直线加速器8mv－x和60Co治疗鼻咽癌疗效比较

 1987年至1989年采用前瞻性随机研究治疗鼻咽癌217例。分为二组,直线加速器（8mv－x）组107例,⁶⁰Co组110例,两组年龄、性别、临床分期、治疗方法、时间剂量等因素基本相同。全组5年随访率为90%,3、5年生存率分别为60.8%和43.8%,8mv－x组分别为67.3%和49.5%,⁶⁰Co组为54.5%和38.2%,8mv－x组较⁶⁰Co组稍好,但无统计学差异（P>0.05）.疗终颈部淋巴结残存率和原发灶复发率8mv－x组为25.6%和11.2%。⁶⁰Co组为34.9%和12.7%（P>0.05）。     

60Co治疗机的临床应用研究现状

 60Co治疗机在放射治疗中有着悠久和辉煌的历史,是重要的放疗设备。如今,放疗已进入精确定位、精确计划、精确治疗的"三精"时代,适形放疗与60Co治疗机相结合可谓给60Co治疗机注入了新的活力,可以实现精确放疗,有利于提高治疗增益比。为了更好地达到"三精"要求,提出了增加源轴距、提高源的活度、校正源传输的端效应及致力提高国内放疗设备的质量和水平等建议。     

直线加速器飞行管接头故障分析

ＳＬｉ18型直线加速器是一台中高能射线的治疗机 ,它分别有二档光子线 (低、高能Ｘ线 )和七档电子线 (4、6、8、10、12、15和 18ＭｅＶ)的能量选择 ,是较好的数字化放射治疗设备。现将其飞行管接头故障原因及处理方法报道如下。1　材料与方法1.1　故障表现 :当设备开始工作后 ,经过 15ｍｉｎ加温 ,控制台监视终端屏幕显示二项指示 :“ＩＮＨＩＢＩＴ 1:ＶＡＣＧＵＮ 42 7;ＩＮＨＩＢＩＴ 2 :ＶＡＣＴＡＲＧ 42 8”。此时 ,机器不能正常运行 ,故障出现。1.2　故障检查与维修 :首先 ,切换到设备维修模式 ,从设备监视终端查看到参数值 ,翻到第 …     

60Co治疗机临床应用的管理

近年来 ,由于肿瘤患者数量的不断增加 ,使得放射治疗 (放疗 )在治疗恶性肿瘤的三大手段中的地位显得更加重要。尽管近年来加速器大量投入 ,但仍有约 6 0 %的放疗病人适宜60 Ｃｏ治疗机的放疗 ,且60 Ｃｏ治疗机具有价格便宜、剂量稳定、利用率高、维修与治疗费用低等优点 ,得到基层单位广泛普及应用 ,基于这种原因 ,临床拟定放疗计划医师及定位摆位技术人员的素质及技术水平和机器的精确度都成为接受60 Ｃｏ放疗病人治疗效果的保障 ,下面根据我们近 30年的放疗经验介绍一下60 Ｃｏ治疗机的管理。放疗医师为保障患者的治愈率应要求计划合理 ,…     

60Co治疗机及其临床应用

195 1年加拿大Johns成功研制了60 Co远距离治疗机 ,195 2年开始投入临床应用 ,这标志着放疗“千伏”时代的结束和“兆伏”时代的开始 ,皮肤毒性明显减轻 ,放疗适应证进一步扩大 ,疗效也明显提高 ,如鼻咽癌患者的 5年生存率从 2 0 %～ 2 5 %提高到了 40 %～ 5 0 % [1] 。我们就6     

利用直线加速器进行立体定向放射治疗

利用医院已有的直线加速器，增添一些必要的设备组成立体定向放射治疗系统。这对于有较长放射治疗历史经验的医院来说是可行的，也是很有意义的工作。国内已有先例。近年来立体定向放射治疗技术在国外发展很快，国内起步于90年代，发展势头不小。立体定向放射治疗技术又可分为两类：一次性给予大剂量照射杀死靶区病灶以代替外科手术和分次给予比常规放疗更大剂量（每次）的立体定向放疗技术。前者为神经外科医生采用，后者多为放疗科医生采用。分次立体定向放疗较常规放疗有明显的优点，即靶区病灶接受剂量大，增大了放射生物杀伤力；剂量分…     

