Magnetron Sputtered CsPbCl3 Perovskite Detectors as Real-Time Dosimeters for Clinical Radiotherapy

The aim of this study is to investigate the feasibility of manufacturing thin real-time relative dosimeters for clinical radiotherapy (RT) with potential applications for transmission monitoring in vivo dosimetry and pre-treatment dose verifications. Thin (≈1 μm) layers of a high sensitivity, wide bandgap semiconductor, the inorganic perovskite CsPbCl₃, have been grown for the first time by magnetron sputtering on plastic substrates equipped with electrode arrays. Prototype devices have been tested in real-time configuration to evaluate the dose delivered by a 6 MV photon beam from a linear accelerator. Linearity of the charge with the dose has been verified over three order of magnitudes, linearity of the current signal with the dose rate has been also successfully tested in the range 0.5-4.3 Gy/min. The combination of high sensitivity per unit volume and wide bandgap provides high signal-to-noise ratios, up to 70, even at moderate applied voltages. The Schottky diode configuration allows the detector to operate without bias voltage (null bias).The blocking-barrier structure allows to confine the active volume within sub-millimetric sizes, a quite attractive feature in view to increase granularity and achieve the high spatial resolutions required in modern RT techniques. All the above-mentioned features indeed pave the way to a novel generation of flexible, transmission, real time dosimeters for clinical radiotherapy.     

Improving Lesbian,Gay, Bisexual,Transgender, Queer and Two-Spirit Content in a Radiation Therapy Undergraduate Curriculum

Lesbian, gay, bisexual, transgender, queer and two-spirit plus (LGBTQ2S+) people have distinct healthcare needs that may be unaddressed in many undergraduate healthcare curricula. The Radiation Therapy Program (RADTH) at the University of Alberta underwent a review of the three-year didactic curriculum using an online survey. The survey sought to ascertain if, where and how topics related to LGBTQ2S + healthcare are taught. Results indicated that out of 10 RADTH program faculty respondents, three teach related topics. The total time dedicated within the three-year curriculum was approximately three and a half hours. Other findings showed that faculty are interested in receiving more education in this area and would favour discussions about how to incorporate these themes into appropriate courses. This preliminary investigation demonstrated that there has been some initial work in this area, but there is more to be done.     

基于中医古籍文献的升降散应用溯源及探析

通过对中医古籍中有关升降散论述的文献梳理,全面探讨其内涵。本方是在大黄、僵蚕为雏形的基础上增加蝉蜕、姜黄而成方,几经易名,终在杨璿《伤寒瘟疫条辨》中为后人所熟知。本方广泛用于治疗瘟疫,以丸剂、散剂为主,方便携带,便于服用;重用大黄旨在祛邪、逐秽;应用时视人之体质强弱和量其毒之轻重而判断用药多寡,并辅以米酒、生蜜等以顾护正气。杨璿将其由治疗“热疫”的专方扩展为治疗“表里三焦大热”的通用方剂,扩大了本方治疗疾病范围。     

El papel de la resonancia magnética multiparamétrica en el diagnóstico de la recidiva local tras la prostatectomía radical y antes de la radioterapia de rescate

PurposeAssess multiparametric-MRI (mp-MRI) diagnostic accuracy in the detection of local recurrence of prostate cancer (PCa) after radical prostatectomy (PR) and before radiation therapy (RT).Materials and methodsA total of 188 patients underwent 1.5-T mp-MRI after RP before RT. Patients were divided into 2 groups: with biochemical recurrence (group A) and without but with high risk of local recurrence (group B). Continuous variables were compared between 2 groups using Student-t test; categoric variables were analyzed using Pearson chi-square. ROC analysis was performed considering PSA before RT, ISUP, pT and pN as grouping variables.ResultsPCa recurrence (reduction of PSA levels after RT) was 89.8% in group A and 80.3% in group B. Comparing patients with and without PCa recurrence, there was a significant difference in PSA values before RT for group A and for PSA values before RT and after RT for group B. In group A, there was a significant correlation between PSA before RT and diameter of recurrence and between PSA before RT and time spent before recurrence. The mp-MRI diagnostic accuracy in detecting PCa local recurrence after RP is of 62.2% in group A and 38% in group B. Diffusion weighted imaging is the most specific MRI-sequence and dynamic contrast enhanced the most sensitive. For PSA = 0.5 ng/ml, the AUC decreases while sensitivity and accuracy increase for each MRI-sequence. For PSA = 0.9 ng/ml, dynamic contrast enhanced-AUC increases significantly.Conclusionmp-MRI should always be performed before RT when a recurrence is suspected. New scenarios can be opened considering the role of diffusion weighted imaging for PSA ≤ 0.5 ng/ml.     

