SBRT for lung oligometastases: Who is the perfect candidate?

AimTo analyze the literature data about lung oligometastatic patients who underwent SBRT with regard to doses, fractionation, outcomes, response assessment and prognostic factors, trying to define “the right patient” for the local treatment.Background“Oligometastatic disease” is defined as a state in which metastases are limited in number and site and characterized by unusual cancer biology and behavior. In this setting local therapy could have a potential curative role. Recently, technological advances in Radiation Oncology permitted the introduction of Stereotactic Body Radiation Therapy (SBRT), a novel treatment modality that delivers ablative dose of radiation to the extra-cranial sites with high precision using single or a small number of fractions.Materials and methodsWe performed a literature search using Medical Subject Heading terms “stereotactic body radiation therapy” and “lung metastases”, considering a period of 10 years.ResultsMany non-randomized studies have shown that SBRT for lung oligometastases is safe and effective, with local control rates of about 80%. To date SBRT represents an alternative and competitive option in patients with lung oligometastatic disease who refuse surgical treatment or unsuitable for surgery. Based on published studies, SBRT might have major benefit for a patient with breast histology, disease-free interval ≥12 months, control of the primary tumor, small lesions, limited number of lesions and higher radiation dose delivered.ConclusionsWell-designed collaborative trials are necessary to draw final conclusions. To date, the discussion within a multidisciplinary team becomes crucial to perform a careful patients’ selection in the setting of oligometastatic disease.     

On the use of AAA and AcurosXB algorithms for three different stereotactic ablative body radiotherapy (SABR) techniques: Volumetric modulated arc therapy (VMAT), intensity modulated radiation therapy (IMRT) and 3D conformal radiotherapy (3D-CRT)

AimThe purpose of this study was to investigate the dosimetric characteristics of three stereotactic ablative body radiotherapy (SABR) techniques using the anisotropic analytical algorithm (AAA) and Acuros XB algorithm. The SABR techniques include coplanar volumetric modulated arc therapy (C-VMAT), non-coplanar intensity modulated radiation therapy (NC-IMRT) and non-coplanar three-dimensional conformal radiotherapy (NC-3D CRT).BackgroundSABR is a special type of radiotherapy where a high dose of radiation is delivered over a short time. The treatment outcome and accuracy of the dose delivered to cancer patients highly depend on the dose calculation algorithm and treatment technique.Materials and methodsTwelve lung cancer patients underwent 4D CT scanning, and three different treatment plans were generated: C-VMAT, NC-IMRT, NC-3D CRT. Dose calculation was performed using the AAA and Acuros XB algorithm. The dosimetric indices, such as conformity index (CI), homogeneity index, dose fall-off index, doses received by organs at risk and planning target volume, were used to compare the plans. The accuracy of AAA and Acuros XB (AXB) algorithms for the lung was validated against measured dose on a CIRS thorax phantom.ResultsThe CIs for C-VMAT, NC-IMRT and NC-3D CRT were 1.21, 1.28 and 1.38 for the AAA, respectively, and 1.17, 1.26 and 1.36 for the Acuros XB algorithm, respectively. The overall dose computed by AcurosXB algorithm was close to the measured dose when compared to the AAA algorithm. The overall dose computed by the AcurosXB algorithm was close to the measured dose when compared to the AAA algorithm.ConclusionThis study showed that the treatment planning results obtained using the Acuros XB algorithm was better than those using the AAA algorithm in SABR lung radiotherapy.     

Australia's oldest human remains: age of the Lake Mungo 3 skeleton

We have carried out a comprehensive ESR and U-series dating study on the Lake Mungo 3 (LM3) human skeleton. The isotopic Th/U and Pa/U ratios indicate that some minor uranium mobilization may have occurred in the past. Taking such effects into account, the best age estimate for the human skeleton is obtained through the combination of U-series and ESR analyses yielding 62,000+/-6000 years. This age is in close agreement with OSL age estimates on the sediment into which the skeleton was buried of 61,000+/-2000 years. Furthermore, we obtained a U-series age of 81,000+/-21,000 years for the calcitic matrix that was precipitated on the bones after burial. All age results are considerably older than the previously assumed age of LM3 and demonstrate the necessity for directly dating hominid remains. We conclude that the Lake Mungo 3 burial documents the earliest known human presence on the Australian continent. The age implies that people who were skeletally within the range of the present Australian indigenous population colonized the continent during or before oxygen isotope stage 4 (57,000-71,000 years).     

