Cui Qinghao, Yan Xianrui, Li Chengqiang, Zhu Jian, Ma Jun, Liu Tingting
Linyi Hospital of Traditional Chinese Medicine, Department of Radiation Oncology Physics & Technology, Linyi, China.
Department of Engineering Physics, Tsinghua University, Beijing, China.
Thorac Cancer. 2025 Jun;16(12):e70102. doi: 10.1111/1759-7714.70102.
Image-guided radiation therapy uses imaging methods such as CBCT to effectively improve treatment precision. Kilovoltage-imaging technology provides high soft tissue contrast at low doses, whereas megavoltage-imaging technology better displays deep and bony structures at high doses. Proton therapy is more sensitive to tissue density and positional accuracy, so it requires more stringent image guidance and higher precision than traditional X-ray therapy.
This study evaluates radiation doses from CBCT systems (TrueBeam, Halcyon, ProBeam, TOMO) in both adult and pediatric phantoms, measuring dose variations and predicting secondary tumor risks using a radiobiological model.
Absorbed doses in organs of adult and pediatric phantoms were measured with OSLDs across imaging systems. The risk of secondary tumors was estimated using the BEIR VII model.
Halcyon 2.0 and TOMO's MV-level imaging systems showed significantly higher doses than KV-level systems. Pediatric patients received 2-3 times higher doses than adults. In KV-level imaging, Halcyon 2.0 resulted in the highest lung tissue dose in both age groups (17.464 mGy for pediatric, 9.109 mGy for adult), whereas ProBeam had the lowest (6.844 and 4.073 mGy, respectively). The lifetime attributable risk for lung cancer correlated with the dose, with higher risks in children.
Higher radiation doses lead to greater secondary tumor risk, with the risk being more pronounced in pediatric patients. Continuous thoracic CBCT can deliver up to 1 Gy in thoracic organs, posing a significant risk of secondary tumors, especially in younger patients. Careful consideration of this risk is essential in treatment planning.
图像引导放射治疗使用CBCT等成像方法有效提高治疗精度。千伏成像技术在低剂量下提供高软组织对比度，而兆伏成像技术在高剂量下能更好地显示深部和骨骼结构。质子治疗对组织密度和位置准确性更敏感，因此与传统X射线治疗相比，它需要更严格的图像引导和更高的精度。
本研究评估CBCT系统（TrueBeam、Halcyon、ProBeam、TOMO）在成人和儿童体模中的辐射剂量，使用放射生物学模型测量剂量变化并预测继发性肿瘤风险。
使用OSLDs在各成像系统中测量成人和儿童体模器官中的吸收剂量。使用BEIR VII模型估计继发性肿瘤的风险。
Halcyon 2.0和TOMO的兆伏级成像系统显示的剂量明显高于千伏级系统。儿科患者接受的剂量比成人高2至3倍。在千伏级成像中，Halcyon 2.0在两个年龄组中导致的肺组织剂量最高（儿科为17.464 mGy，成人为9.109 mGy），而ProBeam的剂量最低（分别为6.844和4.073 mGy）。肺癌的终身归因风险与剂量相关，儿童的风险更高。
更高的辐射剂量导致更大的继发性肿瘤风险，这种风险在儿科患者中更为明显。连续胸部CBCT可在胸部器官中产生高达1 Gy的剂量，带来显著的继发性肿瘤风险，尤其是在年轻患者中。在治疗计划中仔细考虑这种风险至关重要。
