Radiotherapy
September 2,2019 Update
Radiotherapy
With radiotherapy, there is an external irradiation treatment that radiates radiation from outside the body and brachytherapy that is irradiated from the inside. This is said to be one of the three major treatments for malignant tumors, along with surgery and chemotherapy. Radiotherapy equipment has been progressing exponentially in recent years and it has become possible to minimize the adverse effects and be low invasive.
In our hospital, we perform stand-alone radiation treatment or treatment in combination with surgery and chemotherapy. In addition, we cooperate closely with the attending doctor (or the referring original doctor) and perform the treatment.
Introduction to the treatment rooms
Our hospital performs treatment with two external irradiation treatment devices and one brachytherapy device.
External irradiation treatment
A linear accelerator (LINAC) is used to irradiate with high energy radiation (X-rays and electron beams) in medical radiation of the affected area. The outlet of the radiation is equipped with a mechanism called multi-leaf collimator (MLC) which can create a free shape using a lead block.
Treatment Room 2 TrueBeam
Multi-leaf Collimator (MLC)
| Treatment Room 1 | Treatment Room 2 | |
|---|---|---|
| Type | VARIAN, CLINAC21EX | VARIAN, TrueBeam |
| X-Ray (MV) | 6・10 | 4・6・8・10 |
| Electron Beam (MeV) | 6・9・12・16・20 | 6・9・12・15・16・18・20 |
| MLC | 60X | 60X |
(1) Stereotactic irradiation (special external irradiation treatment)
- "Brain Lesions"
-
The radiation is converged three-dimensionally from multiple directions for metastatic brain tumors and arteriovenous malformations (AVM) which can't adapt surgery. There is little effect on the surrounding normal tissue and a treatment effect equivalent to surgery can be expected. MRI imaging is performed, head securing masks are prepared, and CT imaging is used to make detailed plans in order to provide high-precision treatment.
The treatment period is from one day to several days, and one treatment time is about 30 minutes. - "Pulmonary tumors"
- This is an application of stereotactic radiation technology to lesions in the brain. This can apply to lung cancer and metastatic lung tumors. In our hospital, we perform high-precision treatment by using a fixture for respiratory control.
(2) Brachytherapy
Brachytherapy allows radiation to be concentrated in the affected area by directly attaching to the tumor site or piercing it with the radiation source, reducing the effect of radiation on normal tissues. These irradiation methods using brachytherapy are roughly divided into intracavity irradiation and interstitial irradiation. In our hospital, we use Iridium 192Ir as a radiation source to perform intracavity irradiation (cervical cancer) and interstitial irradiation (prostate cancer).
Brachytherapy Room
Micro Selectron HDR
(3) Intensity modulated radiation therapy
High-precision radiotherapy to match the shape of the tumor is carried out for the prostate to avoid the risk to organs such as the rectum.
Treatment Time (flow of treatment)
- Examination
When a radiologist examines a patient referred from the hospital or from outside, they will explain the need for radiation therapy such as the treatment policy (where the body will be irradiated, and how it will be irradiated) in an easy-to-understand manner. Please bring your referral letter and the image examination film, etc. necessary for treatment to the initial consultation.
- Reservations
After the medical examination and the description of the treatment have been completed by the radiologist, the specific treatment plan date and the treatment start date will be determined. The treatment will usually begin within one week after the examination. (However, the start of the irradiation may be one week or more after the examination for patients after surgery or in combination with chemotherapy, etc.)
- Radiation therapy plan (simulation)
Determine how to actually irradiate with the radiation and mark the body (skin surface). Our clinic uses a CT simulator to conduct treatment plans. The target range is imaged by the CT, and the radiologist determines the irradiation method based on the obtained image. The positional information is sent to a laser emitter as soon as the irradiation position is determined and the position is displayed on the body surface. A mark is drawn at that position with special ink. It takes about 20 minutes to complete the series of work, and then the treatment planning ends.
CT Simulator
CT image from which the position is determined and the positional information data are calculated using a three-dimensional treatment planning device (Xio), and the data is sent to the treatment device.
In our clinic, the entire series of cooperative steps from CT to planning and treatment equipment are done online.
- Treatment
The treatment is basically performed from two days after the treatment planning.
You will lie in a special bed for the treatment and we will accurately match the marks on the skin from the treatment plan. Since the LINAC records and matches the treatment method to the individual using computer management, we are able to do the same irradiation every time. The treatment time for 1 time is about 10 minutes.
- Return visits
After the radiotherapy, we will examine the course of radiotherapy periodically and check whether there is any reaction to the radiation therapy. Usually, you will come to the clinic once two weeks after the completion of irradiation.
