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Published on: June 7, 2015
Effective doses in four-dimensional computed tomography for lung radiotherapy planning
Shinichiro Mori1, Susumu Ko, Takayoshi Ishii
1Research Center for Charged Particle Therapy Chiba, Japan. shinshin@nirs.go.jp
Summary
Four-dimensional computed tomography (4DCT) improves radiotherapy accuracy by reducing motion artifacts. However, 4DCT scans result in higher radiation exposure compared to helical CT, necessitating careful radiological protection optimization.
Area of Science:
- Medical Physics
- Radiotherapy Technology
- Radiation Dosimetry
Background:
- 4-D computed tomography (4DCT) is increasingly adopted in radiotherapy for precise tumor targeting.
- Minimizing respiratory motion artifacts is crucial for accurate treatment planning.
- Optimizing radiation exposure during 4DCT is essential for patient safety.
Purpose of the Study:
- To measure and analyze organ doses and effective dose from 4DCT scans.
- To compare radiation exposure between 4DCT and helical CT modes.
- To evaluate the radiological implications of 4DCT in radiotherapy.
Main Methods:
- Radiation exposure was measured using a 16 multidetector CT scanner.
- Organ doses were quantified using thermoluminescence dosimeter chips in an anthropomorphic phantom.
- Measurements were compared against helical CT scan protocols.
Main Results:
- The effective dose for 4DCT was measured at 24.7 mSv.
- This represents approximately a four-fold increase in radiation exposure compared to helical CT.
- Organ doses varied across anatomical sites, highlighting specific areas of higher exposure.
Conclusions:
- While 4DCT significantly enhances treatment accuracy in radiotherapy, it entails a higher radiation dose.
- The increased accuracy justifies the use of 4DCT, making its adoption inevitable.
- Understanding and managing patient exposure in 4DCT is vital for optimizing radiotherapy benefits.