直线加速器8MV—X线和远距离^60Co治疗鼻咽癌近期疗效和疗中反应的比较

直线加速器８ＭＶ－Ｘ线和远距离~（６０）Ｃｏ治疗鼻咽癌近期疗效和疗中反应的比较王安宇副教授广西医科大学肿瘤医院（５３００２１）我国自７０年代末引进医用直线加速器以来，许多患者乃至医务人员常迷信它有特效［１］，导致放射治疗工作中一些脱离实际情况盲目追求?..     

国产^60Co治疗机罕见的卡源故障检修方法

国产６０Ｃｏ治疗机罕见的卡源故障检修方法张春光李凤岩关键词６０Ｃｏ卡源气缸中图号Ｒ７３０．５５附图源输送系统结果结构图Ａ、螺丝Ｂ、螺丝Ｃ、连接头Ｄ、小孔Ｅ、活塞连杆Ｆ、载源杆在以压缩空气驱动６０Ｃｏ源的气动式６０Ｃｏ放射治疗机，治疗的开始，通过电路控...     

基于电子直线加速器的肿瘤立体定向放射治疗物理实践指南

立体定向放射治疗具有单次照射剂量大、分割次数少、边缘剂量下降快的特点。治疗过程中应使用最精准的设备,执行最严格、最规范的操作。本指南旨在建立起国内可通用的、立体定向放疗(SRT)临床实践工作所需的医学物理支持的最低要求,帮助国内放疗单位能够正确安全地开展SRT技术。各单位在使用本指南时,需结合本单位SRT设备特点和患者治疗情况,制定明确细致的标准操作程序。     

Cobalt-60 therapy unit for large field irradiation

A cobalt-60 therapy unit designed and constructed by The Ontario Cancer Institute is described. This unit is capable of treating large fields up to 50 × 160 cm² at a conventional source to surface distance of 90 cm by using large collimator openings. Three selectable filters were incorporated. They all act as electron filters to improve the build-up characteristics of these beams. Two of the three filters also act as beam flatteners. The longitudinal collimators are individually driven so that it is possible to produce a vertical beam edge by closing one of the collimators completely. This condition is very useful for matching adjacent fields. The output of this unit, at its operating distance, ranges from 100–200 rad/min depending on which of the filters is chosen, which makes the treatment time shorter than most known facilities for very large field irradiation. This unit has been in routine use since 1977.     

External Beam Radiotherapy in Western Africa: 1969–2019

AimsWe describe the absolute and per capita numbers of megavoltage radiotherapy machines (MVMs) in Western Africa from 1969 to 2019.Materials and methodsWestern Africa was defined in accordance with the United Nations' delineation and inclusive of 16 countries. A literature search for publications detailing the number of cobalt-60 machines (COs) and linear accelerators (LINACs) in radiotherapy centres was carried out. Population data from the World Bank Group and crude cancer rates from the International Agency for Research on Cancer were used to calculate ratios of million persons per MVM and MVMs per 1000 cancer cases.ResultsThe numbers of MVMs in Western Africa in 1969, 1979, 1989, 1999 and 2009 were zero, two, three, six and nine, respectively. In 2019 there were 22 MVMs distributed across Ghana (five), Côte d’Ivoire (two), Mali (one), Mauritania (two), Nigeria (nine) and Senegal (three). Nine countries (56.3%) had no history of external beam radiotherapy (EBRT). The largest increase in absolute EBRT capacity occurred from 2017 to 2019, during which 13 MVMs were commissioned. The largest decrease in EBRT capacity occurred from 2015 to 2017, during which four LINACs and three COs were rendered non-operational. The ratio of million persons per MVM improved from 67.0 in 1979 to 17.8 in 2019. As of 2019, there was 0.09 MVM per 1000 cancer cases.ConclusionsWestern African nations have experienced an increase in the absolute number of MVMs and per capita radiotherapy capacity during the last 50 years, especially in the last decade. As non-functional LINACs contributed to a temporary decline in the EBRT infrastructure, dual use of CO/LINAC technologies may act to promote the availability of EBRT treatment in centres with capacity for multiple MVMs.     

