[Dose distribution from kV-cone beam computed tomography in image-guided radiotherapy]
Tomohiro Kouno1, Fujio Araki, Yuji Nakaguchi
1Graduate School of Health Sciences, Kumamoto University.
Nihon Hoshasen Gijutsu Gakkai Zasshi
|July 24, 2013
Summary
Image-guided radiotherapy (IGRT) using kV-cone beam computed tomography (CBCT) increases patient dose. This study measured kV-CBCT dosimetry, finding doses vary by phantom and scan type, necessitating dose reduction for organs at risk.
Area of Science:
- Medical Physics
- Radiation Oncology
- Radiotherapy Dosimetry
Context:
- Image-guided radiotherapy (IGRT) adoption is rising.
- kV-cone beam computed tomography (CBCT) contributes to increased patient radiation dose.
- Accurate dosimetry is crucial for IGRT techniques.
Purpose:
- To investigate and quantify the absorbed dose delivered by kV-cone beam computed tomography (CBCT).
- To evaluate kV-CBCT dosimetry using established calibration methods and phantom studies.
- To compare kV-CBCT doses with other imaging techniques and scan protocols.
Summary:
- Absorbed dose measurements for kV-CBCT were performed using a Farmer ionization chamber and an I'mRT phantom.
- Monte Carlo simulations were used to determine beam quality conversion factors and ionization ratios.
- Doses for pelvis scans ranged from 2.5-4 cGy (kV-CBCT) and 4-8 cGy (MV-CBCT); head scans ranged from 0.1-0.7 cGy (kV-CBCT) and 3-5 cGy (MV-CBCT).
- Radiophotoluminescent glass dosimeter (RGD) measurements corroborated ion chamber findings.
Impact:
- Highlights the need to minimize radiation dose to organs at risk during IGRT procedures.
- Provides essential dosimetry data for optimizing kV-CBCT protocols.
- Informs clinical practice regarding the radiation burden associated with IGRT techniques.
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