Monte Carlo simulation of radiation dose to infant patients from urine-contaminated diapers during diuretic renal scintigraphy.

Objectives: To quantify the radiation doses received by infants from urine-contaminated diapers during diuretic renal scintigraphy examinations, a Monte Carlo dose simulation method integrated with advanced image processing techniques was proposed and evaluated.

Methods: Organ-specific dose coefficients with radiation sourcing from diapers were calculated by a Monte Carlo dose simulation package (GAMOS 6.1.0) with the International Commission on Radiological Protection reference infant phantoms modified to include diapers as computational phantoms. Doses absorbed by organs of patients in the exams were estimated by multiplying the computed organ-specific dose coefficients by the cumulative activities of contaminated diapers estimated from time-series renal scintigraphy images. Data from 10 infant patients (five male and five female) who underwent renal scintigraphy exams were evaluated.

Results: The dose coefficients of representative organs (mGy/Bq.s) were calculated to be 2.82E-13 (total body), 4.84E-13 (penis), 6.48E-14 (testes), 4.35E-14 (scrotum), and 6.75E-15 (prostate) for male infants; 4.37E-14 (total body), 6.71E-13 (uterus), 5.11E-14 (bladder), 3.19E-15 (ovaries), and 2.77E-15 (sigmoid) for female infants. Absorbed doses (mGy) in male patients from the evaluated patient data were quantified to be 1.94 (total body), 4.45E-01 (testes), 3.32E-01 (penis), 2.98 E-01 (scrotum), and 4.63 E-02 (prostate), and in female patients were 1.18 (total body), 1.81E-01 (uterus), 1.38 E-01 (bladder), 8.62E-02 (ovaries), and 7.49 E-02 (sigmoid).

Conclusion: The study proposed and evaluated a method to quantify radiation dose from urine-contaminated diapers during renal scintigraphy exams in infants. The results indicated that the radiation dose from the contaminated diaper cannot be ignored, especially for radiation-sensitive organs such as testes and ovaries.