Comparative Analysis of Radiotherapy Linear Accelerator Downtime and Failure Modes in the UK,Nigeria and Botswana

The lack of radiotherapy linear accelerators (linacs) in low- and middle-income countries (LMICs) has been recognised as a major barrier to providing quality cancer care in these regions, together with a shortfall in the number of highly qualified personnel. It is expected that additional challenges will be faced in operating precise, high-technology radiotherapy equipment in these environments, and anecdotal evidence suggests that linacs have greater downtime and higher failure rates of components than their counterparts in high-income countries. To guide future developments, such as the design of a linac tailored for use in LMIC environments, it is important to take a data-driven approach to any re-engineering of the technology. However, no detailed statistical data on linac downtime and failure modes have been previously collected or presented in the literature. This work presents the first known comparative analysis of failure modes and downtime of current generation linacs in radiotherapy centres, with the aim of determining any correlations between linac environment and performance. Logbooks kept by radiotherapy personnel on the operation of their linac were obtained and analysed from centres in Oxford (UK), Abuja, Benin, Enugu, Lagos, Sokoto (Nigeria) and Gaborone (Botswana). By deconstructing the linac into 12 different subsystems, it was found that the vacuum subsystem only failed in the LMIC centres and the failure rate in an LMIC environment was more than twice as large in six of the 12 subsystems compared with the high-income country. Additionally, it was shown that despite accounting for only 3.4% of the total number of faults, linac faults that took more than 1 h to repair accounted for 74.6% of the total downtime. The results of this study inform future attempts to mitigate the problems affecting linacs in LMIC environments.     

The development of a provincial radiation oncology service: The first year report and its implications for future developments

This study compares the actual first year's workload of a new radiation oncology department with that predicted, and assesses the impact of the differences, and their implications for future similar developments. The treatment records and diaries for the Geelong Hospital Radiation Oncology Department were reviewed after the first 12 months of operation (opened in June 1992). Statistics relating to the number of patients seen, number treated, diagnosis, etc., were evaluated and compared to the original estimates based upon population statistics and likely referral rates. Nine hundred and seven new patients were seen in this period, and from them 718 courses of treatment were initiated. One hundred and eighty-nine cases (20% of referrals) were seen but not treated. A further 102 treatment courses (14% of total) were initiated upon patients who had previously been irradiated. Forty-six per cent of patients were managed by 10 fractions or fewer, and a further 23% by 25 or more fractions. Eighty per cent of patients were managed by one or two fields. Electrons were used in only 14% of cases. Further calculations suggested a further possible 441 cases of referral could be expected, based upon current population statistics. Referral rates for radiation oncology are highly dependent on a number of factors. As a result, estimates of referrals and hence the size of a department required for a given population vary widely. Our data support these concepts, and the concept that referral is also strongly dependent upon the distance patients need to travel. In considering the development of units outside of major cities it is suggested that referrals are likely to be on the high side of estimates and a minimum two-machine unit is essential to cover the given workload.     

Late effects of 50 McVd→Be neutron and cobalt-60 irradiation of rhesus monkey cervical spinal cord