高渗盐水和甘露醇在动脉瘤性蛛网膜下腔出血患者降低颅内压中的应用

目的比较3%高渗盐水和20%甘露醇治疗重症动脉瘤性蛛网膜下腔出血所致颅内压增高的疗效.方法25例动脉瘤性蛛网膜下腔出血患者出现颅内压增高事件时, 随机交替接受等渗透剂量的160 mL 3%高渗盐水与150 mL 20%甘露醇进行降低颅内压治疗, 连续监测患者颅内压、平均动脉压、脑灌注压及中心静脉压.记录有效降低颅内压持续时间、颅内压最大降幅及其时间, 用药前及用药后1 h、3 h血钠水平及血浆渗透压.结果3%高渗盐水和20%甘露醇均可降低颅内压(均 P < 0.01), 两者的降低颅内压作用持续时间及颅内压降幅差异均无统计学意义(均 P >0.05).患者脑灌注压较用药前均上升(均 P < 0.01), 平均动脉压先上升后下降, 但差异无统计学意义( P >0.05).患者中心静脉压稍有波动, 但差异均无统计学意义(均 P >0.05).20%甘露醇治疗后患者血钠下降, 3%高渗盐水治疗后患者血钠值上升, 变化均有统计学意义(均 P < 0.05).20%甘露醇及3%高渗盐水治疗后患者血浆渗透压均先上升后下降, 变化均有统计学意义(均 P < 0.01). 结论3%高渗盐水可作为治疗动脉瘤性蛛网膜下腔出血所致颅内压增高患者的一线治疗药物.     

基于剂量组学预测肺癌患者放射性肺炎发生的研究

目的 探讨剂量组学在预测肺癌根治性放疗患者放射性肺炎发生中的应用潜能。方法 回顾性收集行根治性放疗的314例肺癌患者的临床资料、放疗剂量文件、定位及随访CT图像,根据临床资料及影像学随访资料对放射性肺炎进行分级,提取全肺的剂量组学特征,构建机器学习模型。应用1000次自助抽样法（bootstrap）的最小绝对值收敛和选择算子嵌套逻辑回归（LASSO‐LR）及1000次bootstrap的赤池信息量准则（AIC）向后法筛选与放射性肺炎相关的剂量组学特征,随机按照7∶3划分为训练集及验证集,应用逻辑回归建立预测模型,并应用ROC曲线及校正曲线评价模型的性能。结果 共提取120个剂量组学特征,经LASSO‐LR降维筛选得到12个特征进入“特征池”,再经过AIC向后法筛选,最终筛选出6个剂量组学特征进行模型构建,训练集AUC为0.77（95%CI为0.65~0.87）,独立验证集AUC为0.72（95%CI为0.64~0.81）。结论 利用剂量组学建立的预测模型具有预测放射性肺炎发生的潜力,但仍需继续纳入多中心数据及前瞻性数据进一步挖掘剂量组学的应用潜能。     

