# Evaluation of Operator and Patient Doses after Irradiation with Handheld X-ray Devices
## 2 Methods and Materials  
In the present study, facilities from Ankara University Faculty of Dentistry and Ataturk University Faculty of Medicine's Biophysics Department were employed. The focus was primarily on the handheld X-ray device, whose adoption has surged in recent times. The objective was to ascertain and compare the radiation exposure to selected organs and tissues in both the patient and the operator. For the purpose of this study, three distinct handheld X-ray devices were employed to irradiate the TLDs. Firstly, the NOMAD Pro 2 TM X-ray device (Aribex, Inc., Charlotte, NC, USA) was utilized. This device boasts specifications of 60 kVp, 2.5 mA power, 1.5 mm Al total filtration, and a 0.4 mm focal spot size. Weighing in at 2.5 kg, it has a cone length of 20 cm and requires a two-hand operation. Its digital timer display facilitates adjustments ranging from 0.02-1.00 s with 0.01 s increments. The second instrument was the Rextar X (Posdion Co., Seoul, Korea). Characterized by 70 kVp, 2 mA power, 1.5 mm Al total filtration, and 0.4 mm focal spot size, it weighs 1.6 kg and has a 6 mm circular diameter with a 4 cm cone length. Its ergonomic design is tailored for one-handed operation. Its timer, with a digital interface, can be modulated between 0.01 and 1.3 s, adjustable in 0.01 s segments. The third handheld in consideration was the Diox-602 X-ray device (DigiMed, Seoul, Korea). This device, presenting a specification of 60 kVp, 2 mA power, 1.6 mm Al total filtration, and 0.8 mm focal spot size, weighs 1.8 kg. Additionally, it has a 6 mm circular diameter and a 10 cm cone length, requiring bipedal operation. Its digital timer allows for adjustments ranging from 0.01 to 1.6 s in 0.01 s increments. A soft and hard tissue equivalent maxillofacial phantom, ATOM(r) Max Dental and Diagnostic Phantom, model 711 HN (CIRS Inc., Norfolk, VA, USA), was used to simulate the patient's cranial structure. To ensure precision in positioning during the irradiation process, this phantom head was paired with a tripod, facilitating rotational adjustments across the x, y, and z axes. Representing the operator was a life-sized mannequin, standing approximately 185 cm (See Figure 1). All experimental procedures were meticulously orchestrated within the radiological laboratory of Ankara University's Faculty of Dentistry. For the paramount safety of the personnel, irradiation was executed from behind a lead screen using a 2.5 m extended rod. Prior to initiating the experiments, thorough radiation safety checks were undertaken to ensure the assembly's functionality and the adequacy of the radiation protection measures. To measure the equivalent doses to the operator's body and to estimate the doses as recorded by an occupational dosemeter, pre-calibrated thermoluminescent dosemeters (TLDs) (LiF: Mg, Cu, P, Harshaw Chemical, Solon, OH, USA) were placed on the mannequin and the phantom head (Figures 1 and 2). TLD-100H dosimeters are in the form of a 4.5 mm diameter and 0.89 mm thick disk (chip) and are sensitive to small quantities of radiation down to 1 uGy. Then, 100 TLD-100H dosimeters to be used in the experiments were heated at 225 \({}^{\circ}\)C for 10 min, and their stored energy was discharged. After numbering from 1 to 100, it was placed in a 3 mm thick plexiglass container. The dosimeters were irradiated with an X-ray source (periapical X-ray device/Belmont Phot-XII) whose radiation amount was determined using the RTI Black Piranha X-ray Meter device in the environment to receive a homogeneous 1000 \(\upmu\)Gy. During this irradiation, the amount of radiation reaching the vessel was measured as 1000 \(\pm\) 10 \(\upmu\)Gy. Since the amount of radiation given to the dosimeters and the phototube current values read in the TLD-reader device are known, the conversion coefficients (Reader Calibration Factor--RCF) of the dosimeters used to convert the phototube current to the amount of absorbed radiation were calculated for the device.