Biologically effective dose correlates with linear tumor volume changes after upfront single-fraction stereotactic radiosurgery for vestibular schwannomas

trigonocephalic shape, was used in this study.From the midpoint of the area of this section, half diagonals were calculated to the skull outline at 5 increments in the anterior half of the head.These half diagonals were used to create a sinusoidal curve, and the area under the sinusoidal curve (AUC) was used to represent the mathematical expression of the trigonocephalic head shape.The AUC from 0 to 180 (90 from the midline to each side) was calculated and is referred to as AUC 0→180 .The AUC from 60 to 120 (30 from the midline to each side) was also calculated and is referred to as AUC 60→120 .A total of 24 patients who underwent endoscopic strip craniectomy and 13 age-and sex-matched controls were included in the study.The AUC values obtained in patients at different time points and controls were analyzed.Results: The mean preoperative AUC 60→120 and AUC 0→180 in the patients were significantly lower than those in control individuals.The increase in both AUC 60→120 and AUC 0→180 values is statistically significant at the discontinuation of helmet therapy and at final follow-up.Receiver operating characteristic curve analysis indicated that AUC 60→120 is a more accurate classifier than AUC 0→180 .Conclusions: The proposed method objectively quantifies complex head shape and frontal retrusion in patients with metopic craniosynostosis and provides a quantitative measure for follow-up after surgical treatment.It avoids ionizing radiation exposure.