**Part 3**

**Basic Science** 

154 Gamma Knife Radiosurgery

Yamamoto, Y. , R. J. Coffey, D. A. Nichols, and E. G. Shaw. 1995. Interim report on the

Young, W. L. , A. Kader, J. Pile-Spellman, E. Ornstein, and B. M. Stein. 1994. Arteriovenous

Zabel, A. , S. Milker-Zabel, P. Huber, D. Schulz-Ertner, W. Schlegel, and J. Debus. 2005.

Zabel-du Bois, A. , S. Milker-Zabel, P. Huber, W. Schlegel, and J. Debus. 2007. Risk of

Zarem, H. A. , and R. Soderberg. 1982. Tissue reaction to ischemia in the rabbit ear chamber:

Zipfel, G. J. , P. Bradshaw, F. J. Bova, and W. A. Friedman. 2004. Do the morphological

(3):361-9.

discussion 395-6.

*Oncol* 77 (1):105-10.

*Surg* 70 (6):667-76.

*Neurosurg* 101 (3):393-401.

*Oncol Biol Phys* 68 (4):999-1003.

radiosurgical treatment of cerebral arteriovenous malformations. The influence of size, dose, time, and technical factors on obliteration rate. *J Neurosurg* 83 (5):832-7. Yen, C. P. , P. Varady, J. Sheehan, M. Steiner, and L. Steiner. 2007. Subtotal obliteration of

cerebral arteriovenous malformations after gamma knife surgery. *J Neurosurg* 106

malformation draining vein physiology and determinants of transnidal pressure gradients. The Columbia University AVM Study Project. *Neurosurgery* 35 (3):389-95;

Treatment outcome after linac-based radiosurgery in cerebral arteriovenous malformations: retrospective analysis of factors affecting obliteration. *Radiother* 

Hemorrhage and Obliteration Rates of LINAC-Based Radiosurgery for Cerebral Arteriovenous Malformations Treated After Prior Partial Embolization. *Int J Radiat* 

effects of prednisolone on inflammation and microvascular flow. *Plast Reconstr* 

characteristics of arteriovenous malformations affect the results of radiosurgery? *J* 

**9** 

*Canada* 

**Applications of Gamma Knife Radiosurgery for** 

The Gamma Knife (GK) was not originally designed for experimentations in small animals. In fact, there are no compatible custom accessories or stereotactic frames on the market for the spatial positioning of small animals in the GK. In addition, the GK is intensively used for patient treatments, and consequently the access for research with small animals is limited. On the other hand, devices specially designed for the irradiation of small animals are available on the market. For examples, small animal irradiators can be purchasable from Best Theratronics (Theratronics, 2011), Rad Source Technologies (Rad Source Technologies, 2011), Precision X-Ray Inc. (Precision X-Ray, 2011) and Xstrahl-Gulmay Medical Inc. (Xstrahl, 2011). Compared to the GK, these small animal irradiators have the following advantages: lower cost, smaller size, some are shielded and thus don't require a special shielded room, some can be combined with an imaging device that allows to image the animal and immediately irradiate the region of interest and, if needed, repeat imaging. Then, since irradiators designed for small animal already exist, why use a GK for animal experimentations? The answer should include technical as well as conceptual aspects. The most important benefit of using the GK for small animals is related to the difference between conventional external radiotherapy and GK radiosurgery (GKRS). Radiation deposition with a GK is produced by multiple concentric beams that allow high dose deposition in a very small volume. These converging beams of ionizing radiation in a precise volume allow a rapid fall-off of dose near the edges which limit adverse effects on

This chapter is devoted to a review of some characteristics of "homemade" stereotactic frames allowing small animal fixation in the Gamma Knife, and explores small animal

**2. In-house designed stereotactic frame for use with the Gamma Knife for** 

Even if GK is reported to be used for irradiation of large animals like cat and baboon (Kondziolka et al., 2002; Kondziolka et al., 2000; Lunsford et al., 1990; Nilsson et al., 1978), this chapter is focused on small animals (mouse, rat) because of their frequent uses in

researches done with a Gamma Knife published in the literature.

**1. Introduction** 

the surrounding adjacent tissue.

**small animals** 

**Experimental Investigations in** 

Gabriel Charest, Benoit Paquette and David Mathieu

*Department of Nuclear Medicine and Radiobiology, Sherbrooke University* 

**Small Animal Models** 
