cumulative dose
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Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 90
Author(s):  
Clément Devic ◽  
Johann Plagnard ◽  
Mélodie Munier

For technical and radioprotection reasons, it has become essential to develop new dosimetric tools adapted to the specificities of computed tomography (CT) to ensure precise and efficient dosimetry since the current standards are not suitable for clinical use and for new CT technological evolution. Thanks to its many advantages, plastic scintillating fibers (PSF) is a good candidate for more accurate and personalized real-time dosimetry in computed tomography, and the company Fibermetrix has developed a new device named IVISCAN® based on this technology. In this study, we evaluated performances of IVISCAN® and associated uncertainties in terms of dose-rate dependence, angular dependence, stability with cumulative dose, repeatability, energy dependence, length dependence, and special uniformity in reference and clinical computed tomography beam qualities. For repeatability, the standard deviation is less than 0.039%, and the absolute uncertainty of repeatability lies between 0.017% and 0.025%. The deviation between IVISCAN® and the reference regarding energy dependence is less than 1.88% in clinical use. Dose rate dependence results show a maximum deviation under ±2%. Angular dependence standard deviation σ is 0.8%, and the absolute uncertainty was 1.6%. We observed 1% of variation every 50 Gy steps up to a cumulative dose of 500 Gy. Probe response was found to be independent of the PSF length with a maximum deviation < 2.7% between the IVISCAN® probe and the 1 cm PSF probe. The presented results demonstrated that IVISCAN® performances are in accordance with metrology references and the international standard IEC61674 relative to dosemeters used in X-ray diagnostic imaging and then make it an ideal candidate for real-time dosimetry in CT applications.


2021 ◽  
pp. annrheumdis-2021-221650
Author(s):  
Zhenyu Zhong ◽  
Weiting Liao ◽  
Lingyu Dai ◽  
Xiaojie Feng ◽  
Guannan Su ◽  
...  

ObjectivesCorticosteroids remain the mainstay of treatment for rheumatic diseases but can cause hepatitis B virus (HBV) reactivation in patients with resolved HBV infection. Risk assessment and stratification are needed to guide the management of these patients before corticosteroid therapy.MethodsWe prospectively enrolled patients with negative hepatitis B surface antigen positive Anti-hepatitis B core status with or without corticosteroid use and determined corticosteroid exposure by calculating cumulative dose and time-weighted average daily dose of prednisone. The primary outcome was the time to a composite of HBV reactivation, hepatitis flare or severe hepatitis.ResultsAmong 1303 participants, the median of cumulative dose and time-weighted average dose of prednisone used in this cohort was 3000 mg (IQR: 300–6750 mg) and 15 mg/day (IQR: 10–20 mg/day), respectively. In multivariable analyses, cumulative dose showed inverted V-shaped relationship with primary events, which peaked at a cumulative dose of 1506 mg (HR: 3.72; 95% CI, 1.96 to 7.08). Quartiles of time-weighted average dose were independently associated with a monotonic increase in event risk (HR per quartile increase: 2.15; 95% CI, 1.56 to 2.98), reaching an HR of 49.48 (95% CI, 6.24 to 392.48) in the top quartile. The incidence of primary outcome was 16.67 per 100 person-years in the top quartile of time-weighted average dose (Q4>20 mg/day). Other quartiles all had an incidence of primary outcome less than 10 per 100 person-years.ConclusionPatients with time-weighted average prednisone dose greater than 20 mg/day would be classified as the high risk for HBV reactivation or hepatitis flare. Prophylactic Anti-HBV therapy may be needed for these high-risk patients.Trial registration numberChiCTR1900023955.


2021 ◽  
pp. 107815522110681
Author(s):  
Imen Toukabri Ben Mahmoud ◽  
Azza Ben Said ◽  
Souad Berguiga ◽  
Racha Houij ◽  
Ines Cherif ◽  
...  

Introduction Oxaliplatin utilized in colorectal neoplasms treatment could induce acute peripheral neuropathy (APN) which is a dreadful and frequent adverse event. The objective of this study is to estimate incidence of APN induced by oxaliplatin cumulative incidence in cancer patients colorectal and to describe the distribution of the APN incidence according to demographic and clinical characteristics, as well as according to oxaliplatin cumulative dose. Material and methods This is a prospective descriptive study which took place from June to December 2018 at the Salah Azaiz Institute, Tunis. Demographic data, clinical data and data on oxaliplatin administration were collected from patient interview, medical files and pharmaceutical databases. Results The APN (grade 1, grade 2 and grade 3) cumulative incidence during the period of six months of follow up was 86% (95% CI [0.7815–0.9132]). While 38.3% (95% CI [0.29–0.48]) of the patients had grade 2 or 3 neuropathy. The search for factors associated with the risk of grade 2 and 3 NAP revealed trend significant association with diabetes (adjusted RR = 5.7 (IC95% [0.9- 37.3]; p = 0.07). Moreover, there was significant association with oxaliplatin cumulative dose (≥421 mg/m2) to increase the risk of APN grade 2 and 3 (adjusted RR = 7.8; [2.7–22.7]; p = 0.0001). Furthermore, significant association with obesity to increase the risk of APN grade 2 and 3 (adjusted RR = 5.3 [1.1- 25.4]; p = 0.04) was found. Among the patients included, 31.1% experienced oxaliplatin dose reduction and in the majority of cases this reduction is due to neurotoxicity (90.9%). Conclusion The high incidence of oxaliplatin-induced APN remains an embarrassing and handicapping side effect. Our study has shown that oxaliplatin cumulative dose (≥421 mg/m2), diabetes and obesity are risk factor for the development of grade 2 and 3 APN.


