• Journal of the Korea Convergence Society
• /
• v.8 no.8
• /
• pp.147-154
• /
• 2017

The purpose of this study is to calculate and compare administered activities(MBq) and effective dose(mSv) of the various pediatric dose formulas of pediatric nuclear medicine and to provide base data for the criteria of the optimal administered activities. This study compares dosages and effective doses of 5 types of pediatric dose formulas(Clark rule, Area rule, Webster rule, Young rule, Solomon(Fried) rule) based on the dosage for adults of 2 types of radiopharmaceuticals($^{99m}Tc$-MDP, $^{99m}Tc$-Pertechnetate). The administered activities in adults, which is the criteria for calculating the Pediatric administered activities, used the value from the 'Nuclear Medicine' written by J-G Jeong & M-Ch Lee. and the administered activities by the radioactivity per effective dose(mSv/MBq) of the radiopharmaceuticals for calculating the effective dose used the value from ICRP 80 and the UNSCEAR 2008 Report. As a result of the study, the output of Young rule is the lowest, and its difference between other formulas is from minimum 1.7 times to maximum 3,4 times. The difference between administered activities of $^{99m}Tc$-MDP is maximum 309.9MBq and the effective dose is 3.76mSv. $^{99m}Tc$-Pertechnetate showed the figure at the maximum 154.9MBq and the effective dose has a difference of 5.50mSv. Since the pediatric dose formulas differ not only in administered activities but also in effective doses, the optimal administered activities have to be developed for optimization of medical radiation.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.4
• /
• pp.362-367
• /
• 1999

Purpose: We conducted this study to evaluate the role of dacryoscintigraphy in the diagnosis and treatment of pediatric patients with epiphora. Materials and Methods: In 58 patients aged from 2 months to 15 years (mean age $2.8{\pm}2.3$ years), dacryoscintigraphy was performed using a gamma camera with 4 mm pinhole collimator. We correlated symptoms with dacryosicntigraphic findings in all patients. In 37 patients who underwent ophthalmologic procedures, we analyzed the agreements of dacryoscintigraphic findings with the operation. Results: High rates of agreements between epiphora and obstruction on dacryoscintigraphy (69/72, 95.8%), and between scintigraphic obstructive findings and operation sites (44/47, 93.6%) were noted. Nine of foully-four (20.5%) asymptomatic eyes showed obstructive findings on dacroscintigraphy. