Genauigkeit und lokale Kontrolle der kontinuierlichenextrakraniellen Radiochirurgie am Beispielintrapulmonaler Tumore

Table of Contents: Introduction: In literature it has been shown that a high local control for small intrapulmonal tumours is reached with a precise patient supposition and an exact application of the total dose. To lead a lethal dose into the tumour a time consuming and conformal treatment planning is necessary. Before treatment the patients experienced a second CT to get repositioned. After this CT-study a setup-vector has to be determined to calculate the difference between the two CT. In literature this value is about 6,0 – 6,8 mm. In this paper we tried to optimize the published methods to reach a faster but conformal stereotactic radiotherapy. Material and method: We tested a new method of an extracranial radiotherapy to treat patients with medical non-small cell lung cancer (NSCLC) or single metastases of the lung. They all had contraindications for or refused surgery. The patients were immobilised only once; for planning-CT, treatment planning and radiation with a vacuum body cast and an abdominal press, fixed on a steretactic body frame. Patients could be treated even of a bad lung function because no special breathing exercises are necessary and the total procedure needs only less than 2 hours so that a tolerable position was confirmed by all of them. Results Because of the patient’s continuous positioning we avoided a deviation of the body and so a second CT for repositioning. Virtual treatment-planning using a planning library, auto-segmentation and a fast planning system were the conditions for an optimized therapy for peripheral lung tumours. During the treatment we controlled – using a film option of the portal imaging system – the intrathoracical tumour movement by using DRRs, produced with the planning-CT. The result of this method was 59 a small setup-vector which showed a reduced patient’s movement during therapy so that a moving target could be radiated successfully. Conclusion Disease free survival and overall survival without worse secondary effects are comparable with the literature so that this new method is a fast and efficient therapy for patients with peripheral intrapulmonal and inoperable tumours.