Comparative Study with \({}^{89}\)Y-foil and \({}^{89}\)Y-pressed Targets for the Production of \({}^{89}\)Zr +
Footnote †: journal: Applied Physics Letters  
[PERSON]  
1 Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences,  
Universite de Sherbrooke, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada;  
[PERSON]S] (A.H.A.); [PERSON].T.)  
[PERSON]  
1 Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences,  
Universite de Sherbrooke, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada;  
[PERSON]S] (A.H.A.); [PERSON].T.)  
[PERSON]  
1 Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences,  
Universite de Sherbrooke, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada;  
[PERSON]S] (A.H.A.); [PERSON].T.)  
Footnote 1: email: {[PERSON]S], {[PERSON]S], {[PERSON].  
improve staging, provide an effective method to detect recurrence, and allow for the identification of patients who will be eligible for more personalized and adapted treatment to their specific cancer in order to improve their quality of life.  
Zirconium-89 can be produced by cyclotron using three different approaches involving either proton (H\({}^{+}\)), deuteron (\({}^{2}\)H), or alpha (\(\alpha\)) particle bombardment [7; 8; 9; 10; 11]. The production yield of \({}^{89}\)Zr obtained by (p,n) reaction on \({}^{89}\)Y is comparable to the one of (p,pxn) reaction on \({}^{\mathrm{nat}}\)Zr and notably higher than (\(\alpha\),n) reaction on \({}^{\mathrm{nat}}\)Sr and (d,2n) reaction on \({}^{89}\)Y, along with higher radionuclide purity [9; 11; 12].  
\({}^{89}\)Y is available under various forms, including foils, wires, and powder with purity greater than 99.6%. The target material is mononuclidic and the use of enriched isotopes for irradiation is unnecessary. \({}^{89}\)Y foil is commonly chosen for its availability and easy handling [13; 14]. High effective molar activity (EMA) of the isolated \({}^{89}\)Zr fractions has been measured while using \({}^{89}\)Y-foil [5], Zirconium-89 can also be produced using a liquid target with yttrium nitrate salts via the \({}^{89}\)Y(p,n)\({}^{89}\)Zr reaction. Production of radiometals in solution is challenging due to in-target salt precipitation and unstable target pressures that are caused by gas evolution during irradiation [15]. Moreover, the production yield of \({}^{89}\)Zr in solution target is still well below the solid target production yield [5; 16]. [PERSON] et al. showed that the production of no-carrier-added \({}^{89}\)Zr from deuteron irradiation of natural \({}^{89}\)Y-pressed targets was obtained in high yield, but within the energy window studied, \({}^{88}\)Zr was also produced [8]. Other methods, including yttrium-sputtering deposition [17] and spot-welding [18], have been studied for the preparation of \({}^{89}\)Zr, but pressing would be advantageous in view of cost and productivity.  
In the current study, we investigated for the first time the use of an \({}^{89}\)Y pressed powder target to produce \({}^{89}\)Zr via proton irradiation. A comparative study with existing \({}^{89}\)Y-foil target is presented in order to outline the full potential of this novel pressed target. We studied the dimension and thickness of the solid targets under different irradiation conditions and we optimized the design of the target supports. We also developed an automated extraction and purification process while using a cassette-based module allowing for the fractionation of \({}^{89}\)Zr. Results are presented and discussed with the objective of maximizing the thickness of the solid targets and obtaining high-yield, high-purity, and high-EMA as \({}^{89}\)Zr-oxalate.