euthanatized, and necropsy was performed. Histologically, the tracheal mucosa had widespread erosion to ulceration, with accumulation of intraluminal exudate and bacteria, severe degeneration of skeletal muscle and tracheal rings, prominent fibrosis, and mild to moderate, submucosal inflammation. Clinicopathologic findings in this case suggested tracheomalacia, which has not been previously described in birds. Custom-made tracheal stents can be used for severe tracheal stenosis in birds when tracheal resection and anastomosis is not possible. Complications of tracheal stent placement in birds may include tracheitis and tracheomalacia. To our knowledge, this is the first report of tracheal stent placement in an avian species.
Assuntos
Ligas , Doenças das Aves/cirurgia , Papagaios , Stents , Estenose Traqueal/veterinária , Animais , Doenças das Aves/patologia , Feminino , Estenose Traqueal/patologia , Estenose Traqueal/cirurgia , Traqueomalácia/diagnóstico , Traqueomalácia/patologia , Traqueomalácia/veterináriaRESUMO
Magnetic resonance (MR) imaging characteristics are commonly used to help predict intracranial disease categories in dogs, however, few large studies have objectively evaluated these characteristics. The purpose of this retrospective study was to evaluate MR characteristics that have been used to differentiate neoplastic, inflammatory, and vascular intracranial diseases in a large, multi-institutional population of dogs. Medical records from three veterinary teaching hospitals were searched over a 6-year period for dogs that had diagnostic quality brain MR scans and histologically confirmed intracranial disease. Three examiners who were unaware of histologic diagnosis independently evaluated 19 MR lesion characteristics totaling 57 possible responses. A total of 75 dogs with histologically confirmed intracranial disease were included in analyses: 51 with neoplasia, 18 with inflammatory disease, and six with cerebrovascular disease. Only strong contrast enhancement was more common in neoplasia than other disease categories. A multivariable statistical model suggested that extra-axial origin, T2-FLAIR mixed intensity, and defined lesion margins were also predictive of neoplasia. Meningeal enhancement, irregular lesion shape, and multifocal location distinguished inflammatory diseases from the other disease categories. No MR characteristics distinguished vascular lesions and these appeared most similar to neoplasia. These results differed from a previous report describing seven MR characteristics that were predictive of neoplasia in dogs and cats. Findings from the current study indicated that the high performance of MR for diagnosing canine intracranial diseases might be due to evaluator recognition of combinations of MR characteristics vs. relying on any one MR characteristic alone.
Assuntos
Neoplasias Encefálicas/veterinária , Transtornos Cerebrovasculares/veterinária , Doenças do Cão/diagnóstico , Encefalite/veterinária , Imageamento por Ressonância Magnética/veterinária , Animais , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/etiologia , Transtornos Cerebrovasculares/diagnóstico , Transtornos Cerebrovasculares/etiologia , Meios de Contraste , Diagnóstico Diferencial , Doenças do Cão/etiologia , Cães , Encefalite/diagnóstico , Encefalite/etiologia , Feminino , Masculino , Estudos RetrospectivosRESUMO
A 12-year-old dachshund dog was presented for persistent hypercalcemia and hyperparathyroidism despite bilateral parathyroidectomy. Magnetic resonance imaging of the head, neck, and cranial mediastinum identified an increased number of cranial mediastinal lymph nodes with heterogeneous signal intensity. Hypercalcemia and hyperparathyroidism resolved after surgery to remove multiple cranial mediastinal lymph nodes, one of which contained presumed metastatic parathyroid tissue.
Adénocarcinome parathyroïdien métastatique fonctionnel chez un chien. Un chien Dachsund âgé de 12 ans a été présenté pour de l'hypercalcémie et de l'hyperparathyroïdie persistantes malgré une parathyroïdectomie bilatérale. Une imagerie par résonance magnétique de la tête, du cou et du médiastin crânien a identifié un nombre accru de ganglions lymphatiques médiastinaux avec une intensité hétérogène du signal. L'hypercalcémie et l'hyperparathyroïdie se sont résorbées après la chirurgie pour enlever les nombreux ganglions lymphatiques médiastinaux crâniens, dont l'un contenait du tissu parathyroïdien métastatique présumé.(Traduit par Isabelle Vallières).