The cervical spinal cords of 30 rhesus monkeys were irradiated with 50 MeV_d→Be neutrons or ⁶⁰Co gamma rays to evaluate the dose-response relationships for radiation myelopathy. Three groups were treated with 50 MeV_d→Be neutrons using dosage schedules of 1300 rad_mγ (Group I), 1425 rad_mγ (Group II), or 1550 rad_mγ (Group III) in nine fractions over 29 days. Three groups were irradiated with ⁶⁰Co gamma rays using dosage schedules of 4620 rad_mγ (Group IV), 5390 rad_mγ (Group V), or 5940 rad_mγ (Group VI) in 22 fractions over 29 days. A significant dose-response relationship was observed for the groups treated with neutrons. Whereas none of the monkeys in Group I showed clinical evidence of neurologic dysfunction, all five animals in Group III became paralyzed. One animal in Group II developed transient neck stiffness and mild unilateral leg paresis. No definitive signs of neurologic injury were seen in any of the animals irradiated with ⁶⁰Co. The histopathologic changes correlated well with the clinical observations. All of the animals in Group III exhibited moderate to severe malacia and demyelination of the white matter of the cervical spinal cord. The histologic data indicated that the RBE for five times weekly fractionation (～270 rad_mγ⁶⁰Co. fractions) was in the range of 4.2 to 4.6, since the malacia and demyelination in the spinal cords irradiated with 5940 rad_mγ of ⁶⁰Co. γ-rays were greater than that observed in the spinal cords irradiated with 1300 rad_mγ of neutrons but less than the changes in those irradiated with 1425 rad_mγ of neutrons.     

60例胸段食管癌后程加速超分割放射治疗分析

[目的]评价食管癌后程加速超分割放射治疗疗效及并发症.[方法]60例食管癌随机分为2组:常规分割组30例,1次/天,2Gy/次,5次/周,总剂量65Gy,32.5分次,6.5～7周完成;后程加速超分割组30例,1次/天,2Gy/次,5次/周,总剂量达40Gy,20分次后改为2次/天,1.5Gy/次,10次/周,总剂量65Gy,36.6分次,5～6周.[结果]两组1、3、5年局部控制率后程加速超分割组优于常规分割组(P＜0.05),分别为70.0%、53.3%、46.6%和56.6%、36.6%、30%;1、3、5年生存率后程加速超分割组优于常规分割组(P＜0.05),分别为73.3%、36.3%、30.0%和60.0%、26.6%、20.0%.后程加速超分割组急性反应发生率较常规分割组高,但差异无显著性(P＞0.05).[结论]食管癌后程加速超分割放疗能明显提高局部控制率和生存率,不明显增加放射治疗反应及并发症.     

局部晚期非小细胞肺癌调强放疗与三维适形放疗的剂量学及临床疗效分析

[目的]分析比较局部晚期非小细胞肺癌（NSCLC）调强放疗（IMRT）与三维适形放疗（3D-CRT）的临床疗效及对靶区和危及器官的剂量学差异。[方法]回顾性分析局部晚期非小细胞肺癌102例,其中52例采用3D-CRT,50例采用IMRT治疗,处方剂量PTV：56~64Gy/28~33次,比较两组的临床疗效和不良反应。选择其中10例患者的CT定位图像,分别设计IMRT和3D-CRT计划,给予DT：64Gy/32f照射,用剂量体积直方图（DVH）评价2种治疗计划的靶区和危及器官的剂量参数。[结果]10例IMRT计划中肺的V20、V30及肺平均剂量低于3D-CRT,而V5高于3D-CRT计划（P〈0.05）,V10无差异（P〉0.05）。IMRT的靶区适形指数（CI）和靶区均匀指数（HI）均优于3D-CRT（P〈0.05）,IMRT计划中脊髓的最大剂量（Dmax）较3D-CRT低（P〈0.05）。IMRT组与3DCRT组的1、2、3年生存率分别为82.0%、46.0%、28.0%和76.9%、36.5%、19.2%,中位生存期分别为22个月和18个月（P〉0.05）,1、2、3年无进展生存率分别为70.0%、34.0%、16.0%和63.5%、25.0%、9.6%,中位PFS分别为18个月和16个月（P〉0.05）。同步放化疗患者1、2、3年总生存率、无进展生存率分别为90.5%、71.4%、47.6%和85.7%、52.3%、33.3%,与序贯化放疗相比有显著性差异（P〈0.05）。IMRT组与3D-CRT组的近期疗效分别为76.0%、55.8%（P〈0.05）,急性放疗反应发生率两组无显著性差异。[结论]调强放射治疗可提高非小细胞肺癌近期疗效,调强放射治疗的计划可以提高靶区的适形度和均匀性,同时降低危及器官的剂量。     

