## 1 Introduction  
Lead is the most widely used material for radiation shielding in medical institutions [1]. Because of its excellent processability, it is sometimes used as a plate or mixed with a polymer material to produce a sheet or film [2]. However, lead is classified as a heavy metal; thus, the environmental concerns owing to its toxicity have led to a reduction in its use [3]. Therefore, an eco-friendly material with excellent shielding performance, processability, and compatibility with other materials is a topic of research interest [4, 5]. Tungsten, a substitute for lead, is one of the most widely used radiation-shielding materials in medical institutions [6]. It has an atomic number of 74, an atomic weight of 183.84 g/mol, and a density of 19.25 g/cm\({}^{3}\), with a shielding performance comparable to that of lead [7]. Tungsten is mainly used as tungsten oxide or tungsten carbide, and it is difficult to manufacture a tungsten shield in a desired shape by directly processing it due to its high melting point of 3400 \({}^{\circ}\)C [8, 9]. However, as it shows excellent affinity with other composite materials, tungsten can be used as a shield of various types when mixed suitably [10]. Typically, X-ray shields used in medical institutions are made of thin plates by mixing lead, tin, and copper [11]. However, challenges with disposal and the weight of the product restrict its application [12, 13]. Therefore, a lighter and eco-friendly shielding plate with an appropriate thickness and size would be more convenient to protect patients and medical staff in medical institutions. The metallic shielding plates primarily used for radiation shielding in such institutions can be used as shields during X-ray imaging and shielding parts inside medical devices, and for radiation-shielding cars used to transport radionuclides and nucleation injection cylinders used in nuclear medicine [14]. A processing method that retains strength and shielding performance is essential for the manufacturing of such products. For a tungsten-based shielding plate, it is necessary to establish a standard for the shielding performance according to thickness, and the most important aspect in the manufacturing process is the reproducibility of the shielding performance [15]. The shielding performance and lead equivalence of a previous lead shield were evaluated based on its thickness [16]. Therefore, it would also be possible to determine the shielding performance of the tungsten equivalent (mmW) with respect to its thickness, similar to that of an aluminum (mmAl) or lead equivalent (mmPb). In recent times, powder metallurgy has been widely applied in the production of tungsten shields with specific shapes [17; 18]. Powder metallurgy is a method wherein particles are sintered using heat at 1800 \({}^{\circ}\)C or higher. Because the powder purity and particle size of tungsten directly affect its density, the processing design of the initial particles affects the shielding performance [19; 20; 21]. In addition, new tungsten machining methods must be considered for application in small medical-device-shielding components, nuclear syringe cylinders, and shielding linings of special shielded suits [22]. In this study, the rolling method, which is a tungsten-plate-based thin-film processing method, was applied instead of conventional powder metallurgy to manufacture radiation-shielding plates used in hospitals [23]. Two types of rolling methods are used for manufacturing pure tungsten plates: cold and hot rolling. The former is performed at 800-1000 \({}^{\circ}\)C, and the latter ranges from 1550 \({}^{\circ}\)C to 1900 \({}^{\circ}\)C or higher [24; 25]. In the rolling process, pre-annealing is utilized only during hot rolling, and forging is performed up to a predetermined thickness for a certain duration [26]. In this study, an experiment was performed with a tungsten plate of the same thickness to find the difference in shielding performance depending on the applied rolling method for the plate manufacturing.