放射線治療の方法
放射線治療の方法には身体の外から放射線を照射する外部照射法と、放射線源を直接身体の組織や、食道、子宮といった腔に挿入して治療する密封小線源治療があります。どちらかひとつの放射線治療をすることもあれば、外部照射法と密封小線源治療を組み合わせて治療することもあります。最も多く行われている方法は外部照射法のみで行われる治療です。
非密封の放射性同位元素による治療についても簡単に記載します。
Approaches to radiotherapy include: EBRT (External Beam Radiation Therapy) that irradiates the body from the outside and sealed source radiotherapy, a treatment that irradiates tissues directly by inserting radiation into cavities like the esophagus and uterus. While there are treatments using only one method, there is also a therapy that combines both methods for treatment. The most widely used approach is the one in which EBRT is used solely for treatment.
I will also give a short summary in regards to unsealed radioisotope treatments.
There are two methods of radiation therapy: the external beam radiation therapy (or external beam radiotherapy), the brachytherapy (or sealed-source radiation therapy). The external beam radiation therapy delivers the radiation pointed at a particular part of the body, and the brachytherapy in which a radiation source is inserted into the body next to a tissue, and to cavum such as an esophagus and a uterus.
One of the radiotherapy can be used alone or in combination with each other. The most used method is the therapy only using the external beam radiotherapy.
This paper also includes the brief description of unsealed source radiotherapy.
外部照射法
外部照射法に使われている治療機器には、電子を加速してX線、電子線をとり出すリニアック、
マイクロトロンなどがあります。これらは高エネルギー治療装置といわれ、1960年代以降に普及してきました。それ以前は低いエネルギーのX線治療装置が主流でした。しかし、この治療装置では、身体の深いところにあるがんよりは表面の皮膚に高い線量となってしまい、がん病巣に対する線量が不十分なため、がんの治りが悪く、しかも強い皮膚炎が生じてしまいました。
Apparatus used for EBRT include: Microtron and Linear accelerators which use X rays to accelerate electrons and draw electron beams. These are called high energy treatment devices and started to become widespread by the 60's. Before that, low energy X ray treatment was mainly used, but such devices, rather than targeting visceral portions of the body where cancer is located, caused severe inflammation by concentrating to much radiation on the skin's surface while simultaneously not providing enough radiation to effectively treat cancer sites.
For the radiation therapy machines, there are a linear particle accelerator or LINAC and a microtron etc. which generate X-rays and high energy electros by accelerating the velocity of charged electrons.
These are called high energy radiation therapy machines and they have become widely used from the 1960s and onwards.
Before then, low energy radiation therapy machines were in the master stream; for these machines, however, the intensity of radiation on the skin became stronger than delivered to the tumor cells located deep inside of the body leading insufficient delivery of radiation to the cancer lesion: that caused poor cancer treatment and caused severe dermatitis.