Curative-Intent Radiotherapy for Squamous Cell Carcinoma of the Head and Neck in Sri Lanka: The Impact of Radiotherapy Technique on Survival

AimsWe conducted a retrospective analysis of patients with squamous cell carcinoma of the head and neck (SCCHN) treated with curative-intent radiotherapy at the National Cancer Institute of Sri Lanka to determine the impact of the treatment technique on disease-free survival (DFS).Materials and methodsSCCHN patients treated with radical radiotherapy or adjuvant postoperative radiotherapy from 2016 to 2017 were included in the study. Data on the following variables were collected by reviewing clinical and radiotherapy treatment records: age, gender, tumour site, stage, time to delivery of radiotherapy, use of neoadjuvant chemotherapy, use of concurrent radiosensitising chemotherapy and treatment technique. DFS, defined as the time to death, tumour recurrence or loss to follow-up, was the primary end point and outcomes were compared between patients treated with intensity-modulated radiotherapy (IMRT) in linear accelerators and those treated with conventional radiotherapy in cobalt teletherapy units. Univariate and multivariate analyses were carried out on known prognostic variables.ResultsIn total, 408 patients were included in the study, with 138 (34%) being treated with IMRT in the linear accelerator. More than 75% of patients were of stage III or IV at diagnosis. The 2-year DFS of the whole cohort was 25% (95% confidence interval 21–30%). Patients treated with IMRT in the linear accelerator had a superior DFS in comparison with those treated with conventional radiotherapy in the cobalt teletherapy units (P < 0.001, hazard ratio 0.64, 95% confidence interval 0.5–0.82). Higher stage, cobalt treatment and use of neoadjuvant chemotherapy were adversely associated with DFS on multivariate analysis.ConclusionA large proportion of patients with SCCHN treated with curative-intent radiotherapy in Sri Lanka had locally advanced disease and DFS was superior in patients treated with IMRT in the linear accelerator.     

The Development of Therapeutic Radiographers in Imaging and Adaptive Radiotherapy Through Clinical Trial Quality Assurance

AimsAdaptive radiotherapy (ART) is an emerging advanced treatment option for bladder cancer patients. Therapeutic radiographers (RTTs) are central to the successful delivery of this treatment. The purpose of this work was to evaluate the image-guided radiotherapy (IGRT) and ART experience of RTTs before participating in the RAIDER trial. A plan of the day (PoD) quality assurance programme was then implemented. Finally, the post-trial experience of RTTs was evaluated, together with the impact of trial quality assurance participation on their routine practice.Materials and methodsA pre-trial questionnaire to assess the experience of the RTT staff group in IGRT and ART in bladder cancer was sent to each centre. Responses were grouped according to experience. The PoD quality assurance programme was implemented, and the RAIDER trial commenced. During stage 1 of the trial, RTTs reported difficulties in delivering PoD and the quality assurance programme was updated accordingly. A follow-up questionnaire was sent assessing experience in IGRT and ART post-trial. Any changes in routine practice were also recorded.ResultsThe experience of RTTs in IGRT and ART pre-trial varied. For centres deemed to have RTTs with more experience, the initial PoD quality assurance programme was streamlined. For RTTs without ART experience, the full quality assurance programme was implemented, of which 508 RTTs completed. The quality assurance programme was updated (as the trial recruited) and it was mandated that at least one representative RTT (regardless of pre-trial experience) participated in the update in real-time. The purpose of the updated quality assurance programme was to provide further support to RTTs in delivering a complex treatment. Engagement with the updated quality assurance programme was high, with RTTs in 24/33 centres participating in the real-time online workshop. All 33 UK centres reported all RTTs reviewed the updated training offline. Post-trial, the RTTs' experience in IGRT and ART was increased.ConclusionOverall, 508 RTTs undertook the PoD quality assurance programme. There was a high engagement of RTTs in the PoD quality assurance programme and trial. RTTs increased their experience in IGRT and ART and subsequently updated their practice for bladder cancer and other treatment sites.