二维自动切割机制作肿瘤适形放疗挡块在肿瘤放射治疗中的应用

随着肿瘤放疗工作的不断发展,如今肿瘤的放射治疗技术在目前已经发生了很大的变化,精确定位﹑精确计划和精确摆位的原则在临床实践工作中得到了广泛应用。挡铅制造是实现精确计划、达到精确摆位的一个非常重要的环节,对于适形放疗尤为重要。使用挡块的目的不仅是将规则野变成不     

肿瘤放射治疗铅挡块技术

现代放射治疗已进入精确定位、精确计划和精确治疗的三精时代,目标是达到高精度、高剂量、高疗效和低损伤的三高一低放疗模式。相应的出现了多叶准直器（MLC）和适形调强放射治疗技术（IMRT）及图像引导下的放疗技术（IGRT）的发展。基层放疗科大多都是配备了外置电动多叶光栅,往往外置电动多叶光栅的开口较小,不能完全满足临床靶区的需要,又有很多情况下不适合分靶区照射,在这种情况下需要做铅挡块。射野档块可以做到与靶区高度适形、精确放疗的目的。电子线的个体化挡铅及某些特殊照射野的挡铅等都要用到挡块技术。射野挡块技术作为放射治疗中被证实有效的,发展较为成熟的一个组成部分,仍将继续发挥其主要作用。     

鼻咽癌放疗低熔点铅挡块制作误差相关因素分析

目的：探讨鼻咽癌放射治疗面颈联合照射野低熔点铅挡块制作误差的原因.方法：对不合格的低熔点铅挡块进行观察和分析,重新分为四组进行制作,对照分析和评估.结果：鼻咽癌放射治疗面颈联合照射野低熔点铅挡块误差与技师操作、切割机精度、泡沫材料的密度、熔铅炉的温度相关 （P〈0.05）.结论：加强制作铅挡块技师的培训,调试好制作设备的精度,保证泡沫材料的高密度,控制好熔铅炉的温度,能够减少鼻咽癌面颈联合野铅挡块的综合误差.     

介绍一种新型X线放疗适形挡块浇铸模具

适形放疗作为当今一种先进的放疗方法正逐步在业内推广，挡块的制作是实现这一方式的一个重要环节。笔者设计了一种使用简单、结构可靠的挡块浇铸模具，并对其组成和使用方法做了介绍。     

改进头颈部恶性肿瘤外照射放疗技术的临床观察

目的探讨改进头颈部恶性肿瘤外照射放疗技术的疗效及副反应。方法经病理确诊头颈部恶性肿瘤95例，头颈部用头枕面罩固定，低熔点铅挡块技术，等中心照射，一般肿瘤根治剂量72(70～80)Gy，非霍奇金淋巴瘤50～55Gy；预防剂量56(50—60)Gy，非霍奇金淋巴瘤45～50Gy。结果放疗后1～2个月CT复查可评价的肿瘤完全消退率58.57％，明显消退率32．86％，正常组织急性放射相关性粘膜炎发生率0级56.84％，1级42.10％，2级1.05％，随访1-2年脊髓脑干晚期放射反应为0。结论改进的外照射放疗技术对头颈部恶性肿瘤照射更准确，局部控制率高，放射损伤率低。     

42例头颈部肿瘤患者放疗临床护理应用

探讨整体护理再头颈部肿瘤患者放疗中的护理效果。选择42例头颈部肿瘤放疗患者作为研究对象,分为研究组与对照组,各21例。对照组实施常规医护引导与对症护理,研究组整体护理。护理后,研究组患者整体生活质量水平及满意度均明显高于对照组（P<0.05）,具有统计学意义。整体护理对头颈部肿瘤放疗患者能进一步提升患者生活质量水平,满意度较高,值得广泛推广应用。     

鼻咽癌面颈联合野适形铅挡块制作技术改进及应用

目的提高适形低熔点铅挡块的制作精度和速度以改进鼻咽癌放疗技术。方法用电脑图像处理软件photoshop6.0编辑胶片扫描仪扫描的已勾画靶区的模拟定位X -光片图像 ,打印出不规则野在等中心水平面的轮廓图 (SAD图 )和托盘面缩小的轮廓图 (STD图 )及其镜像图 ;热丝切割机根据SAD图切割出与STD图上射野轮廓大小相同的聚焦式泡沫塑料阳模 ;然后用该阳模、STD图、磁性钢板、托盘等浇铸内孔适形低熔点铅挡块。结果制作20cm×20cm内任意形状的适形铅挡块 ,浇铸冷却时间少于5分钟 ,挡块外形光滑 ,用预浇螺钉固定十分牢靠且误差可小于1mm,放疗时摆位方便 ,准确性好。结论电脑图像处理技术结合磁性钢模制作适形低熔点铅挡块的方法行之有效 ,提高了放疗摆位的精度和速度     

