ABSTRACT
Objective Whole brain radiotherapy ( WBRT) remains the primary treatment for patients with multiple brain metastases ( BM). Hippocampal avoidance WBRT ( HA-WBRT) offers the feasibility of less cognitive function impairment than conventional WBRT.WBRT yields better control rate of intracranial distant progression than stereotatic body radiotherapy (SBRT).This study aims to understand the distribution characteristics of BM within the cranial structures by analyzing imaging features and define the safe margin during HA-WBRT. Methods Clinical data of patients diagnosed with BM by enhanced MRI in Ruijin Hospital from July 2011 to July 2016 were retrospectively analyzed. The distance between the intracranial lesion closest to the hippocampus and the hippocampus was measured. Results A total of 146 patients (90 male and 56 female) with 630 BM lesions were reviewed. Sixty-four patients were diagnosed with non-small-cell lung cancer complicated with BM during the initial admission. In the other 82 patients, the average time from the initial diagnosis to the diagnosis of BM was (14.5±14. 3) months. In total,486 (77. 1％) BM lesions were situated beyond the tentorium. The average diameter of the largest intracranial lesion was (12.5± 10. 3) mm (95％CI:10. 8-14. 2). All 630 BM lesions were distributed as follows:138 (21. 9％) in the cerebellum, 182 ( 28. 9％) in the frontal lobe, 114 ( 18. 1％) in the temporal lobe, 78 (12. 4％) in the parietal lobe,87(12. 7％) in the occipital lobe,28(4. 4％) in the thalamus and 10(1. 6％) in the brainstem. The frequency of hippocampal involvement was 3. 4％(5 mm),4. 8％(10 mm) and 8. 2％(20 mm). The univariate and multivariate logistic analyses indicated that with the risk of hippocampal involvement in patients aged> 60 years was significantly increased (OR= 11. 576 P= 0. 042). Conclusions The probability of brain metastasis within 10 mm around the hippocampus is low. HA-WBRT can control the intracranial lesions and reduce cognitive impairment,which is a safe and feasible treatment method.
ABSTRACT
Objective To assess and compare the advantages and disadvantages of five fields of three dimensional conformal radiation therapy(3DCRT),three fields of 3DCRT and the simulator-guided radiation therapy for patients with esophageal carcinoma.Methods Twenty patients with esophageal carcinoma were treated by three dimensional conformal radiation therapy,at the same TPS,three Dimensional conformal radiation therapy target and normal tissue of three radiotherapies were simulated.The treatment planning was five days per week with 1.8～2.0 Gy per fraction。 5 fractions per week,5OGy per 5～6 weeks. Results Compared with simulator-guided radiation therapy,3DCRT planning has better dose distribution and protection of normal tissue. Conclusion Esophageal cancer conformal radiotherapy can reduce the radiation injury of the normal tissue and complications,and improve treatment of conformal radiotherapy and the target dose distribution.