[Health Science] What exactly is the positioning of radiotherapy in patients with head and neck tumors?

Date：2023-11-01
Click：5737Times

Radiotherapy has now entered the era of precision, especially for patients with head and neck tumors, and most of them can be recovered or cured after intensity-modulated radiotherapy. For those who need radiotherapy, the radiotherapist will tell you during the conversation that the first step needs to be radiotherapy localization, and after the localization is finished, you have to wait for a few days before you can have radiotherapy.

So what is radiotherapy positioning? What do I need to pay attention to when positioning for radiotherapy? Why can't radiotherapy be given immediately after localization? Today we will learn about some of the problems related to radiotherapy localization.

What is radiotherapy localization?

Radiotherapy positioning is the reconstruction of the patient's body model structure by CT scanning, and the location of the tumor is shown by imaging in the CT coordinate system, in order to prepare for the implementation of the radiotherapy plan at a later stage. Let's take a look at the whole radiotherapy process.

Radiotherapy Procedure

Radiotherapy positioning has a special CT simulation positioning machine, positioning before the need to make a head mold or head, neck and shoulder mold, the role is to fix the radiotherapy site, prevent involuntary body movement, so that each treatment position to maintain the same. The new mold needs to be heated in a constant temperature water tank, and then softened and elasticized after taking it out, and then put it on the part of the patient that needs radiotherapy to be shaped, and then cooled down and shaped, so that every time the patient has radiotherapy in the future, he will be fixed with the same mold, which can reduce the error of radiotherapy.

CT simulation positioning using a laser line in the mold body or the patient's skin to draw a reference marking line, usually draw three "+" line, respectively located in the head and neck of the two sides and the position of the center. If the marking line becomes faded, contact the physician in charge to make up for it, and do not draw it yourself or ignore it. After positioning, the radiotherapy technician will transfer the CT images to the radiotherapy planning system, and the doctor will outline the extent of the tumor and the normal tissues and organs that should be avoided in order to avoid damage to these areas during radiotherapy.

At the end of the outline the radiotherapy plan is made by the physicist within the radiotherapy planning system, a process that we can understand by how the X-rays work to satisfy the irradiation of the tumor. After the completion of the intensity-modulated radiotherapy plan, it needs to be confirmed by both the radiotherapist and the physicist, and finally the accuracy of the plan in terms of dose and position has to be verified before radiotherapy can be started.

Anyway, there's a lot of behind-the-scenes work we have to do once the positioning is done for the accuracy of the radiotherapy plan, so be patient!

（供稿|肿瘤放疗科徐华）

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