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Objective To discuss the three-dimensional conformal radiotherapy(3D-CRT) plan for pancreatic tumors.Methods The 3D-CRT plan of 30 cases of primary pancreatic cancer were designed according to the request of the doctors for PTV and the restricted receiving dose of the peripheral normal sensitive organs.The best plan was chosen referring the dose-volume histogram.Results By using ICRU dose reference point(the central point of target)as theunitary dose,95% dose line could be surrounded above 95% of the PTV.Conclusion The focus in different localization can be treated with different design in treating the pancreatic tumors.The reaction to radiotherapy is directly influenced by the volume and dosage of radiation to the normal hepatic tissues.
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The quality assurance method for the medical linear accelerator of large-scale radiotherapy equipment is introduced,whose periodic detection and adjustment are discussed.
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Objective To explore the methods and effects of body fractionated stereotactic radiotherapy(X-knife) in the treatment of lung metastases.Methods There were 50 cases with lung metastases were treated by fractionated stereotactic radiotherapy using CT orientation and WiMRT model body X-knife.The diameter of the metastases was 1.0cm-5.0cm.The linear accelerator was 6Mv X-ray.The dose per fraction was 5-12Gy,and the total prescribed dose was 30-52Gy at the margin of the PTV enveloped by 90% insodose curve.Results The metastases complete regression was found 21 fo-cus(18.3%)in CT image,partial regression in 70 focus(60.9%),and the overall effective rate was 79.1%.The effective rate for the focus with diameter less than 3cm was 88.5%,and 59.4% equal or more than 3cm,there was significan differ-ence(P
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Objective To investigate and carry out the function of the lead block validating instrument in the radiotherapy. Methods Based on clinical practice and the principle comparative steady STD and SAD of linear accelerator, the function of lead block validating instrument was developed in reason. Results The working quality and efficiency are greatly improved. Conclusion Not only the criterion extent of founded lead block and the proof of every kinds spume blocks in three-dimensional conformal radiotherapy and integer block radiotherapy and electron radiotherapy, but also the shadow tray centers and center reticle can be validated by the lead block validating instrument.
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Objective To apply lead block technology to the interdiction of X-ray destroy from linear accelerator to normal tissues and sensitive organs so as to treat large fields and irregular malignant lymphoma.Methods The steps were as follows:(1)immobilizing patients;(2)simulator photographing;(3)sketching targets;(4)tailoring lead block;(5)validating lead block.Results Problems of large fields and more targets were solved in radiotherapy for malignant lymphoma patients.Conclusion Based on clinical practice,new methods was found for realizing large irregular radiation fields.