ABSTRACT
OBJECTIVE: To evaluate the obliteration rate and clinical outcome following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) in pediatric patients (age ≤18 years). METHODS: Factors associated with the obliteration rate and neurologic complications were studied retrospectively in pediatric patients who underwent LINAC-based SRS for AVM between June 1995 and May 2014. RESULTS: The study cohort comprised 36 males and 33 females, with a median age at the time of SRS of 14 years (range, 7-18 years). The mean AVM volume was 8.5 ± 8.7 cc (range, 0.6-41.8 cc). The median marginal dose of radiation delivered was 15 Gy (range, 9-20 Gy). Magnetic resonance imaging (MRI) demonstrated complete obliteration of the AVM in 44 of the 69 patients (63.8%), at a mean follow up of 27.5 months (range, 12-90 months). On subgroup analysis, 41 of the 53 AVMs of ≤14 cc in volume (77.3%) were obliterated. AVMs with a modified AVM radiosurgery score <1 had significantly shorter obliteration times from the time of SRS (P = .006). On multivariate analysis, the mean marginal dose of radiation delivered to the AVM was the sole significant predictor of obliteration (odds ratio, 1.6; 95% confidence interval, 1 to 2.4). CONCLUSIONS: A modest median marginal dose of 15 Gy (16 Gy in the obliterated AVM group vs. 12 Gy in the nonobliterated group) resulted in an obliteration rate of 66.7% after LINAC-based SRS for intracranial AVM, with low rate.
Subject(s)
Intracranial Arteriovenous Malformations/radiotherapy , Radiosurgery/methods , Radiotherapy Dosage , Adolescent , Angiography, Digital Subtraction , Cerebral Angiography , Child , Cohort Studies , Female , Humans , Intracranial Arteriovenous Malformations/diagnostic imaging , Magnetic Resonance Imaging , Male , Particle Accelerators , Retrospective Studies , Treatment OutcomeABSTRACT
BACKGROUND: Purpose of the present study was to examine the response of cervical cancer cell line (HeLa cell line) to low dose radiation using clonogenic assay and mathematical modeling of the low dose response by Joiner's induced repair model. MATERIALS AND METHODS: Survival of HeLa cells following exposure to single and fractionated low doses of γ (gamma)-ray, 6 MV, and 15 MV photon was measured by clonogenic assay. RESULTS: HeLa cell line demonstrated marked low dose response consisting of an area of HRS and IRR in the dose region of <1 Gy. The two gradients of the low dose region (αs and αr) were distinctly different with a transition dose (Dc) of 0.28-0.40 cGy. CONCLUSION: HeLa cell line demonstrates marked HRS and IRR with distinct transition dose. This may form the biological basis of the clinical study to investigate the chemo potentiating effect of low dose radiation in cervical cancer.
