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

譯者: Lilian Chiu 審譯者: Helen Chang

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

每年，全世界有數萬人接受

沒有任何切口的腦部手術：

without a single incision:

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

沒有解剖刀，沒有手術台，

病人也不會失血。

Instead, this procedure takes place in a shielded room

這項醫療程序改在隔離室進行，

with a large machine that emits invisible beams of light

裡面有一台大型機器， 發射看不見的光束，

at a precise target inside the brain.

精準射向大腦中的目標點。

This treatment is called stereotactic radiosurgery,

這項治療方式稱為立體定向手術，

and those light beams are beams of radiation:

那些光束則是放射線射束：

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

任務是漸漸除掉惡性細胞，

以摧毀腫瘤。

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

對病人而言，流程 始於電腦斷層掃瞄，

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

透過一連串 X 光， 產生出頭部的三維圖像，

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

呈現顱內腫瘤的 精確位置、大小，和形狀。

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

電腦斷層掃瞄也能協助計算

所謂的「韓森費爾德單位」，

which show the densities of different tissues.

這個值代表不同組織的密度。

This offers information about how radiation

這些資訊能協助判斷放射線

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

如何穿過大腦才會有最佳的效果。

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

醫生也可能使用磁振造影（MRI），

that produce finer images of soft tissue,

產生出更精細的軟組織影像，

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

協助將腫瘤的形狀 和位置描繪得更清楚。

Mapping its precise position and size is crucial

精確描繪腫瘤的位置和大小極其重要，

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

因為要用高劑量的 放射線來治療腫瘤。

Radiosurgery depends on the use of multiple beams.

放射手術需要使用多條射束，

Individually, each delivers a low dose of radiation.

每一條各是低劑量的放射線束。

But, like several stage lights converging on the same point

但就如同舞台上的多重光源 聚焦於同一個點，

to create a bright and inescapable spotlight, when combined,

以產生出明亮、不亂竄的聚光燈，

放射線通通加疊在一起

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

共同產生足以摧毀腫瘤的力量。

In addition to enabling doctors to target tumors in the brain

除了能讓醫生在相對不傷害

while leaving the surrounding healthy tissue relatively unharmed,

周圍健康組織的情況下 對付腦中的腫瘤之外，

the use of multiple beams also gives doctors flexibility.

多重射束的使用也讓醫生保有彈性，

They can optimize the best angles and routes through brain tissue

他們可以找出放射線穿過腦部組織

抵達目標的最佳角度和路線，

to reach the target and adjust the intensity within each beam

並根據需求調整每條射束的強度，

as necessary.

This helps spare critical structures within the brain.

這麼做便能避免傷害 腦部的重要結構。

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

但這種巧妙的方法 對目標腫瘤到底有什麼作用？

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

當數條放射線射束交會

攻擊癌細胞聚集處時，

their combined force essentially shears the cells’ DNA,

它們結合起來的力量 基本上會切斷細胞的 DNA，

causing a breakdown in the cells’ structure.

造成細胞的結構受損。

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

隨時間重覆這個流程， 會漸漸將整個腫瘤摧毀。

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

射線也會間接傷害到 和目標 DNA 相鄰接的區域，

creating unstable particles called free radicals.

創造出不穩定的粒子，稱為自由基。

This generates a hazardous microenvironment

這會產生出一個有害的微環境，

that’s inhospitable to the tumor,

不適合腫瘤生長，

as well as some healthy cells in the immediate vicinity.

也不適合鄰接區域中的 一些健康細胞生長。

The risk of harming non-cancerous tissue is reduced

傷害非癌症組織的風險 之所以能被降低，

by keeping the radiation beam coverage

是因為放射線射束的覆蓋範圍

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

被控制在盡可能 和腫瘤的形狀完全一樣。

Once radiosurgery treatment has destroyed the tumor’s cells,

一旦放射手術治療 將腫瘤細胞摧毀之後，

the body’s natural cleaning mechanism kicks in.

身體的自然清理機制就會啟動。

The immune system rapidly sweeps up the husks of dead cells

免疫系統馬上就會 將死亡細胞的屍體清掉，

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

並排出體外，而其他細胞 則會轉變成疤痕組織。

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

儘管放射手術十分創新，

卻不見得是所有 腦部癌症治療的首選。

for all brain cancer treatments.

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

首先，放射手術會用來 治療較小的腫瘤。

Radiation also has a cumulative effect,

放射線也會有累加效應，

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

意即，先前的劑量可能會 和後來施予的劑量加疊。

So patients with recurrent tumors

所以，對於腫瘤復發的病人，

may have limitations with future radiosurgery treatments.

未來的放射手術治療就可能會受限。

But these disadvantages weigh up against some much larger benefits.

但這些弊處要拿來 和更重要的益處相比較。

For several types of brain tumors,

針對數種腦瘤，

radiosurgery can be as successful as traditional brain surgery

放射手術都有可能 和傳統腦部手術一樣

at destroying cancerous cells.

能成功摧毀癌症細胞。

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

就腦膜瘤而言，

若病人接受放射手術，

when the patient undergoes radiosurgery.

復發的機率和傳統一樣或更低。

And compared to traditional surgery—

和傳統手術相比——

often a painful experience with a long recovery period—

傳統手術通常是痛苦的經驗， 且時間復原很長——

radiosurgery is generally pain-free,

放射手術一般來說是無痛的，

and often requires little to no recovery time.

且需要的復原時間很短， 甚至可以立即復原。

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

這種治療不只能用在腦瘤上：

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

它的概念已經被用在 肺癌、肝癌，及胰臟癌上。

Meanwhile, doctors are experimenting with using it to treat conditions

同時，醫生也在實驗

用它來治療其他疾病，

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

如帕金森氏症、癲癇，及強迫症。

The pain of a cancer diagnosis can be devastating,

被診斷出罹癌或許是重創，

but advancements in these non-invasive procedures

但這些越來越進步的 非侵入性醫療手術

are paving a pathway for a more gentle cure.

正在為更柔和的治療方式舖路。