基于CT血管成像的血流储备分数对肺癌的诊断价值

目的:探讨基于CT血管成像的血流储备分数对肺癌淋巴结转移的诊断价值。方法:2018年1月到11月选择在本院进行诊治的肺癌患者60例,所有患者都给予常规CT检查与CT血管成像,记录成像特征与相关血流储备分数-血流量(blood flow,BF)、血容量(blood volume,BV)、平均通过时间(mean transit time,MTT),判断诊断价值。结果:在60例患者中,病理确诊为淋巴结转移20例,非淋巴结转移40例。转移组的毛刺征、分叶征、棘突征、空泡征等CT征象发生率显著高于非转移组(P0.05)。转移组的肺动脉BF、BV值显著低于非转移组(P0.05),MTT值显著高于非转移组(P0.05)。在60例患者中,Spearman相关分析显示淋巴结转移与MTT成显著正相关性(P0.05),与BF、BV值成显著负相关性(P0.05)。结论:CT血管成像在肺癌中的应用能反映患者的血流储备分数状况,有利于判断患者的淋巴结转移情况,有很好的应用价值。     

CT联合MRI在早期肝癌诊断临床价值分析

摘要 目的：探究CT联合MRI在早期肝癌诊断中的应用价值。方法：选择2016年6月至2019年6月于我院接受诊断治疗的78例已知或疑似肝癌患者,分别对其实施CT及MRI检测,以病灶部位病理学检查结果为金标准（50例确诊为早期肝癌,28例为良性病变）,分别评估CT、MRI、CT联合MRI对早期肝癌的诊断价值,将确诊为肝癌的50例患者按照病灶大小区分为直径≤3 cm组（21例）和>3 cm组（29例）,对比CT与MRI对不同直径肝癌诊断率。结果：（1）检测发现,CT对早期肝癌诊断一致性为73.08 %,灵敏度为72.00 %,特异度为75.00 %;（2）MRI对早期肝癌诊断一致性为82.05 %,灵敏度为82.00 %,特异度为82.14 %;（3）CT联合MRI检测对早期肝癌诊断一致性为93.59 %,灵敏度为92.00 %,特异度为96.43 %;（4）对比发现,对直径≤3 cm的早期肝癌患者,MRI诊断率明显高于CT（95.24 % vs 76.19 %,P<0.05）。结论：CT及MRI对早期肝癌均具有较好的诊断价值,但联合检测明显优于任一单独检测,同时对病灶直径≤3 cm的早期肝癌患者,MRI诊断准确率更高。     

CT与MRI扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用

摘要 目的：探讨电子计算机断层扫描(Computed Tomography,CT)与磁共振成像(Magnetic resonance imaging,MRI)扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用。方法：2016年9月到2019年10月选择在本院诊治的下拟诊为四肢骨关节隐匿性骨折118例,所有患者都给予CT与MRI扫描三维重建诊断,记录影像学特征与判断诊断价值。结果：在118例患者中,最终确诊为四肢骨关节隐匿性骨折98例,无骨折20例,其中腕关节骨折34例,踝关节骨折22例,膝关节骨折15例,肘关节骨折15例,肩关节骨折8例,髋关节骨折4例。在98例确诊的四肢骨关节隐匿性骨折中,MRI三维重建显示双边征、骨质破坏、充气征、软组织影等比例显著都高于CT (P<0.05)。CT与MRI三维重建诊断四肢骨关节隐匿性骨折的敏感性为89.8 %和99.0 %,特异性为95.0 %和100.0 %,误诊率分别为9.3 %和0.8 %,MRI三维重建诊断的敏感性高于CT ,漏诊率低于CT。结论：CT与MRI扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用都有很好的价值,特别是MRI三维重建能清晰显示骨折特征,具有更高的诊断敏感性,能减少漏诊率,可作为四肢骨关节隐匿性骨折的首选检查方法。     

