How to perform brain surgery without making a single cut - Hyunsoo Joshua No

翻译人员: Michael LV吕 校对人员: Yolanda Zhang

Every year, tens of thousands of people world-wide have brain surgery

每年，全世界有 成千上万的人接受了

without a single incision:

无创的脑部手术：

there’s no scalpel, no operating table, and the patient loses no blood.

没有手术刀，没有手术台， 病人不会失血。

Instead, this procedure takes place in a shielded room

这种手术是在一个 屏蔽室里进行的，

with a large machine that emits invisible beams of light

里面有一台大型机器， 它会向大脑内部的精确目标

at a precise target inside the brain.

发射不可见的光束。

This treatment is called stereotactic radiosurgery,

这种治疗叫做 立体定向放射治疗,

and those light beams are beams of radiation:

这些光束是辐射束:

their task is to destroy tumors by gradually scrubbing away malignant cells.

它们会逐渐清除恶性细胞， 最终消灭肿瘤。

For patients, the process begins with a CT-scan,

对于病人来说， 这个手术始于 CT 扫描,

a series of x-rays that produce a three-dimensional map of the head.

就是通过照射一系列的 X 射线 产生头部的三维成像。

This reveals the precise location, size, and shape of the tumor within.

CT 扫描能显示出肿瘤的 精确位置、大小，以及形状。

The CT-scans also help to calculate something called "Hounsfield Units,"

它还可以计算一种叫做 “亨氏单位（Hounsfield Units）”的指标，

which show the densities of different tissues.

亨氏单位能显示 不同组织的密度，

This offers information about how radiation

揭示辐射如何

will propagate through the brain, to better optimize its effects.

在大脑中传播， 以更好地发挥作用。

Doctors might also use magnetic resonance imaging, or MRI’s,

医生也可以使用 磁共振成像（MRI），

that produce finer images of soft tissue,

它能产生更清晰的软组织图像，

to assist in better outlining a tumor’s shape and location.

以便于更好地概述 肿瘤的形状和位置。

Mapping its precise position and size is crucial

绘制出肿瘤的精确位置和大小 是至关重要的，

because of the high doses of radiation needed to treat tumors.

因为治疗肿瘤 需要高剂量的辐射。

Radiosurgery depends on the use of multiple beams.

放射治疗依赖于 多束射线的作用。

Individually, each delivers a low dose of radiation.

每一束都能单独产生低剂量的辐射。

But, like several stage lights converging on the same point

但是，就像几盏舞台灯光 汇聚在同一点上

to create a bright and inescapable spotlight, when combined,

会变成一个明亮的、 惹眼的聚光灯一样，

the rays of radiation collectively produce enough power to destroy tumors.

辐射的射线聚集在一起 能够产生足够的能量来摧毁肿瘤。

In addition to enabling doctors to target tumors in the brain

除了能使医生瞄准 大脑中的肿瘤，

while leaving the surrounding healthy tissue relatively unharmed,

同时使周围的健康组织 相对不受伤害之外，

the use of multiple beams also gives doctors flexibility.

多光束的使用 也给了医生提供了灵活性。

They can optimize the best angles and routes through brain tissue

他们可以优化 光束通过脑组织到达目标的

to reach the target and adjust the intensity within each beam

最佳角度和路径，并根据需要

as necessary.

调整每个光束的强度。

This helps spare critical structures within the brain.

这有助于避开大脑中的关键结构。

But what exactly does this ingenious approach do to the tumors in question?

但这种独特方法对肿瘤 到底有什么作用呢？

When several beams of radiation intersect to strike a mass of cancerous cells,

当几束辐射交汇， 并射向一团癌细胞，

their combined force essentially shears the cells’ DNA,

它们会合力切断 细胞的 DNA，

causing a breakdown in the cells’ structure.

导致细胞结构遭到破坏。

Over time, this process cascades into destroying the whole tumor.

随着时间的推移，这一系列 连锁的过程会摧毁整个肿瘤。

Indirectly, the rays also damage the area immediately surrounding the DNA,

射线也会间接破坏 DNA 周围的区域，

creating unstable particles called free radicals.

产生不稳定的粒子， 我们称之为自由基。

This generates a hazardous microenvironment

这就产生了一种 有害的微环境，

that’s inhospitable to the tumor,

这种微环境对肿瘤

as well as some healthy cells in the immediate vicinity.

以及附近的一些健康细胞 都是不利的。

The risk of harming non-cancerous tissue is reduced

通过保持辐射束的覆盖范围

by keeping the radiation beam coverage

尽可能接近肿瘤的确切形状，

as close to the exact shape of the tumor as possible.

可以降低伤害非癌组织的风险。

Once radiosurgery treatment has destroyed the tumor’s cells,

一旦放射外科治疗 摧毁了肿瘤细胞，

the body’s natural cleaning mechanism kicks in.

身体的自然清理机制 就会开始发挥作用。

The immune system rapidly sweeps up the husks of dead cells

免疫系统开始迅速 清理死细胞的外壳，

to flush them out of the body, while other cells transform into scar tissue.

将它们排出体外， 而其他细胞则会转化为疤痕组织。

Despite its innovations, radiosurgery isn’t always the primary choice

尽管放射治疗有其创新之处， 但它在所有的脑癌治疗中

for all brain cancer treatments.

并非总是首选方案。

For starters, it’s typically reserved for smaller tumors.

首先，它通常被用来 对付较小的肿瘤。

Radiation also has a cumulative effect,

其次，辐射也具有累积效应，

meaning that earlier doses can overlap with those delivered later on.

这就意味着，早期的辐射剂量 可能与后来的辐射剂量叠加。

So patients with recurrent tumors

因此，肿瘤复发的病人

may have limitations with future radiosurgery treatments.

在未来的放射外科治疗中 可能面临着局限性。

But these disadvantages weigh up against some much larger benefits.

尽管存在着这些缺点， 但放射治疗的优势依然非常明显。

For several types of brain tumors,

对于几种类型的脑瘤，

radiosurgery can be as successful as traditional brain surgery

放射治疗也可以 和传统的脑部手术一样

at destroying cancerous cells.

成功地消灭癌细胞。

In tumors called meningiomas, recurrence is found to be equal, or lower,

在被称为脑膜瘤的肿瘤中， 患者接受放射治疗的复发率

when the patient undergoes radiosurgery.

与手术相当，甚至更低。

And compared to traditional surgery—

和传统手术相比——

often a painful experience with a long recovery period—

手术通常是一段需要 漫长恢复期的痛苦经历——

radiosurgery is generally pain-free,

而放射治疗通常是无痛的，

and often requires little to no recovery time.

通常几乎 不需要恢复时间。

Brain tumors aren’t the only target for this type of treatment:

脑瘤并不是放疗的唯一用途：

its concepts have been put to use on tumors of the lungs, liver, and pancreas.

它的概念已经应用于 肺、肝和胰腺的肿瘤。

Meanwhile, doctors are experimenting with using it to treat conditions

与此同时，医生们正在试验 用它来治疗其他疾病，

such as Parkinson’s disease, epilepsy, and obsessive compulsive disorder.

比如帕金森病、癫痫， 还有强迫症。

The pain of a cancer diagnosis can be devastating,

诊断出癌症带来的痛苦 可能是撕心裂肺的,

but advancements in these non-invasive procedures

但这些非侵入性 治疗技术的进步

are paving a pathway for a more gentle cure.

也为更温和的治疗手段 铺平了道路。