Assuntos
Adenocarcinoma/veterinária , Doenças do Cão/patologia , Linfonodos/patologia , Neoplasias das Paratireoides/veterinária , Adenocarcinoma/patologia , Animais , Cães , Hipercalcemia/etiologia , Hipercalcemia/veterinária , Hiperparatireoidismo/etiologia , Hiperparatireoidismo/veterinária , Linfonodos/cirurgia , Metástase Linfática , Masculino , Neoplasias das Paratireoides/patologiaRESUMO
BACKGROUND: Dosimetry in ultra-high dose rate (UHDR) beamlines is significantly challenged by limitations in real-time monitoring and accurate measurement of beam output, beam parameters, and delivered doses using conventional radiation detectors, which exhibit dependencies in ultra-high dose-rate (UHDR) and high dose-per-pulse (DPP) beamline conditions. PURPOSE: In this study, we characterized the response of the Exradin W2 plastic scintillator (Standard Imaging, Inc.), a water-equivalent detector that provides measurements with a time resolution of 100 Hz, to determine its feasibility for use in UHDR electron beamlines. METHODS: The W2 scintillator was exposed to an UHDR electron beam with different beam parameters by varying the pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings of an electron UHDR linear accelerator system. The response of the W2 scintillator was evaluated as a function of the total integrated dose delivered, DPP, and mean and instantaneous dose rate. To account for detector radiation damage, the signal sensitivity (pC/Gy) of the W2 scintillator was measured and tracked as a function of dose history. RESULTS: The W2 scintillator demonstrated mean dose rate independence and linearity as a function of integrated dose and DPP for DPP ≤ 1.5 Gy (R2 > 0.99) and PRF ≤ 90 Hz. At DPP > 1.5 Gy, nonlinear behavior and signal saturation in the blue and green signals as a function of DPP, PRF, and integrated dose became apparent. In the absence of Cerenkov correction, the W2 scintillator exhibited PW dependence, even at DPP values <1.5 Gy, with a difference of up to 31% and 54% in the measured blue and green signal for PWs ranging from 0.5 to 3.6 µs. The change in signal sensitivity of the W2 scintillator as a function of accumulated dose was approximately 4%/kGy and 0.3%/kGy for the measured blue and green signal responses, respectively, as a function of integrated dose history. CONCLUSION: The Exradin W2 scintillator can provide output measurements that are both dose rate independent and linear in response if the DPP is kept ≤1.5 Gy (corresponding to a mean dose rate up to 290 Gy/s in the used system), as long as proper calibration is performed to account for PW and changes in signal sensitivity as a function of accumulated dose. For DPP > 1.5 Gy, the W2 scintillator's response becomes nonlinear, likely due to limitations in the electrometer related to the high signal intensity.
