Patient Dosimetry in SPECT/CT Lymphoscintigraphy Examinations
Background: Lymphoscintigraphy imaging procedure is performed at the nuclear medicine department to evaluate sentinel lymph nodes for excisional biopsy in patients with melanoma, and to assess the use of the intraoperative gamma probe in the operating room. The objective of this study is to evaluate the radiation dose of patients during lymphoscintigraphy SPECT/CT procedure and to estimate its radiogenic risk. Methods: Of the thirty patients that underwent SPECT/CT in this research, 63.3 % (19 patients) and 36.7 % (11 patients) were females and males, respectively. For SPECT/CT [GE Hualun Medical Systems (Discovery NM/CT 670Pro)]. Results: The effective dose (mSv) per procedure ranges from 0.21 to 0.5 mSv, with an average dose value of 0.22 mSv. The effective dose for CT examination is 0.05 (ranging from 0.04 to 0.1 mSv per procedure). Therefore, the effective dose for CT is lower than that for SPECT by a factor of 5. This radiation risk is equivalent to 5 weeks of natural background radiation exposure. Conclusions: This place it under the category of low radiation risk for cancer, equivalent to 1 cancer case per 105 SPECT/CT lymphoscintigraphy procedures. Moreover, this dose is lower than previously published studies suggesting that the patients were well protected during the entire procedure.