低剂量与常规剂量扫描在CT引导下经皮穿刺肺活检术中的临床应用价值对比研究

摘要 目的：比较低剂量与常规剂量扫描在CT引导下经皮穿刺肺活检术中的临床应用价值。方法：选择2018年1月至2019年12月我院行CT引导下经皮穿刺肺活检术的患者96例,采用随机数字表法分为低剂量组和常规剂量组,每组48例,两组分别在低剂量扫描、常规剂扫描下行CT引导下经皮穿刺肺活检术,比较两组扫描范围、X射线剂量、图像质量、穿刺成功率及并发症发生情况。结果：低剂量组CT吸收剂量加权指数（CTDIw）、平均剂量长度乘积（DLP）显著低于常规剂量组（P<0.05）,两组扫描范围比较无统计学差异（P>0.05）。低剂量组图像质量1级1例、2级1例、3级46例;常规剂量组1级0例、2级1例、3级47例,两组图像质量比较无统计学差异（P>0.05）。低剂量组穿刺成功率87.50%,常规剂量组穿刺成功率89.58%,两组穿刺成功率比较无统计学差异（P>0.05）。低剂量组并发症发生率为12.50%,常规剂量组并发症发生率为10.42%,两组并发症发生率比较差异无统计学意义（P>0.05）。结论：与常规剂量扫描相比,在CT引导下经皮穿刺肺活检术中应用低剂量扫描可以有效降低辐射剂量,但不影响图像质量和穿刺成功率,患者并发症发生率也未增加,具有较好的临床价值。     

Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017

Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements. This study reveals that the terrestrial carbon uptake over the Republic of Korea has been enhanced from 1999 to 2017 by analyzing long‐term atmospheric CO₂ concentration measurements at the Anmyeondo Station (36.53°N, 126.32°E) located in the western coast. The influence of terrestrial carbon flux on atmospheric CO₂ concentrations (ΔCO₂) is estimated from the difference of CO₂ concentrations that were influenced by the land sector (through easterly winds) and the Yellow Sea sector (through westerly winds). We find a significant trend in ΔCO₂ of ?4.75 ppm per decade (p < .05) during the vegetation growing season (May through October), suggesting that the regional terrestrial carbon uptake has increased relative to the surrounding ocean areas. Combined analysis with satellite measured normalized difference vegetation index and gross primary production shows that the enhanced carbon uptake is associated with significant nationwide increases in vegetation and its production. Process‐based terrestrial model and inverse model simulations estimate that regional terrestrial carbon uptake increases by up to 18.9 and 8.0 Tg C for the study period, accounting for 13.4% and 5.7% of the average annual domestic carbon emissions, respectively. Atmospheric chemical transport model simulations indicate that the enhanced terrestrial carbon sink is the primary reason for the observed ΔCO₂ trend rather than anthropogenic emissions and atmospheric circulation changes. Our results highlight the fact that atmospheric CO₂ measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle even where anthropogenic emissions are not negligible.     

Monte Carlo study on the secondary cancer risk estimations for patients undergoing prostate radiotherapy: A humanoid phantom study

AimThe aim of this study was to estimate the secondary malignancy risk from the radiation in FFB prostate linac-based radiotherapy for different organs of the patient.BackgroundRadiation therapy is one of the main procedures of cancer treatment. However, the application the radiation may impose dose to organs of the patient which can be the cause of some malignancies.Materials and methodsMonte Carlo (MC) simulation was used to calculate radiation doses to patient organs in 18 MV linear accelerator (linac) based radiotherapy. A humanoid MC phantom was used to calculate the equivalent dose s for different organs and probability of secondary cancer, fatal and nonfatal risk, and other risks and parameters related to megavoltage radiation therapy. In out-of-field radiation calculation, it could be seen that neutrons imparted a higher dose to distant organs, and the dose to surrounding organs was mainly due to absorbed scattered photons and electron contamination.ResultsOur results showed that the bladder and skin with 54.89 × 10⁻³ mSv/Gy and 46.09 × 10⁻³ mSv/Gy, respectively, absorbed the highest equivalent dose s from photoneutrons, while a lower dose was absorbed by the lung at 3.42 × 10⁻³ mSv/Gy. The large intestine and bladder absorbed 55.00 × 10⁻³ mSv/Gy and 49.08 × 10⁻³, respectively, which were the highest equivalent dose s due to photons. The brain absorbed the lowest out-of-field dose, at 1.87 × 10⁻³ mSv/Gy.ConclusionsWe concluded that secondary neutron portion was higher than other radiation. Then, we recommended more attention to neutrons in the radiation protection in linac based high energy radiotherapy.     

