Positioning errors of CT common rail technique in intensity-modulated radiotherapy for nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the value of CT common rail technique for application in intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC).</p><p><b>METHODS</b>Twenty-seven NPC patients underwent Somatom CT scans using the Siemens CTVision system prior to the commencement of the radiotherapy sessions. The acquired CT images were registered with the planning CT images using the matching function of the system to obtain the linear set-up errors of 3 directions, namely X (left to right), Y (superior to inferior), and Z (anterior to posterior). The errors were then corrected online on the moving couch.</p><p><b>RESULTS</b>The 27 NPC patients underwent a total of 110 CT scans and the displacement deviations of the X, Y and Z directions were -0.16∓1.68 mm, 0.25∓1.66 mm, and 0.33∓1.09 mm, respectively.</p><p><b>CONCLUSION</b>CT common rail technique can accurately and rapidly measure the space error between the posture and the target area to improve the set-up precision of intensity-modulated radiotherapy for NPC.</p>

Clinical efficacy of neoadjuvant therapy in treatment of middle and low advanced rectal cancer anuspreserving surgery / 肿瘤研究与临床

Objective To study the clinical value of neoadjuvant radiotherapy (NRT),neoadjuvant chemoradiotherapy (NCRT) or surgery alone (S) in treatment of middle and low rectal cancer.Methods 139 cases were divided into 3 groups:47 cases were given NRT (50 Gy/25 f/5 w) as group NRT,46 cases were given NCRT (Capox+ radiotherapy) as group NCRT,and the remaining 46 cases were treated with surgery alone as group S.Patients in 3 groups were followed-up for 3 years for the observation of the rates of anuspreserving and 3-year survival rates.Results Compared with the patients in group S,the rates of anuspreserving in group NRT and NCRT were significant improvement [74.47 ％ (35/47) and 73.91％ (34/46) vs 54.35 ％ (25/46)],(x2 =4.111,3.827; P=0.043,0.050).The 1,2,3-year survival rates of the 3 groups had no significantly different (P ＞0.05).However,the 1-year survival rates might be lower in group NRT and group NCRT than that in group S [87.23 ％ (41/47) and 88.89 ％ (40/45) vs 97.83 ％ (45/46)] (x2 =4.611,P =0.100).Conclusion NRT and NCRT can improve the rate of anus-preserving,but might not improve the 1,2,3-year survival rate,instead,the death rate may increase in the first year.

Development of a new head and neck location frame for PET and CT cross-modality medical image fusion in radiotherapy / 生物医学工程学杂志

A new head and neck location frame for positron emission tomography (PET) and computed tomography (CT) cross-modality medical image fusion in radiotherapy was developed. The solid mark bars of N form in the old designed CT location frame were replaced by closed hollow pipes which could be filled with different developer solutions before CT or PET scan, respectively. Nine points of external marker used for registration and fusion were obtained in CT images and PET images, respectively. The locations of the two sets of nine points showed the method of registration to be effective and accurate in achieving the PET and CT image fusion. This method, based on its characteristics of simple structure and easy-to-use, can be of wide application in clinical setting.

Research and experiment of compensator made by split method for static intensity-modulated radiation therapy / 医疗卫生装备

Objective To help the hospitals at all levels in China to realize IMRT by adding the accurate location equipments and TPS based on the existing general radiation therapy from research of the new method for static Intensity-modulated radiation therapy. Method Based on the controlled technique of CRT, a new split method for fabricating the three-dimensional physics compensator to achieve the IMRT was developed. Results The Experiment manifested that the compensator fabricated by the way could make the high dosage shape of target in accordance with the form of tumor and could adjust the distribution of the dosage according to remedy requirement. Conclusion The method is simple and feasible, and has brilliant clinical prospective and popularized significance.

Research on control circuit of a new CT simulation laser positioning system / 医疗卫生装备

CT laser simulation positioning system is a necessary auxiliary device for radiotherapy. Its main purpose is to position patients by simulating different kinds of treatment machine. In order to demarcate the mark of the iso-center, it is common to use the laser positioning device to indicate the iso-center. The kernel technology of the laser positioning system is the controlling of the step progress motor by using the MCS, which is to control the movement of step progress motor using the wheel of the motor. This design uses MCS-51 to control step progress motor by the way of exporting the rectangle wave form through I/O port of 8255 chip. The system configuration is simple, the operation is convenient and the positioning is precise.