Any center planning to install a Gamma Knife radiosurgery unit has to provide for an efficient shielding of the treatment room, to protect the patient, the staff and the public, against undesired radiation. The shielding barrier design is controlled by national and international recommendations; the reference documents for gamma ray radiotherapy facilities are the National Council on Radiation Protection and Measurements (NCRP) reports 49 and 151. However, some facts highlighted in this thesis point out that NCRP methods are ill-adapted to the Gamma Knife. Spectroscopic measurements were performed around the Gamma Knife with a Germanium detector. They revealed that the radiation field contains few high energy photons, is highly anisotropic, and that the leakage level is much lower than the NCRP estimation. These observations led to the development of a new approach to determine the necessary shielding, based on the actual and directly measurable radiation field around the unit. This method would reduce the shielding oversizing induced by the unsuitability of the NCRP recommendations for the Gamma Knife.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-202108 |
| Date | January 2017 |
| Creators | Hubert, Alexis |
| Publisher | KTH, Skolan för teknik och hälsa (STH), Elekta AB |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-STH ; 2017:5 |
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