二维自动切割机制作适形放疗挡块的应用

目的:探讨二维自动切割机在现代放疗中的价值。材料与方法:采用德国的Hek–Medizintechnik 2D自动切割机(切割速度=0.4、热力电流=1.48A、快速移动速度=4、切割模式的宽度=0.01cm﹑安全边界=2cm、安全距离=3cm、切割模式为自动、挡块Block发散)、聚乙稀泡沫体积为30×30×8cm、绘图仪,对100块挡块进行回顾性分析。结果:2D自动切割机的应用能够把挡块与射野形状之间的径向误差控制在0.1cm之内。结论:二维自动切割机设计制作的挡块经等中心验证,可以做成高精度的挡块。     

射野挡块的制作及经验

在放射治疗中,射野时一般应加上挡块,其目的在于使规则照射野变成不规则照射野以适应靶区和计划区形状的需要以及保护射野内的重要器官和正常组织免受不必要的照射。因而,制作射野挡块是日常治疗活动．必不可少的一环。因为射野挡块制笸会受到多方因素的影响,为了更好地制作合格的射野挡块。本文将重点阐述挡块制作方法及经验体会。     

电动颅骨钻的改进

在电动颅骨钻的电机驱动电路中加一过载保护电路，使其运行可靠。     

食管癌三维适形放射治疗与常规放射治疗定位的对比

目的对比食管癌三维适形放射治疗与常规放射治疗两种方式所使用定位方法的优、缺点。方法对12例食管癌患者均进行CT模拟定位与常规模拟定位,然后对两种不同的定位方法在靶区面积、剂量分布和等中心位置等方面情况进行对照分析。结果两种定位方法靶区面积差异有统计学意义。计划靶体积周边被90％等剂量曲线所包括的计划中三维适形放射治疗有12例,常规放射治疗有4例。结论三维适形放射治疗使用的CT模拟定位所显示的肿瘤浸润的范围比常规放射治疗的模拟机定位显示得更加充分,但在确定肿瘤长度时不如后者,所以常规模拟机的食管吞钡片应作为确定肿瘤长度的重要参考。     

常规放疗模拟机的日常质控目标和校准方法

目的：探讨常规放疗模拟定位机的质量保证（quality assurance,QA）和质量控制（quality control,QC）的主要内容及检测方法,以保证临床放疗定位的稳定性,提高治疗实施的准确性和精度。方法：从常规模拟定位机的机械等中心调整、辐射野光野的指示校准、光距尺的检验和校准、激光定位灯的调整以及辐射防护与设备安全连锁等方面分析确认QA和QC的主要内容和检测方法。结果：得出了日常放射治疗工作中常规模拟定位机必须予以实施的QA和QC的主要内容以及检测方法。结论：依据常规模拟机日常的QA和QC的主要内容及检测方法,制定了适合本单位实际情况的QA和QC检测规范和标准,从根本上保证了放射治疗定位的精度,同时对各级放射治疗单位常规模拟机质量保证体系的建立具有现实指导作用。     

Comparison of skin dose between conventional radiotherapy and IMRT

The purpose of this study was to measure skin dose using radiochromic film for two step-and-shoot IMRT fields and compare the results to the skin dose for a conventional open field. All exposures were made using a 6 MV photon beam produced by a Varian 21EX linear accelerator (Varian Medical Systems, CA, USA) equipped with a Millennium 120 leaf MLC. Three different field configurations were used, these were an open field, a step-and-shoot IMRT field and a clinical IMRT field. The mean ratio of the skin dose to dose at d(max) for an open 10 x 10 cm2 field at 100 cm SSD was 0.178 +/- 0.003. The step-and-shoot IMRT field consisted of 1 cm wide strips of decreasing intensity that were delivered using a step-and-shoot technique across a 10 x 10 cm2 field. The ratio of skin dose to dose at d(max) ranged from 0.180 to 0.257, with the low intensity steps having a higher relative skin dose compared to the high intensity steps. A model was derived that attributed these variations to the electron contamination from both the adjacent and more distant high intensity steps. The clinical field consisted of a 25 segment 9.8 x 10.0 cm2 beam arrangement. The ratio of skin dose to dose at d(max) for the clinical IMRT field ranged from 0.093 to 0.284. The results indicated that an IMRT field produced only minor changes in the relative skin dose, with variations potentially attributable to fluctuations in the electron contamination produced by neighbouring regions of different intensity. The use of an individual IMRT field does not significantly increase the skin dose above that of a conventional photon field.     

