Background:
Historically, radiation therapy for liver cancer was not widely used due to the high radiation sensitivity of the surrounding normal liver parenchyma and the difficulty of treatment due to internal organ movement. However, as it becomes possible to irradiate a tumor with sufficient radiation dose while protecting normal liver tissue, radiation therapy has increased indications for multiple stages of liver cancer in recent years. Various methods have been developed and applied in clinical practice to overcome geometric uncertainty in radiotherapy due to liver location variation and to provide accurate treatment. However, there are no studies on the relationship between liver tumor location movement and physiological changes such as stomach volume.

Hypothesis:
As the volume of the stomach increases, it will press on other internal organs and, as a result, raise the position of the liver toward the head. If gas is removed from the gastrointestinal tract by fasting or simethicone, it will be possible to minimize liver movement between radiation treatments by keeping the stomach volume uniform to a minimum.
In image-guided radiation therapy, it is thought that the appropriate radiation field margin will be smaller than that of general radiation therapy.

Objective:
During image-guided radiation therapy for liver cancer, stomach volume variability may affect liver location variability, leading to inaccurate treatment. 
The purpose of this study is to investigate whether gas removal with simethicone can reduce liver location variability between radiation treatments and to suggest an appropriate margin for the treatment field in respiratory-gated radiation therapy for liver cancer.

Method:
In the case of the simethicone group, from 3 days before the simulation treatment to the end of the radiation therapy, continuously take the simethicone ( 66.6mg, 3 times a day) 30 minutes after meals orally

The patient is trained to breathe more regularly and shallowly through a real-time position management system. The patient breathes while watching the graph change over time displayed on a portable media player placed over the head to increase the reproducibility of breathing.

A marker with two infrared reflectors is placed on the abdominal position on the patient and the infrared camera detects the reflected infrared as a respiratory signal to record the movement of the marker.

Select a 40-60% step (end of exhalation) as a gating window. The final exhalation phase is usually chosen for gating because there is little residual motion during this phase. Treatment planning is performed at 50% steps of the 4D CT data set.

Tumor volumes shown on CT, magnetic resonance imaging (MRI) and/or positron emission tomography (PET)/CT are set as total tumor volume (GTV) without extension to clinical target volume (CTV).

Radiation therapy is irradiated with a 6MV or 15MV photon beam from a linear accelerator. Prior to each treatment, validation was performed by both cone-beam (CB) CT scans and OBI kV image taken at 50% and 0% of respiration.

Comparing the CBCT image with the planned reference image of the 50% 4D CT image confirmed that the patient's bone structure and liver contours were close to the planned position. Orthographic OBI kV images (AP and lateral views) were taken at 50% and 0% of the respiratory cycle. Comparison of the right diaphragm contours seen in the OBI kV images at 50% and 0% of the respiratory cycle with digitally reconstructed radiographic images of the right diaphragm depicted at 50% and 0% of the planned 4D CT set, respectively.

Stomach volume setting and volume measurement are performed on CT image and CBCT images obtained during each treatment

 Supportive Care

The study design of the Experimental and the control group is identical except for the difference in the absence of simethicone.

In the case of the simethicone group, from 3 days before the simulation treatment to the end of the radiation therapy, continuously take the simethicone ( 66.6mg, 3 times a day) 30 minutes after meals orally

The patient is trained to breathe more regularly and shallowly through a real-time position management system. The patient breathes while watching the graph change over time displayed on a portable media player placed over the head to increase the reproducibility of breathing.

A marker with two infrared reflectors is placed on the abdominal position on the patient and the infrared camera detects the reflected infrared as a respiratory signal to record the movement of the marker.

Select a 40-60% step (end of exhalation) as a gating window. The final exhalation phase is usually chosen for gating because there is little residual motion during this phase. Treatment planning is performed at 50% steps of the 4D CT data set.

Tumor volumes shown on CT, magnetic resonance imaging (MRI) and/or positron emission tomography (PET)/CT are set as total tumor volume (GTV) without extension to clinical target volume (CTV).

Radiation therapy is irradiated with a 6MV or 15MV photon beam from a linear accelerator. Prior to each treatment, validation was performed by both cone-beam (CB) CT scans and OBI kV image taken at 50% and 0% of respiration.

Comparing the CBCT image with the planned reference image of the 50% 4D CT image confirmed that the patient's bone structure and liver contours were close to the planned position. Orthographic OBI kV images (AP and lateral views) were taken at 50% and 0% of the respiratory cycle. 
Comparison of the right diaphragm contours seen in the OBI kV images at 50% and 0% of the respiratory cycle with digitally reconstructed radiographic images of the right diaphragm depicted at 50% and 0% of the planned 4D CT set, respectively.