Assuntos
Elétrons , Contagem de Cintilação , Contagem de Cintilação/instrumentação , Dosagem Radioterapêutica , Radiometria/instrumentação , Radioterapia/instrumentação , Aceleradores de PartículasRESUMO
Ion chambers are required for calibration and reference dosimetry applications in radiation therapy (RT). However, exposure of ion chambers in ultra-high dose rate (UHDR) conditions pertinent to FLASH-RT leads to severe saturation and ion recombination, which limits their performance and usability. The purpose of this study was to comprehensively evaluate a set of commonly used commercially available ion chambers in RT, all with different design characteristics, and use this information to produce a prototype ion chamber with improved performance in UHDR conditions as a first step toward ion chambers specific for FLASH-RT. The Advanced Markus and Exradin A10, A26, and A20 ion chambers were evaluated. The chambers were placed in a water tank, at a depth of 2 cm, and exposed to an UHDR electron beam at different pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings on an IntraOp Mobetron. Ion chamber responses were investigated for the various beam parameter settings to isolate their dependence on integrated dose, mean dose rate and instantaneous dose rate, dose-per-pulse (DPP), and their design features such as chamber type, bias voltage, and collection volume. Furthermore, a thin parallel-plate (TPP) prototype ion chamber with reduced collector plate separation and volume was constructed and equally evaluated as the other chambers. The charge collection efficiency of the investigated ion chambers decreased with increasing DPP, whereas the mean dose rate did not affect the response of the chambers (± 1%). The dependence of the chamber response on DPP was found to be solely related to the total dose within the pulse, and not on mean dose rate, PW, or instantaneous dose rate within the ranges investigated. The polarity correction factor (Ppol ) values of the TPP prototype, A10, and Advanced Markus chambers were found to be independent of DPP and dose rate (± 2%), while the A20 and A26 chambers yielded significantly larger variations and dependencies under the same conditions. Ion chamber performance evaluated under different irradiation conditions of an UHDR electron beam revealed a strong dependence on DPP and a negligible dependence on the mean and instantaneous dose rates. These results suggest that modifications to ion chambers design to improve their usability in UHDR beamlines should focus on minimizing DPP effects, with emphasis on optimizing the electric field strength, through the construction of smaller electrode separation and larger bias voltages. This was confirmed through the production and evaluation of a prototype ion chamber specifically designed with these characteristics.
Assuntos
Elétrons , Radiometria , Radiometria/métodos , Calibragem , ÁguaRESUMO
Introduction: Despite the growing interest in "food as medicine," healthcare professionals have very limited exposure to nutrition as part of their training. Culinary medicine (CM), an evidence-based field integrating nutrition education with culinary knowledge and skills, offers one approach to fill this training gap. The American College of Lifestyle Medicine published a complimentary Culinary Medicine Curriculum (CMC) in 2019, and the objective of this study is to evaluate its reach and utilization, as well as to collect feedback from users. Methods: Individuals who downloaded the CMC prior to March 1, 2022 (N = 6,162) were emailed an invitation to participate in an online, cross-sectional survey. The survey included both multiple choice and free-text questions about whether CM sessions were conducted, if and how the CMC was used, if and how it was modified for use, and additional requested resources. Free-text responses were inductively coded, and quantitative data was summarized using descriptive statistics. Results: A total of 522 respondents provided consent, indicated that they had downloaded the curriculum, and completed the survey. Of the 522, 366 (70%) reported that they had not led or created any CM sessions. The top-reported reason for not leading a session was lack of time (29%). The remaining respondents who did create a CM session did so across various settings, including academic, clinical, coaching, and other settings, and a variety of professionals delivered the CMC sessions, including physicians (50%), registered dietitian nutritionists (30%), and chefs (25%). The majority of respondents (81%) modified the CMC in some way, with many using the curriculum for guidance or ideas only. Patient education materials (66%) and cooking technique instruction videos (59%) were among top requested resources. Discussion: The CMC is a versatile resource that can be successfully adapted for use across various settings and by various types of health professionals and practitioners. Future research should investigate whether training in CM results in improved health outcomes for patients/clients. The curriculum will continue to grow to address the needs of users by expanding to include more digital content such as curriculum videos and cooking technique videos.
RESUMO
A 13 yr old female spayed Labrador retriever presented for vulvar bleeding. Abdominal radiographs revealed a soft tissue mass in the ventral pelvic canal. A computed tomography (CT) exam and a CT vaginourethrogram localized the mass to the vagina, helped further characterize the mass, and aided in surgical planning. A total vaginectomy was performed and the histologic diagnosis was leiomyoma. Vaginal tumors make up 1.9-3% of all tumors. Seventy-three percent of vaginal tumors are benign, and 83% of those are leiomyomas. Leiomyomas often have a good long-term prognosis with surgical resection. The diagnostic investigation of this case report utilized a multimodal imaging approach to determine the extent and respectability of the vaginal mass. To the best of the authors' knowledge, this is the first report describing a CT vaginourethrogram.