食管癌三维适形放射治疗与常规放射治疗定位的对比

目的对比食管癌三维适形放射治疗与常规放射治疗两种方式所使用定位方法的优、缺点。方法对12例食管癌患者均进行CT模拟定位与常规模拟定位，然后对两种不同的定位方法在靶区面积、剂量分布和等中心位置等方面情况进行对照分析。结果两种定位方法靶区面积差异有统计学意义。计划靶体积周边被90％等剂量曲线所包括的计划中三维适形放射治疗有12例，常规放射治疗有4例。结论三维适形放射治疗使用的CT模拟定位所显示的肿瘤浸润的范围比常规放射治疗的模拟机定位显示得更加充分，但在确定肿瘤长度时不如后者，所以常规模拟机的食管吞钡片应作为确定肿瘤长度的重要参考。     

直肠癌术后常规放射治疗摆位误差分析

目的:通过对直肠癌术后常规放射治疗重复摆位数据的测量,分析误差产生原因,并采取针对性措施减少误差.方法:13例直肠癌术后放射治疗患者,仰卧于床上,采用真空袋固定,由模拟定位机工作站采集定位图像,行等中心放射治疗.每周一、三、五采集验证片,与原定位片比较,测量摆位误差.结果:156幅验证图像与其对应的定位图像比较,X、y、Z轴误差分别为(0.32±0.17)、(0.58±0.27)、(0.53±0.31)cm,正、侧面移位旋转分别为(2.3±1.9)和(1.8±1.6)°.结论:直肠癌术后常规放射治疗中重复摆位存在一定误差,通过采取相应措施可以减小.     

Transitioning from conventional radiotherapy to intensity-modulated radiotherapy for localized prostate cancer: changing focus from rectal bleeding to detailed quality of life analysis

With the advent of modern radiation techniques, we have been able to deliver a higher prescribed radiotherapy dose for localized prostate cancer without severe adverse reactions. We reviewed and analyzed the change of toxicity profiles of external beam radiation therapy (EBRT) from the literature. Late rectal bleeding is the main adverse effect, and an incidence of >20% of Grade ≥2 adverse events was reported for 2D conventional radiotherapy of up to 70 Gy. 3D conformal radiation therapy (3D-CRT) was found to reduce the incidence to ∼10%. Furthermore, intensity-modulated radiation therapy (IMRT) reduced it further to a few percentage points. However, simultaneously, urological toxicities were enhanced by dose escalation using highly precise external radiotherapy. We should pay more attention to detailed quality of life (QOL) analysis, not only with respect to rectal bleeding but also other specific symptoms (such as urinary incontinence and impotence), for two reasons: (i) because of the increasing number of patients aged >80 years, and (ii) because of improved survival with elevated doses of radiotherapy and/or hormonal therapy; age is an important prognostic factor not only for prostate-specific antigen (PSA) control but also for adverse reactions. Those factors shift the main focus of treatment purpose from survival and avoidance of PSA failure to maintaining good QOL, particularly in older patients. In conclusion, the focus of toxicity analysis after radiotherapy for prostate cancer patients is changing from rectal bleeding to total elaborate quality of life assessment.     

Second malignancies following conventional or combined 252Cf neutron brachytherapy with external beam radiotherapy for breast cancer

We retrospectively evaluated the risk of second malignancies among 832 patients with inner or central breast cancer treated with conventional external beam schedule (CRT group), or neutron brachytherapy using Californium-252 (²⁵²Cf) sources and hypofractionated external beam radiotherapy (HRTC group), between 1987 and 1996 at the Institute of Oncology, Vilnius University. Patients were observed until the occurrences of death or development of a second malignancy, or until 31 December 2009, whichever was earlier. Median follow-up time was 10.4 years (range, 1.2–24.1 years). Risk of second primary cancers was quantified using standardized incidence ratios (SIRs). Cox proportional hazards regression models were used to estimate hazard ratios (HRs). There was a significant increase in the risk of second primary cancers compared with the general population (SIR 1.3, 95% CI 1.1–1.5). The observed number of second primary cancers was also higher than expected for breast (SIR 1.8, 95% CI 1.3–2.4) and lung cancer (SIR 3.8, 95% CI 2.0–6.7). For second breast cancer, no raised relative risk was observed during the period ≥10 or more years after radiotherapy. Compared with the CRT group, HRTC patients had a not statistically significant higher risk of breast cancer. Increased relative risks were observed specifically for age at initial diagnosis of <50 years (HR 2.9, 95% CI 1.6–5.2) and for obesity (HR 2.8, 95% CI 1.1–7.2).