Volumetric modulation arc radiotherapy with flattening filter-free beams compared with conventional beams for nasopharyngeal carcinoma: a feasibility study / 癌症

There is increasing interest in the clinical use of flattening filter-free (FFF) beams. In this study, we aimed to investigate the dosimetric characteristics of volumetric modulated arc radiotherapy (VMAT) with FFF beams for nasopharyngeal carcinoma (NPC). Ten NPC patients were randomly selected to undergo a RapidArc plan with either FFF beams (RA-FFF) or conventional beams (RA-C). The doses to the planning target volumes (PTVs), organs at risk (OARs), and normal tissues were compared. The technical delivery parameters for RapidArc plans were also assessed to compare the characteristics of FFF and conventional beams. Both techniques delivered adequate doses to PTVs. For PTVs, RA-C delivered lower maximum and mean doses and improved conformity and homogeneity compared with RA-FFF. Both techniques provided similar maximum doses to the optic nerves and lenses. For the brain stem, spinal cord, larynx, parotid glands, oral cavity, and skin, RA-FFF showed significant dose increases compared to RA-C. The dose to normal tissue was lower in RA-FFF. The monitor units (MUs) were (536 ± 46) MU for RA-FFF and (501 ±25) MU for RA-C. The treatment duration did not significantly differ between plans. Although both treatment plans could meet clinical needs, RA-C is dosimetrically superior to RA-FFF for NPC radiotherapy.

Review of absolute quantification of brain metabolites by using multi-voxel 1H-MRS / 国际生物医学工程杂志

The technology of Magnetic Resonance Spectroscopy(MRS) is a newly-developed mean for analyzing some specific nucleus and their compounds making use of the principles of magnetic resonance and the effects of chemical shift. Currently, among MRS applications, proton magnetic resonance spectroscopy (1HMRS) is the most widely applied one developed from single voxel to three-dimensional multi-voxel scanning technique. It provides a lot of important information for clinical studies. This article mainly reviews the methods for absolute quantification measurement of brain metabolites using multi-voxel MRS.

Design of Large-scale Clusters PACS / 医疗卫生装备

Obiective To design large-scale clusters PACS. Methods The concept of large-scale clusters PACS was proposed firsdy, which is combined with the corresponding instances analysis on the systemic characteristics pros and cons. The important function of EPR with images in the large-scale clusters PACS and basic design were discussed. The distributed architecture design of medical imaging in large-scale clusters PACS was put forward, and then focuses on the composition and requirements of clinical part, required post-processing application of clinical specialist part and IT support part. Results The domestic application of clinical information system can bring leapfrog development by large-scale clusters PACS. Conclusion The large-scale clusters PACS will have good future prospection of popularization in our country.

Development of Performance Evaluation Testbed for PACS / 医疗卫生装备

Objective To develop a performance evaluation testbed for PACS.Methods The basic architecture and primary functions of PACS was simulated to test its robustness and effectiveness.Results The testbed could be used in not only the clinical performance evaluation of PACS but also the study,training and teaching of PACS.Conclusion The practicability and reliability of the testbed have been proved through its tryout.