Peripheral doses in patients undergoing Cyberknife treatment for intracranial lesions. A single centre experience

Radiation Oncology

George Panayiotakis²  Dimitrios Kardamakis³  Nikolaos Salvaras¹  Argyrios Tzouras¹  Harry Delis²  Christos Antypas¹  Vassiliki Vlachopoulou² 

[1] CyberKnife Center, Iatropolis, Athens, Attica, Greece;Department of Medical Physics, School of Medicine, University of Patras, Achaia, Greece;Department of Radiology, School of Medicine, University Hospital of Patras, Achaia, Greece

关键词: stereotactic/radiosurgery radiotherapy;    peripheral dose;    MOSFET;    intracranial lesions;    Cyberknife;   

Others  :  1223816
DOI  :  10.1186/1748-717X-6-157

 received in 2011-09-04, accepted in 2011-11-14,  发布年份 2011

【 摘 要 】

Background

Stereotactic radiosurgery/radiotherapy procedures are known to deliver a very high dose per fraction, and thus, the corresponding peripheral dose could be a limiting factor for the long term surviving patients. The aim of this clinical study was to measure the peripheral dose delivered to patients undergoing intracranial Cyberknife treatment, using the MOSFET dosimeters. The influence of the supplemental shielding, the number of monitor units and the collimator size to the peripheral dose were investigated.

Methods

MOSFET dosimeters were placed in preselected anatomical regions of the patient undergoing Cyberknife treatment, namely the thyroid gland, the nipple, the umbilicus and the pubic symphysis.

Results

The mean peripheral doses before the supplemental shielding was added to the Cyberknife unit were 51.79 cGy, 13.31 cGy and 10.07 cGy while after the shielding upgrade they were 38.40 cGy, 10.94 cGy, and 8.69 cGy, in the thyroid gland, the umbilicus and the pubic symphysis, respectively. The increase of the collimator size corresponds to an increase of the PD and becomes less significant at larger distances, indicating that at these distances the PD is predominate due to the head leakage and collimator scatter.

Conclusion

Weighting the effect of the number of monitor units and the collimator size can be effectively used during the optimization procedure in order to choose the most suitable treatment plan that will deliver the maximum dose to the tumor, while being compatible with the dose constraints for the surrounding organs at risk. Attention is required in defining the thyroid gland as a structure of avoidance in the treatment plan especially in patients with benign diseases.

【 授权许可】

   
2011 Vlachopoulou et al; licensee BioMed Central Ltd.

【 图 表 】

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