SBRT for prostate cancer: Challenges and features from a physicist prospective

Emerging data are showing the safety and the efficacy of Stereotactic Body Radiation Therapy (SBRT) in prostate cancer management. In this context, the medical physicists are regularly involved to review the appropriateness of the adopted technology and to proactively study new solutions. From the physics point of view there are two major challenges in prostate SBRT: (1) mitigation of geometrical uncertainty and (2) generation of highly conformal dose distributions that maximally spare the OARs. Geometrical uncertainties have to be limited as much as possible in order to avoid the use of large PTV margins. Furthermore, advanced planning and delivery techniques are needed to generate maximally conformal dose distributions. In this non-systematic review the technology and the physics aspects of SBRT for prostate cancer were analyzed. In details, the aims were: (i) to describe the rationale of reducing the number of fractions (i.e. increasing the dose per fraction), (ii) to analyze the features to be accounted for performing an extreme hypo-fractionation scheme (>6–7 Gy), and (iii) to describe technological solutions for treating in a safe way. The analysis of outcomes, toxicities, and other clinical aspects are not object of the present evaluation.     

早期周围型肺癌的X线动态观察和分析

目的探讨X线动态观察对周围型肺癌进行早期诊断的价值。方法对有X线随访资料的早期周围型肺癌14例资料进行回顾性分析。结果病灶直径≤2cm,无局部、远处、肺门及纵隔淋巴结等转移者归为早期征象;病灶直径〉2cm以上,有或无肺门,纵隔淋巴结、骨及胸膜转移者归为进展期征象。鉴别诊断中,除考虑形态学改变外,还要注意观察肿瘤的生长速度。结论X线平片发现类似病灶,应进行动态观察,查看有无恶性征象,再结合临床资料进行鉴别诊断。     

基于医疗数据信息集成系统的3D打印技术在肺癌手术中的应用

目的:探讨基于医疗数据信息集成系统的3D打印技术在治疗肺癌中的应用。方法:2014年10月~2015年10月收治的符合肺癌临床路径,进入医疗数据信息集成系统,并接受320排螺旋CT扫描三维重建,3D打印出实体1:1大小的患侧肺血管及肺病灶模型,术前制定手术方案且模拟手术过程的42例非小细胞肺癌(NSCLC)患者,经电视胸腔镜应用内镜缝合切割器切除病灶,术中快速冰冻切片明确诊断,行肺段切除术,肺叶切除术。观察术中肺血管与3D打印符合程度。记录手术时间、术中出血量、切除淋巴结数量、有无术中死亡、病理结果、并发症、引流时间和引流量及术后生存情况。结果:术中证实95%以上的肺血管可被3D打印出来。手术时间(51.4±18.1)min,术中出血量(40.2±20.3)mL。切除淋巴结(7.1±2.8)枚。无术中死亡。术后病理回报示肺鳞癌13例,肺腺癌29例。病理分期:T1aN0M0 12例,T1aN1M0 10例,T1bN0M0 3例,T1bN1M0 3例,T2aN0M0 2例,T2aN1M0 12例。术后患者无严重并发症,其中肺感染6例、肺膨胀不全6例、房颤5例,所有患者经积极后痊愈;术后引流时间(3.0±1.2)d,引流量(200.7±66.1)mL/d。42例随访2~12个月,中位随访时间8.0月,40例无瘤生存,术后6个月发生转移脑转移2例,分别于术后7和10个月死亡。结论:基于医疗数据信息集成系统的3D打印技术可以应用于肺癌手术。     

3D打印肺段模型在胸外科解剖教学中的应用

目的:探讨3D打印肺段模型在胸外科解剖教学中的应用效果。方法:60名医学新生随机分为3D打印组和三维重建图像组,每组30人。经相关知识介绍后,参加问卷调查并记录得分,包括理论知识、肺段鉴别、病灶鉴别,共14分。结果:3D打印肺段模型能清晰准确地显示出肺脏结构。3D打印组问卷调查得分显著高于三维重建图像组,差异具有统计学意义(P=0.031)。结论:3D打印肺段模型在医学生肺段解剖教学中的效果优于三维重建图像。