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Development of Chinese mesh-type pediatric reference phantom series and application in dose assessment of Chinese
Ruiyao Ma1,2,3, Rui Qiu1,3, Zhen Wu4
1Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.
Insights
New Chinese pediatric reference phantoms improve computed tomography (CT) dose accuracy. Using these phantoms significantly reduces dose calculation discrepancies for Chinese children undergoing CT scans.
Area of Science:
- Medical Physics
- Radiological Sciences
- Computational Biology
Background:
- Pediatric patients exhibit increased sensitivity to radiation due to higher cell division rates, necessitating accurate organ absorbed dose and effective dose assessments during computed tomography (CT) scans.
- Monte Carlo simulations with computational phantoms are standard for dose calculations in medical imaging and radiotherapy.
- Existing pediatric reference phantoms are predominantly based on Caucasian populations, limiting their accuracy for diverse pediatric demographics like Chinese children.
Observation:
- A series of Chinese pediatric reference phantoms were developed, encompassing ages from 3 months to 15 years (CRC3m, CRC01, CRC05, CRC10, CRCM15, CRCF15).
- These phantoms were applied to assess CT doses on a GE LightSpeed 16 CT scanner, establishing a CT dose database across various parameters (kVp, collimator width, filters).
- Comparison of results from the 1-year-old phantom (CRC01) with existing studies highlighted significant variations in dose calculations due to phantom characteristics.
Findings:
- Differences in phantom characteristics, organ masses, and positions substantially impact CT dose calculation outcomes.
- For organs fully within the X-ray beam, dose results using the CRC01 phantom showed less than 10% difference compared to other studies.
- For organs partially or not covered by the scan range, discrepancies reached up to 84% (stomach, chest exams) and 463% (gonads, chest exams).
Implications:
- The developed Chinese pediatric reference phantoms enable more accurate CT dose assessment for Chinese children.
- These phantoms can aid in optimizing radiation doses for pediatric CT examinations, enhancing patient safety.
- The developed phantom series has potential applications in dose estimation for other medical imaging modalities involving pediatric patients.
Abstract:
Pediatric patients are in a growing stage with more dividing cells than adults. Therefore, they are more sensitive to the radiation dose when undergoing computed tomography (CT) scanning. It is necessary and essential to assess the organ absorbed dose and effective dose to children. Monte Carlo simulation with computational phantoms is one of the most used methods for dose calculation in medical imaging and radiotherapy. Because of the vast change of the pediatric body with age increasing, many research groups developed series pediatric phantoms for various ages. However, most of the existing pediatric reference phantoms were developed based on Caucasian populations, which is not conformable to Chinese pediatric patients. The use of different phantoms can contribute to a difference in the dose calculation. To assess the CT dose of Chinese pediatric patients more accurately, we developed the Chinese pediatric reference phantoms series, including the 3-month (CRC3m), 1-year-old (CRC01), 5-year-old (CRC05), 10-year-old (CRC10), 15-year-old male (CRCM15), and a 15-year-old female (CRCF15) phantoms. Furthermore, we applied them to dose assessment of patients undergoing CT scanning. The GE LightSpeed 16 CT scanner was simulated and the paper presents the detailed process of phantoms development and the establishment of the CT dose database (with x-ray tube voltages of 120, 100 and 80 kVp, with collimators of 20, 10, and 5 mm width, with filters for head and body), compares for the 1-year-old results with other results based on different phantoms and analyzes the CT dose calculation results. It was found that the difference in phantoms' characteristics, organ masses and positions had a significant impact on the CT dose calculation outcomes. For the 1-year-old phantom, the dose results of organs fully covered by the x-ray beam were within 10% difference from the results of other studies. For organs partially covered and not covered by the scan range, the maximum differences came up to 84% (stomach dose, chest examinations) and 463% (gonads dose, chest examinations) respectively. The findings are helpful for the dose optimization of Chinese pediatric patients undergoing CT scanning. The developed phantoms could be applied in dose estimation of other medical modalities.