An Evidence-Based Review of Total Body Irradiation

The purpose of this literature review is to investigate clinical treatment methods of total body irradiation within the context of a clinical department adopting a paediatric cohort with no existing technique. An extensive review of the literature was conducted using PubMed, Science Direct, Google Scholar, and Clinicians Knowledge Network. Articles were limited to nonhelical tomotherapy, nonparticle therapies, and those using hyperfractionated regimes. Total marrow irradiation was excluded because of national treatment and trial limitations. Of the numerous patient positioning methods present within the literature, the most comfortable and reproducible positioning methods for total body irradiation include both supine and the supine and/or prone combination. These positions increased stability and patient comfort during treatment, while also facilitating computed tomography data acquisition at the simulation stage. Ideally, dose calculations should be performed using a three-dimensional treatment planning system and quality assurance procedures that include in vivo dosimetry measurements. The available literature also suggests inhomogeneity correction factors and intensity modulation are superior to conventional open field techniques and should be implemented within developing protocols. Dynamic machine dose modulation is suggested to reduce department impact, removing the need for tissue compensators and accessory shielding devices, while providing significant improvements to treatment time and dose accuracy. Further long-term survival and intensity modulation studies are warranted, including direct comparisons of both dose modulation and treatment efficiency.     

Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons

BackgroundProstatic radiation therapy (RT) often causes erectile dysfunction (ED) and the mechanisms governing RT-induced ED are unclear with a lack of therapeutic strategies.AimTo determine the effects of ex vivo RT on major pelvic ganglion (MPG) neuron survival, and neurite growth in whole vs dissociated culture.MethodsMPGs were removed and irradiated (0 or 8 Gy) from male Sprague Dawley rats. For dissociated culture, MPG neurons were digested in collagenase/dispase and cultured on coverslips. Immunofluorescent staining for beta-tubulin III (TUBB3; neuron marker), neuronal nitric oxide synthase (nNOS; nitrergic marker), tyrosine hydroxylase (TH; sympathetic marker), and terminal deoxynucleotidyl transferase dUTP nick end labeling assessed neurite length, branching, autonomic neuron density, and apoptosis. For whole organ culture, MPGs were grown in Matrigel. Gene expression of apoptotic markers (caspase 1, 3), TUBB3, nNOS, TH, and Schwann cells (Sox10, Krox20, glial fibrillary acid protein) was measured in whole organ cultured MPGs by quantitative polymerase chain reaction.OutcomesAfter 72 hours, neurite length, branching, autonomic neuron density, and apoptosis were assessed, and gene expression was measured.ResultsRT increased apoptosis in dissociated neurons measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (P < .001) and whole MPG culture via upregulation of caspase 3 gene expression (P < .05). Nitrergic neurons were markedly decreased in irradiated dissociated culture (P < .05), while nNOS gene expression was upregulated in irradiated whole organ culture (P < .05). The proportion of dissociated sympathetic neurons and whole organ TH gene expression remained unchanged after RT. Interestingly, RT dissociated neurites were 22% shorter than controls, while RT whole organ neurites were 15% longer than controls (P < .01). MPG Schwann cells markers (Sox10, Krox20) were elevated after RT in whole organ culture.Clinical TranslationProstatic RT leads to increased neuronal cell death and less erectogenic nitrergic neurons contributing to ED.Strengths & LimitationsThe advantages of dissociated neuron culture include distinct neurites which are easily measured for apoptosis, length/branching, and specific neuron types. In contrast, whole MPG culture is advantageous as it contains all the supporting cells present in vivo.ConclusionThe 2 different culture methods demonstrated opposing neurite growth after RT indicating the importance of supporting cell network to promote pelvic neuron neuritogenesis and survival following RT.Randolph JT, Pak ES, Koontz BF, et al. Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons. J Sex Med 2020;17:1423–1433.     

An Environmental Scan of the National and Provincial Diagnostic Reference Levels in Canada for Common Adult Computed Tomography Scans

Several regulatory bodies have agreed that low-dose radiation used in medical imaging is a weak carcinogen that follows a linear, non-threshold model of cancer risk. While avoiding radiation is the best course of action to mitigate risk, computed tomography (CT) scans are often critical for diagnosis. In addition to the as low as reasonably achievable principle, a more concrete method of dose reduction for common CT imaging exams is the use of a diagnostic reference level (DRL). This paper examines Canada's national DRL values from the recent CT survey and compares it to published provincial DRLs as well as the DRLs in the United Kingdom and the United States of America for the 3 most common CT exams: head, chest, and abdomen/pelvis. Canada compares well on the international scale, but it should consider using more electronic dose monitoring solutions to create a culture of dose optimization.