Simulation of dose distribution and secondary particle production in proton therapy of brain tumor

AimThe aim of this study is simulation of the proton depth-dose distribution and dose evaluation of secondary particles in proton therapy of brain tumor using the GEANT4 and FLUKA Monte Carlo codes.BackgroundProton therapy is a treatment method for variety of tumors such as brain tumor. The most important feature of high energy proton beams is the energy deposition as a Bragg curve and the possibility of creating the spread out Bragg peak (SOBP) for full coverage of the tumor.Materials and methodsA spherical tumor with the radius of 1 cm in the brain is considered. A SNYDER head phantom has been irradiated with 30−130 MeV proton beam energy. A PMMA modulator wheel is used for covering the tumor. The simulations are performed using the GEANT4 and FLUKA codes.ResultsUsing a modulator wheel, the Spread Out Bragg Peak longitudinally and laterally covers the tumor. Flux and absorbed dose of secondary particles produced by nuclear interactions of protons with elements in the head are considerably small compared to protons.ConclusionsUsing 76.85 MeV proton beam and a modulator wheel, the tumor can be treated accurately in the 3-D, so that the distribution of proton dose in the surrounding tissues is very low. The results show that more than 99% of the total dose of secondary particles and protons is absorbed in the tumor.     

High-dose neoadjuvant chemoradiotherapy versus chemotherapy alone followed by surgery in potentially-resectable stage IIIA-N2 NSCLC. A multi-institutional retrospective study by the Oncologic Group for the Study of Lung Cancer (Spanish Radiation Oncology Society)

BackgroundThe optimal induction treatment in potentially-resectable stage IIIA-N2 NSCLC remains undefined.AimTo compare neoadjuvant high-dose chemoradiotherapy (CRT) to neoadjuvant chemotherapy (CHT) in patients with resectable, stage IIIA-N2 non-small-cell lung cancer (NSCLC).MethodsRetrospective, multicentre study of 99 patients diagnosed with stage cT1-T3N2M0 NSCLC who underwent neoadjuvant treatment (high-dose CRT or CHT) followed by surgery between January 2005 and December 2014.Results47 patients (47.5%) underwent CRT and 52 (52.5%) CHT, with a median follow-up of 41 months. Surgery consisted of lobectomy (87.2% and 82.7%, in the CRT and CHT groups, respectively) or pneumonectomy (12.8% vs. 17.3%). Nodal downstaging (to N1/N0) and Pathologic complete response (pCR; pT0pN0) rates were significantly higher in the CRT group (89.4% vs. 57.7% and 46.8% vs. 7.7%, respectively; p < 0.001)). Locoregional recurrence was significantly lower in the CRT group (8.5% vs. 13.5%; p = 0.047) but distant recurrence rates were similar in the two groups. Median PFS was 45 months (CHT) vs. “not reached” (CRT). Median OS was similar: 61 vs. 56 months (p = 0.803). No differences in grade ≥3 toxicity were observed. On the Cox regression analysis, advanced pT stage was associated with worse OS and PFS (p < 0.001) and persistent N2 disease (p = 0.002) was associated with worse PFS.ConclusionsCompared to neoadjuvant chemotherapy alone, a higher proportion of patients treated with preoperative CRT achieved nodal downstaging and pCR with better locoregional control. However, there were no differences in survival. More studies are needed to know the optimal treatment of these patients.     

Higher patient doses through X-ray imaging procedures

Medical imaging using X-rays has been one of the most popular imaging modalities ever since the discovery of X-rays 125 years ago. With unquestionable benefits, concerns about radiation risks have frequently been raised. Computed tomography (CT) and fluoroscopic guided interventional procedures have the potential to impart higher radiation exposure to patients than radiographic examinations. Despite technological advances, there have been instances of increased doses per procedure mainly because of better diagnostic information in images. However, cumulative dose from multiple procedures is creating new concerns as effective doses >100 mSv are not uncommon. There is a need for action at all levels. Manufacturers must produce equipment that can provide a quality diagnostic image at substantially lesser dose and better implementation of optimization strategies by users. There is an urgent need for the industry to develop CT scanners with sub-mSv radiation dose, a goal that has been lingering. It appears that a new monochromatic X-ray source will lead to replacement of X-ray tubes all over the world in coming years and will lead to a drastic reduction in radiation doses. This innovation will impact all X-ray imaging and will help dose reduction. For interventional procedures, the likely employment of robotic systems in practice may drastically reduce radiation exposures to operators- but patient exposure will still remain an issue. Training needs always need to be emphasized and practiced.