Stomach volume setting and volume measurement are performed on CT image and CBCT images obtained during each treatment.

Arm Label

Target Number of Participant

Arm Type

Arm Description

In the case of the simethicone group, from 3 days before the simulation treatment to the end of the radiation therapy, continuously take the simethicone ( 66.6mg, 3 times a day) 30 minutes after meals orally

The patient is trained to breathe more regularly and shallowly through a real-time position management system. The patient breathes while watching the graph change over time displayed on a portable media player placed over the head to increase the reproducibility of breathing.

A marker with two infrared reflectors is placed on the abdominal position on the patient and the infrared camera detects the reflected infrared as a respiratory signal to record the movement of the marker.

Select a 40-60% step (end of exhalation) as a gating window. The final exhalation phase is usually chosen for gating because there is little residual motion during this phase. Treatment planning is performed at 50% steps of the 4D CT data set.

Tumor volumes shown on CT, magnetic resonance imaging (MRI) and/or positron emission tomography (PET)/CT are set as total tumor volume (GTV) without extension to clinical target volume (CTV).

Radiation therapy is irradiated with a 6MV or 15MV photon beam from a linear accelerator. Prior to each treatment, validation was performed by both cone-beam (CB) CT scans and OBI kV image taken at 50% and 0% of respiration.

Comparing the CBCT image with the planned reference image of the 50% 4D CT image confirmed that the patient's bone structure and liver contours were close to the planned position. Orthographic OBI kV images (AP and lateral views) were taken at 50% and 0% of the respiratory cycle. Comparison of the right diaphragm contours seen in the OBI kV images at 50% and 0% of the respiratory cycle with digitally reconstructed radiographic images of the right diaphragm depicted at 50% and 0% of the planned 4D CT set, respectively.

Stomach volume setting and volume measurement are performed on CT image and CBCT images obtained during each treatment.

Arm Label

Target Number of Participant

Arm Type

Arm Description

In the case of the control group, The patient is trained to breathe more regularly and shallowly through a real-time position management system. The patient breathes while watching the graph change over time displayed on a portable media player placed over the head to increase the reproducibility of breathing.

A marker with two infrared reflectors is placed on the abdominal position on the patient and the infrared camera detects the reflected infrared as a respiratory signal to record the movement of the marker.

Select a 40-60% step (end of exhalation) as a gating window. The final exhalation phase is usually chosen for gating because there is little residual motion during this phase. Treatment planning is performed at 50% steps of the 4D CT data set.

Tumor volumes shown on CT, magnetic resonance imaging (MRI) and/or positron emission tomography (PET)/CT are set as total tumor volume (GTV) without extension to clinical target volume (CTV).

Radiation therapy is irradiated with a 6MV or 15MV photon beam from a linear accelerator. Prior to each treatment, validation was performed by both cone-beam (CB) CT scans and OBI kV image taken at 50% and 0% of respiration.

Comparing the CBCT image with the planned reference image of the 50% 4D CT image confirmed that the patient's bone structure and liver contours were close to the planned position. Orthographic OBI kV images (AP and lateral views) were taken at 50% and 0% of the respiratory cycle. Comparison of the right diaphragm contours seen in the OBI kV images at 50% and 0% of the respiratory cycle with digitally reconstructed radiographic images of the right diaphragm depicted at 50% and 0% of the planned 4D CT set, respectively.

Stomach volume setting and volume measurement are performed on CT image and CBCT images obtained during each treatment.

Gender

Age

Description

Patients with liver cancer who are subject to image-guided and respiratory-gated radiation therapy 

Performance status : ECOG 0~1 patient

Liver function test : Child-pugh class A or some B patient

Patients who agreed to participate in the study

Liver function test : Child-pugh class C patient

Pregnant women, seniors over 80 years old, under 20 years old

Patients who have difficulty understanding or following the medical staff`s instructions for image-guided and respiratory-gated radiation therapy

Evaluation of liver and kidney dose in radiation therapy plan

180 day

Measurement of relative positional variation in orthogonal OBI kV images (AP and lateral views) taken at 50% and 0% of the respiratory cycle of each treatment

180 day

Stomach volume setting and volume measurement in CBCT performed before each treatment

180 day

Measurement of hepatic and kidney position variation in CBCT  performed before each treatment

180 day

Comparison of stomach volume and liver location variation according to whether of not simethicone was taken

180 day

Data on RT planning and treatment are collected through review of the Eclipse treatment planning system

180 day