Photos:	Ruthenium 106 eye plaques	Different Brands of Eye Plaques[6]
		Example of seeds in plaque which can be Ru-106, I-125 or Pd-103 [6]

Relevant Historical Data:	Ruthenium was discovered and isolated by Russian scientist Karl Klaus in 1844 in Kazan University, Kazan. Klaus showed that ruthenium oxide contained a new metal and obtained 6 grams of ruthenium from the part of crude platinum that is insoluble in aqua regia. The name derives from Ruthenia, the Latin word for Rus', a historical area which includes present-day western Russia, Ukraine, Belarus, and parts of Slovakia and Poland. Karl Klaus named the element in honor of his birthland. (2) The discovery of rhodium has been attributed to William Hyde Wollaston who discovered it in England in 1803. He successfully isolated it from a crude ore shortly after having discovered palladium. The name rhodium is derived from the Russian word “rhodon” which means rose. [14]
Chemical/Radioactive Composition:	Chemical Symbol: Ru Atomic number (Z, # of protons)=44 Mass number (A, # of protons + neutrons) = 106 A member of the Platinum family, Uranium-235 decays down to Ruthenium-106, a high energy beta emitter. Ruthenium-106 decays to daughter Rhodium- 106, which decays to Palladium 100.[3] Ruthenium fission only yields .38%. Ru-106 has a maximum energy of 3.5 Mev.[4]
Energy Characteristics:	Beta particle energy 3.5 MeV maximum for Ru-106.[9] The mean and maximum energy of 106Rh beta radiation is 1.412 MeV and 3.54 MeV, respectively. The mean energy of gamma radiation is 0.5988 MeV, where the greatest yields belong to 0.512, 0.622, and 1.05 MeV transitions. [8] The maximum range of 106Ru/106Rh electrons in water is roughly 16 mm thus the rest of the dose in greater distances is due to 106Rh photons and bremsstrahlung.bremsstrahlung.[8]
Exposure Rate Constant:	A fission product with a yield of 0.3912%. The activity used for eye plaques ranges from 0.3-1.4 mCi with a surface dose rate up to 70cGy/hr. Exposure rate constant: Rh-106 - 0.138158. [15] Because Ru-106 is a beta emitter, it does not have an exposure rate constant.
Half-life Properties:	Ru -106 half-life 373.6 days Rh-106 half-life 29.8 seconds Both are Beta emitters.[1]
Forms available for use:	Usually embedded in a thin foil of metal such as silver and used for eye applicators which are used for treating choroidal/ocular melanoma.
HVL in lead:	HVL in water or tissue is 2.5mm.[4] Could not find HVL in lead, however it will be minimal considering the HVL depth in water.
Measurement/Calibrations/QA:	Ruthenium-106 emits beta particles with a maximum energy of 39 keV, and can be counted by itself only with a detector sensitive to very low-energy beta particles. Its rhodium-106 daughter, however, emits energetic beta particles and gamma rays that can be measured with most beta or gamma detectors. [16] QA for any brachytherapy includes time, distance and shielding. Keep as much distance as possible from the source. Limit the time spent exposed to the source. Varify the use of proper shielding of the source.[10] Temporary implant needs a decay factor calculation (which is e(-.693/373.6 days) = .998/day or a decay of approximately .2% per day). This is used to calculate the dose from the dose at shipment of the source to the time of implantation. A measurement is taken of the source upon delivery by placing the source in a well counter to varify the dose at shippment.[11] After removal of the plaque with the Ru-106 seeds, standare brachy procedures are used for release of the patient. The room is surveyed with a GM counter to reassure that no radioactive contamination is left behind.[10]
Used in formula/calculation:	The Monte Carlo technique provides a powerful tool for calculation of the dose and dose distributions which helps to predict and determine the doses from different shapes of various types of eye applicators more accurately.[8] The Monte Carlo code MCNPX has been used to calculate dose distributions from a COB-type 106Ru/106Rh ophthalmic applicator manufactured by Eckert & Ziegler BEBIG GmbH.[8] Several dose distributions are calculated: a distribution on a spherical surface 1 mm above the surface and three planar distributions on planes XY (horizontal plane), XZ (vertical plane passing the cut-out), and a plane just in front of the applicator parallel to the plane YZ.[8] All values were normalized to the value on the central axis at the distance of 1 mm above the surface.[8] Mean life = 1.44 (T1/2) =1.44 x 373.6 days =537.98 days Decay constant = 0.693/373.6 days =.0018 per day
Uses in Radiation Oncology:	Ru-106 is used in eye plaques and attached to the retina of the eye to deliver a dose of brachytherapy radiation. This procedure is done to treat opthalmic melanoma.[4] A typical total dose of 85 Gy is delivered to the tumor. Plaques are designed custom fitted to the shape of the treatment area in the range of 12 to 22 mm. Calculations are done using a Plaque Simulator treatment planning software to deliver the dose to the apex of the tumor.[7] Dose rate during plaque treatment at the center applicator surface can be as high as 100 cGy/second. The dose rate may vary greatly across the applicator. The dose rate from a beta applicator decreases to about 5% of the surface dose rate at a depth of 4mm, the depth of the lens below the cornea.[9] The plaques are usually made of attenuation material such as a gold alloy, and a means for attaching seed inside the plaque. The gold shell limits the dose to uninvolved strutures of the eye, by providing some limited collimation. The plaque also protects other organs, as well as persons in the vicinity of the patient. The plaque is ordinarily left in place for up to a week while the treatment id delivered.[9]
Treatment Planning:	Beta-ray emitting Ru-106/Rh-106 ophthalmic applicators have been used for close to 4 decades in the treatment of ophthalmic melanoma. The form factor of these applicators is a spherically concave silver bowl with an inner radius of curvature between 12 and 14 mm, and a total shell thickness of 1 mm. The radioactive nuclide is deposited in a layer 0.1 mm below the concave surface of the applicator. Calculation of dose distributions for clinical treatment planning purposes is complicated by the concave nature of the distributed source, the asymmetric shape of the active region of some applicators, imperfections in the manufacturing process which can result in an inhomogeneous distribution of activity across the active surface, and absorption and scatter in the 0.1 mm layer of silver which seals and protects the radioactive layer. A semi-empirical method of calculating dose distributions for these applicators is described which is fundamentally compatible with treatment planning systems that use the AAPM TG43 Brachytherapy formalism. [12]
One other interesting fact:	Fountain pen nibs are frequently tipped with alloys containing ruthenium. From 1944 onward, the famous Parker 51 fountain pen was fitted with the "RU" nib, a 14K gold nib tipped with 96.2% ruthenium and 3.8% iridium. [13] Rhodium is used for jewelry, for decoration, and as a catalyst. Forty four isotopes and isomers are now known. Rhodium metal (powder) costs about $300/g (99.9% pure). [17]