2021 ◽  
Author(s):  
Boshra Elbaz ◽  
Hala Elmarsafawy ◽  
Wafaa Laimon

Abstract This study aims to determine the incidence, potential onset and clinical course of hypothyroidism following cardiac catheter (CC) in infants with congenital heart diseases (CHD) and to evaluate the predictors for hypothyroidism in this vulnerable group. This prospective study included 102 patients with CHD, aged ≤ 3 years who underwent CC. Thyroid function tests were assessed before CC, one day, one week, two weeks and four weeks after the procedure. 12% of the studied group showed hypothyroidism four weeks after CC. Univariate analysis revealed that the significant predictors of hypothyroidism following CC are aortic stenosis (RR=10.0 (1.49-66.99), P=0.018), duration of fluoroscopy (RR=1.12 (0.99-1.26), P=0.05), and total cumulative dose of iodinated contrast media (iCM) (RR=1.01 (1.003 -1.01), P=0.019). Multivariate analysis revealed that iCM cumulative dose was the only significant predictor of developing hypothyroidism (RR=1.00 (1.00-1.01), P=0.04). ROC curve analysis showed that the cut-off point of iCM dose for prediction of hypothyroidism evolution is 8.7 gm/kg (26.1 ml/kg), (sensitivity: 83.3%, specificity: 65.1%), while the cut-off point of fluoroscopy duration which predicts development of hypothyroidism is 24 minutes, (sensitivity: 83.3%, specificity: 65.9%). In a median follow-up duration of 20 months, acquired hypothyroidism after CC persists in 5% of this cohort. Conclusion: Exposure to higher dose of iCM and longer duration of fluoroscopy during CC are risk factors for evolution of hypothyroidism. We recommend assessment of thyroid profile 4 weeks after CC particularly in patients who received a dose of iCM higher than 8.7 gm/kg and/or exposed to fluoroscopy for more than 24 minutes.


Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6287
Author(s):  
Lea Beltzig ◽  
Björn Stratenwerth ◽  
Bernd Kaina

Temozolomide (TMZ), a first-line drug in glioma therapy, targets the tumor DNA at various sites. One of the DNA alkylation products is O6-methylguanine (O6MeG), which is, in the low dose range of TMZ, responsible for nearly all genotoxic and cytotoxic effects relevant for cancer therapy. There is, however, a dispute regarding whether the TMZ concentration in the tumor tissue in patients is sufficient to elicit a significant cytotoxic or cytostatic response. Although treatment with TMZ occurs repeatedly with daily doses (metronomic dose schedule) and in view of the short half-life of the drug it is unclear whether doses are accumulating. Here, we addressed the question whether repeated low doses elicit similar effects in glioblastoma cells than a high cumulative dose. We show that repeated treatments with a low dose of TMZ (5 × 5 µM) caused an accumulation of cytotoxicity through apoptosis, cytostasis through cellular senescence, and DNA double-strand breaks, which was similar to the responses induced by a single cumulative dose of 25 µM TMZ. This finding, together with the previously reported linear dose–response curves, support the notion that TMZ is able to trigger a significant cytotoxic and cytostatic effect in vivo if the low-dose metronomic schedule is applied.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jee Hee Yoon ◽  
Seo-Yeon Ahn ◽  
Sung-Hoon Jung ◽  
Je-Jung Lee ◽  
Wonsuk Choi ◽  
...  

