## 3 Results
#### 3.1.1 Environmental Radiation Exposure in the \({}^{99m}\)Tc-MDP Bone Scintigraphy Workplaces
Results are presented as mean \(\pm\) standard deviation (\(n=30\)). These guidelines recommend an average effective dose limit of 20 mSv over five consecutive years, with a maximum allowable annual exposure of 50 mSv in any single year. The occupational dose rate of 25 \(\upmu\)Sv/h shown in the figure was calculated, assuming a standard 40 h working week over 50 weeks per year. All areas are within the guideline; however, close monitoring of the injection room, SPECT room, patient post-injection room, patient observation area, and SPECT/CT rooms is necessary. The highest dose rate of 13.75 \(\upmu\)Sv/h was recorded in the patient post-injection waiting room. Figure 4: Evaluation of environmental radiation exposure within controlled areas of a nuclear medicine center during \({}^{99\text{m}}\)Tc-MDP bone scintigraphy procedure. The data are presented as mean \(\pm\) standard deviation (\(n=30\)). Figure 3: The nuclear medicine floor plan illustrates the layout and arrangement of equipment and workstations designed to prepare and handle the \({}^{99\text{m}}\)Tc-MDP radiopharmaceutical. This layout includes designated controlled areas essential for assessing radiation doses in nuclear medicine procedures. Key areas, such as the SPECT/CT and SPECT rooms, are prominently featured alongside specialized rooms, including the hot laboratory, radioactive waste room, and injection room. The plan also organizes staff and patient movement through specific spaces, such as pre-injection, post-injection, and consultation rooms, thereby ensuring a safe and efficient workflow throughout the nuclear medicine facility. Time and Dose-Response Dependencies of OSL Dosimeters in the \({}^{99m}\)Tc-MDP Bone Scintigraphy: An Anthropomorphic Phantom Study  
This investigation highlights the critical role of using phantoms to determine the energy response calibration for personal monitoring dosimeters, which measure radiation exposure across different body parts (Figure 5) [37]. An RSD anthropomorphic head phantom with a complete cervical spine (C1-C7) was used for Hp(3) eye lens dose equivalent measurements. An RSD anthropomorphic thorax phantom is used for Hp(10) deep dose equivalent and an anthropomorphic hand phantom for Hp(0.07) shallow dose equivalent measurements. At the 0 h mark, the ring finger at 2.88 uSv and palm at 2.78 uSv exhibit the highest levels of radiation exposure, likely due to their proximity to the radiation source. In contrast, the eye lenses display significantly lower initial values (left 0.8495 uSv and right 0.9087 uSv). By 6 h, the radiation exposure values for all body parts decrease by approximately 50%, with the thumb reducing to 1.2207 uSv and the ring finger to 1.3993 uSv, reflecting the natural decay of radiation energy [38]. At 12 h, further reductions are observed, with values for the fingers and palms ranging from 0.6534 uSv to 0.7536 uSv, while the eye lenses decrease to 0.2185 uSv (right) and 0.2056 uSv (left), indicating continued decay of \({}^{99m}\)Tc-MDP. Furthermore, the consistent decrease in exposure over time underscores the importance of calibrating dosimeters to accurately track time-dependent variations in radiation energy. The differences in exposure levels across body parts highlight the need for optimal dosimeter placement, particularly on areas such as the fingers and palms, which are more likely to experience direct exposure. These findings are crucial for calibration, ensuring that dosimeters can reliably detect radiation across different energy levels and over extended periods. The initial variations in exposure across different body parts, followed by their steady reduction, provide essential data for establishing dose-response curves, which are fundamental to the calibration process. Furthermore, the time-dependent clearance of radiation, whether due to natural metabolic processes or shielding interventions, must be accurately captured by dosimeters to ensure proper monitoring of personnel exposure [39].