2.Particle Beam Radiation Therapy Planning / Hyogo Ion Beam Medical Center


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Home＞What the Patient Needs to Know＞2.Particle Beam Radiation Therapy Planning

2.Particle Beam Radiation Therapy Planning

CT Imaging for Positioning

While the patient is in the posture to receive the particle beam radiation therapy, we perform a CT scan to take cross-section images of the focus area and its surroundings. These images become the key references for the particle beam radiation therapy planning.

【1】	On the CT scan table, the patient takes the posture to receive the radiation therapy and have the immobilization device attached.
【2】	First, we mark the center point of the CT scan on the immobilization device (marking).
【3】	We take CT images. Unlike with tests performed for diagnostic purposes, patients do not need to hold their breath.

If the focus area of the treatment is in the chest or abdomen (lungs, liver, etc.), this area moves with the patient's breathing. Therefore, we use a respiratory gating system and collect CT images only at moments when the patient exhales. The patient is breathing freely, but it appears on the CT images as though he/she is holding his/her breath. (In the actual radiation treatment, the particle beam will be irradiated only at moments when the patient exhales, using the same respiratory gating system).

【4】	For positioning, we sometimes take matching images of the patient's front and side.
【5】	For the same purpose, we sometimes perform MRI scans as needed.


Attaching Immobilization Device		Respiratory Sensor


CT Simulation		Respiratory Gating System

Particle Beam Radiation Therapy Planning

Using the CT images for positioning, a doctor evaluates the size and progression of the tumor and makes a prescription for the appropriate particle beam irradiation range, direction, and dose.

【1】	CT imaging does not always show the progression of the tumor clearly. If necessary, we perform overlapping (fusion) of MRI and CT imaging of the same area.
【2】	Based on the images, we specify the progression of the tumor and define the shape of the tumor on a computer. Taking into consideration errors caused by the patient's respiration and body movement, we determine the appropriate shape of the particle beam irradiation field. We also identify the organs that might develop side effects.
【3】	We determine the direction, energy, and depth of irradiation. Through a series of trials on the computer, we select the most effective therapy method that will minimize side effects.
【4】	Lastly, we save and output the treatment planning data.


Original CT Image for Positioning		Specifying Tumor Shape


2D Dose Distribution Curves		3D Dose Distribution Curves

Therapy Planning Conferences (Morning Conference / Afternoon Conference)

The therapy plan that has been created is reviewed in the next Morning Conference (attended by doctors, therapeutic radiation technologists, medical physicists, and nurses). If they find a problem, they re-do the radiation therapy planning. If the plan is approved, it is then submitted to the Afternoon Conference, where it is re-checked and reviewed by any hospital staff who missed the Morning Conference. Only after the plan is approved in the Afternoon Conference is the therapy plan transferred to the particle beam radiation therapy system.