Regularized inhomogeneity correction method for phased array image in magnetic resonance imaging / 生物医学工程学杂志

Phased array coils (multiple receiver coil systems) have been extensively used for acquisition of MR images owing to their ability of increasing SNR, extending field-of-view (FOV), and reducing acquisition time. But the SOS algorithm,which is main method for phased array image reconstruction,will cause inhomogeneity in reconstructed image. A regularized least square method for phased array image combination is proposed in this paper. In the method, an additional reference scan is performed in advance. By using the reference scan, coil sensitivity map can be acquired, and image reconstructed from reference scan can be used as reference data in the regulation term. Experiments showed that the image uniformity was greatly improved by this method with scanning phantom and volunteer.

Late course accelerated hyperfractionation radiotherapy and concurrent chemothe rapy on esophageal carcinoma / 中华放射肿瘤学杂志

Objective To compare the treatment effects and toxicity of late co urse accelerated hyperfractionation radiotherapy (LCAFR), LCAFR plus concurren t chemotherapy (LCAFR+C) and conventional fractionation radiotherapy(CFR) on esop hageal cancer. Methods 150 patients with squamous carcinoma of thoracic esophag us were divided randomly into three groups: 1.CFR group, patients were irradiate d 2.0?Gy/f, 5 times a week, to a total does of 60?Gy. 2. LCAFR group, patients wer e first irradiated with CFR to 30?Gy, then followed by 1.5?Gy/f bid, at more t han 6 hours' interval, to the total dose of 60?Gy. 3.LCAFR+C group: The radiotherap y technique was the same as the LCAFR group, but weekly 20 mg DDP and 500 mg 5-Fu wer e added simultaneously for 5 weeks. Results All three groups completed their tre atment course. Of CFR, LCAFR and LCAFR+C groups, the 1-,2-,3- and 4-year sur viva l rates were 54%, 30%, 18%, 18%; 76%, 56%, 44%, 42% and 82%, 62%, 50%, 44%. The 1-,2-,3- and 4-year local control rates were 40%, 32%, 26%, 24%; 72%, 60%, 5 6%, 54% and 78%, 66%, 60%, 56%, with obvious better results in the latter two groups (P0.05). The acute toxic effect was severer in the LCAFR+C g roup than in the other two, with the difference significant between the LCAFR+C and CFR group, bu t not between the LCAFR and CFR group. The tolerance of the patients to LCAFR wa s better than that of LCAFR+C group. There were no significant differences in la te complications and causes of death between the three groups. The main cause of death was local recurrence and uncontrolled primary disease, which were signifi cantly lower in the LCAFR and LCAFR+C groups than in the CFR group. Conclusions Both late course accelerated hyperfractionation radiotherapy and late course acc elera ted hyperfractionation radiotherapy plus chemotherapy can significantly improve the local control and survival of esophageal cancer, but the latter has increase d toxicity. Concurrent small dose chemotherapy can not lowered the remote metas tatic rate.