## 2 Materials and Methods
### Ethical Considerations
The calibration process adhered to the guidelines set out by the Japanese Standards Association (JIS) Z 4345-3, which included measuring uncertainty [28]. Personnel Dose Assessment from Radiation Exposure during Preparation and Handling of 99 mTc-MDP Radiopharmaceutical  
Continually evaluating the level of radiation exposure in nuclear medicine-restricted areas is essential to guarantee the safety of staff and the general public. Publication 103 of the International Commission on Radiological Protection (ICRP) for nuclear medicine personnel set a limit of 20 mSv/y (averaged over five consecutive years) and 50 mSv/y in any given year [29]. Many countries have included International Atomic Energy Authority (IAEA) safety standards in their national safety regulations. The IAEA publication GSG-7 Occupational Radiation Protection also provides advice on controlling occupational exposure [30]. Furthermore, the IAEA publication Operational Guidance on Hospital Radiopharmacy provides several recommendations [31]. Before the VR study, staff personnel dose measurements were recorded in the hot lab over 3 days to evaluate the radiation exposure of the nuclear medicine scientist preparing \({}^{99\text{m}}\)Tc-MDP (Figure 2). The data were collected from measurements using nanoDot dosimeters calibrated for the personal dose equivalents Hp(10), Hp(0.07), and Hp(3), as well as technetium dosage estimation. The symbol Hp(d) represents the personal dosage equivalent in soft tissue at a specified depth (d), as defined by the International Commission on Radiation Units and Measurements (ICRU) [32]. The whole-body personal dose equivalent, also known as Hp(10), is a quantity used in individual monitoring to measure effective doses at a depth of 10 mm in tissue. The Hp(0.07) dosage equivalent, commonly known as the skin dose, is the dose to the skin, hands, and feet. Hp(3) is the dose to the skin at a depth of 3 mm for monitoring the eye lens [33]. Using a MicroStar reader (Landauer, Ltd., Glenwood, IL, USA), the nanoDot OSL-based medical dosimeter (Nagase Co., Ltd., Bangkok, Thailand), along with a control, were tested three times for Hp(10), Hp(0.07), and Hp(3). Three measurements from the nanoDot dosimeters that were not exposed to radionuclides were averaged and removed from the measurement readings from the exposed dosimeters to obtain one data point. It was found that the coefficients of variation (CV) of the doses measured by the exposed dosimeters were:  
\[CV(\%)=\left[ \begin{array}{c}SD\\ \frac{SD}{D_{ave}}\end{array} \right]\times 100 \tag{1}\]  
where \(SD\) is the standard deviation of the dose recorded, and \(D_{ave}\) is the average exposure measured by each dosimeter. The recording of personnel dose equivalents was conducted using nanoDot [34], optically stimulated luminescence dosimeters (OSLD) (Landauer nanoDot(tm)), and the dose coefficients of variance (CV) were calculated using Equation (2). Additionally, the reading before preparation and handling of \({}^{99\text{m}}\)Tc-MDP radiopharmaceutical was used as the background value. Figure 2: Personnel dose assessment to evaluate radiation exposure during the preparation and handling of \({}^{99\text{m}}\)Tc-MDP radiopharmaceutical at various body parts, including Hp(0.07) measurements at (**A**) the left thumb, (**B**) the left index finger, (**C**) the left ring finger, (**D**) the left palm, (**E**) the right thumb, (**F**) the right index finger, (**G**) the right ring finger, and (**H**) the right palm; Hp(3) measurements at (**I**) the left eye lens and (**J**) the right eye lens; and Hp(10) measurements for (**K**) the whole body. The mean of three dosimeter readings was used.