Multiple myeloma (MM) is the second most common hematologic malignancy and requires long-term and high-dose corticosteroid-based chemotherapy. The aim of this study was to investigate the prevalence and clinical predictors of corticosteroid-associated adrenal insufficiency (AI) in patients with MM receiving long-term chemotherapy. This retrospective study included patients with MM who were administered corticosteroid-based chemotherapy and underwent a rapid adrenocorticotropic hormone (ACTH) stimulation test between 2005 and 2018. AI was determined by a peak cortisol value < 18  μg/dL after ACTH stimulation. Demographic, clinical, and laboratory parameters were evaluated, and the prevalence and clinical risk factors of AI were examined. Of 282 patients with MM who received corticosteroid-based chemotherapy, 142 patients (50.4%) were classified as having AI. There were no differences in age, sex, body mass index, comorbidities, and laboratory findings, including serum sodium levels between the AI and no-AI groups. In univariate analysis, the cumulative dose of corticosteroid ( odds   ratio   OR = 0.99 , 95% confidence interval (CI) 0.98–0.99; P = 0.020 ) and megestrol acetate use ( OR = 2.63 , 95% CI 1.48–4.67; P = 0.001 ) were associated with the occurrence of AI. Cumulative duration and cumulative dose per duration of corticosteroid use were not associated with the occurrence of AI. However, in the multivariate analysis, only megestrol acetate use was associated with an increased risk of AI ( OR = 2.54 , 95% CI 1.41–4.60; P = 0.002 ). Approximately 95.8% of patients with AI had suspicious symptoms or signs of AI. Although clinical symptoms and signs are usually nonspecific, symptomatic patients with MM receiving long-term corticosteroid therapy have sufficient potential for developing AI, particularly when receiving megestrol acetate. These findings can help alert clinicians to consider adrenal suppression following corticosteroid-based chemotherapy in patients with MM.


2021 ◽  
Vol 12 ◽  
Author(s):  
Juan Lei ◽  
Aiting Liu ◽  
Yujia Ma ◽  
Guangzi Shi ◽  
Feng Han ◽  
...  

Background and Purpose: Breast cancer survivors have an increased cardiovascular risk, and vascular calcification is the pathological basis of cardiovascular disease. Some factors that affect the progression of thoracic aortic calcification (TAC) in survivors are unclear, and this study aims to explore the relationship between dexamethasone or radiotherapy and the progression of TAC in survivors.Materials and Methods: This study included 189 female patients with breast cancer, and they were divided into the progression and non-progression TAC groups. Radiation or dexamethasone doses, and related laboratory parameters were collected.Results: The cumulative dose of dexamethasone was higher [40 (10–180) mg versus 180 (80–270) mg, p &lt; 0.001], and the cycle was longer [4 (1–6) cycles versus 6 (4–8) cycles, p &lt; 0.001] in the non-progression TAC group. The cumulative dose (r = −0.303, p &lt; 0.001) and cycle (r = −0.357, p &lt; 0.001) of dexamethasone were negatively correlated with the level of increased TAC Agatston scores in survivors. Logistic regression analysis showed that dexamethasone was a protective factor for the progression of TAC (p = 0.029, odds ratio = 0.263, 95% confidence interval = 0.08–0.872). However, there wasn’t significant relationship between radiotherapy, radiation dose, follow-up time and the progression of TAC (all p &gt; 0.05). In addition, aorta volume was positively correlated with the level of increased TAC Agatston scores in intensity modulated radiation therapy (r = 0.460, p &lt; 0.001).Conclusion: Dexamethasone is associated with a lower risk of the progression of TAC in breast cancer survivors, and there’s no correlation between radiotherapy and progression of TAC, but the aorta volume may be a predictor of the severity of progression of TAC.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jung-Hyun Park ◽  
Min-Jeong Kwoen ◽  
Jae-Ryun Lee ◽  
Keun-Suh Kim ◽  
Hyo-Jung Lee ◽  
...  

BackgroundA causal relationship of bisphosphonate (BP) exposure with osteonecrosis of the jaw (ONJ) has been reported; however, a definite dose-dependent risk remains to be elucidated beyond current vague recommendations of 4-year oral BP for ONJ risk increase.ObjectiveTo identify the effect of bisphosphonate cumulative dose on ONJ development in women with osteoporosis.MethodsA retrospective cohort study was designed using the National Health Insurance Service—National Health Screening database of Korea. Females over the age of 50 were diagnosed with osteoporosis based on the International Classification of Diseases 10th revision (ICD-10) codes (M80, M81, and M82) with bisphosphonate prescriptions. The cumulative dose of bisphosphonate was calculated using defined daily doses (DDD) to provide an accurate BP cumulative effect on ONJ occurrence. Osteonecrosis of the jaw was identified using both ICD-10 codes and related procedure codes. The incidence rates of ONJ and hazard ratios were estimated according to the bisphosphonate cumulative dose.ResultsAmong 74,491 included subjects, 190 cases of ONJ were identified. The incidence rate substantially increased after BP cumulative dose over 1 year (25.75 for DDD &lt; 365, which increased to 53.43 for 365 ≤ DDD &lt; 730). Compared to subjects with a cumulative dose of DDD &lt; 365, subjects with a cumulative dose of 365 ≤ DDD &lt; 730 had 2.36-fold hazard for developing ONJ (p &lt; 0.001).ConclusionA bisphosphonate cumulative dose of more than 1 year had an increased risk of ONJ development. A gradual, but not sudden, dose-dependent increase in ONJ risk with BP exposure needs to be considered in providing the optimal BP treatment duration.


2021 ◽  
Vol 4 (12) ◽  
pp. e2136697
Author(s):  
Kyla A. McKay ◽  
Fredrik Piehl ◽  
Simon Englund ◽  
Anna He ◽  
Annette Langer-Gould ◽  
...  

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