Links:
http://www.iop.org/EJ/article/1742-6596/102/1/012021/jpconf8_102_012021.pdf?request-id=a5d11cdc-b78a-482b-8b6b-6648809b0f64


References:
1. The Berkley Laboratory Isotopes Projects. Available at: http://ie.lbl.gov/education/isotopes.htm, Accessed March 17, 2009.
2. Wikipedia. Ruthenium 106. Available at:http://en.wikipedia.org/wiki/Ruthenium. Accessed March 19, 2009
3. Platinum Group Metals. Available at: http://books.google.com/books?id=sJsrAAAAYAAJ&pg=PA42&dq=rhodium-106&ei=T-HQSdeBM5O-M7HmudAO. Accessed March 30, 2009.
4. T. Wiegel, N. Bornfeld, W. Hinkelbein, M.H. Forester, Radiotherapy of Ocular Disease, 1997, volume 30, Karger publishing.
5. Absolute Astronomy. Ruthenium-106. Available at: http://www.absoluteastronomy.com/topics/Ruthenium-106. Accessed on April 1, 2009.
6. Eye Physics web site. Available at: www.eyephysics.com. Accessed April 2, 2009.http://bjr.birjournals.org/cgi/content/abstract/76813976v1
7. The British Journal of Radiology. Available at: http://bjr.birjournals.org/cgi/content/abstract/76813976v1, Accessed April 2, 2009.
8. Third McGill International Workshop. Journal of Physics: Conference Series 102 (2008) 012021. Monte Carlo calculation of dose to water of a 106Ru COB-type ophthalmic plaque. Available at: http://www.iop.org/EJ/article/1742-6596/102/1/012021/jpconf8_102_012021.pdf?request-id=57710980-ec10-47cb-9b24-899bcd1d0308. Accessed April 3, 2009.
9. Hendee, William R., Ibbott, Geoffrey S., Radiation Therapy Physics, second edition, Mosby publishing,1996, p. 369, 409.
10. University of Wisconsin- LaCross, D2L DOS 400, Brachytherapy for Medical Dosimetrists, accessed April 6, 2009.
11. Don Thompson MMP, Physicist, United Radiation Oncology, Lexington, KY, April 6, 2009.
12. Chao, KS., Perez, Carlos A., Brady, Luther W. Radiation Oncology Management Decisions, 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2002. pp. 511-518
13. Ruthenium 106. Available at:http://en.wikipedia.org/wiki/Ruthenium. Accessed March 15, 2009
14. Azom. com. Rhodium- Discovery, Occurrence, Production, Poperties, and Application. Available at: http://www.azom.com/Details.asp?ArticleID=3483. Accessed on April 7, 2009.
15. Integrated Environmental Management, Inc. Gamma Ray Dose Constants. Available at: http://www.iem-inc.com/toolgam.html. Accessed on April 7, 2009.
16. Kahn B, Choppin GR, Taylor JG. User's Guide for Radioactivity Standards. Tennessee: United States Atomic Energy Commission; 1967.
17. Mr. Everett's Web Page. Rhodium. Available at:http://www.mrteverett.com/Chemistry/pdictable/q_elements.asp?Symbol=Rh. Accessed on April 7, 2009.

Color Codes:
Candice - Orange
Sherri - Green
Robin B.- Blue
Allan -Red