ABSTRACT
Personal dosimeters based on optically stimulated luminescence (OSL) have been widely used for many years to monitor the occupational exposure of radiation workers. More recently, their use has been investigated and adopted for in vivo dosimetry of patients undergoing medical procedures, such as radiation therapy or diagnostic imaging. This chapter focuses specifically on the characteristics and the clinical uses of small OSL dosimeters used as passive point detectors for in vivo patient dosimetry. Currently, there is only one commercial source of these detectors. The nanoDot https://www.w3.org/1998/Math/MathML"> Â r y https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2697.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> , produced by Landauer Inc. (Glenwood, Illinois), utilizes a https://www.w3.org/1998/Math/MathML"> 5 Â m m https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2698.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> -diameter, https://www.w3.org/1998/Math/MathML"> 0.2 Â m m https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2699.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> -thick disk containing https://www.w3.org/1998/Math/MathML"> A l 2 O 3 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2700.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> : C. As seen in Figure 18.1, the disk is mounted inside a light-tight plastic case, measuring approximately https://www.w3.org/1998/Math/MathML"> 10 × 10 × 2 Â m m https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2701.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> in dimensions. Landauer also produced a larger https://www.w3.org/1998/Math/MathML"> O S L https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2702.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> Dot, which contained a https://www.w3.org/1998/Math/MathML"> 7 Â m m https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2703.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> -diameter https://www.w3.org/1998/Math/MathML"> A l 2 O 3 : C https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2704.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> disk inside a https://www.w3.org/1998/Math/MathML"> 24 × 12 × 2 Â m m https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315372655/b2ce6ef4-5376-4be5-9af3-87940a039f56/content/eq2705.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> plastic case. The physics of OSL dosimetry has been described in detail in Chapter 17. In simple terms, radiation can excite electrons out of the conduction band, creating free electrons and holes. Some of these electrons and holes become stably trapped in isolated energy states created by the lattice defects in the crystal. Stimulation of the material with a light source will release trapped electrons,
