Abstract: Objective To evaluate the association of radiation dose for high-tension and low-tension keloids and to explore the optimal radiotherapy. Methods Of the 48 patients, 25 had two keloids in high-tension parts such as anterior chest wall, scapulae and pubis, and 23 had two keloids in low-tension parts such as ear and neck. The patients were divided into two groups: high radiation dose group (group A) and low radiation dose group (group B). All patients received fractional CO₂ laser to remove the hypertrophic scar. After wound healing, patients in group A were treated with 7 Gy 3 times by ³²P applicator; patients in group B were treated with 5 Gy 3 times. The clinical efficacy and side effects were compared between the two groups. Results For low-tension parts: there were no significant differences between the two groups in cure rates and VSS scores (95.2% vs 80.9%, 5.21±0.78 vs 5.43±0.53, χ²=2.043, t=1.069, P>0.05). The ratio of side effects in group A was significantly higher than that in group B (71.4% vs 38.1%, χ²=4.709, P<0.05). For high-tension parts: the cure rate and VSS in group A were markedly higher than those in group B (75.0% vs 41.7%, 5.56±0.51 vs 6.96±0.71, χ²=5.486, t=7.846, P<0.05). Conclusion For better curative effects, keloids in low-tension parts should be treated with 15 Gy in 3 fractions, while keloids in high-tension parts should be treated with 21 Gy in 3 fractions.

Key words: Radiation dose, Keloid, Fractional laser, ³²P applicator, Tension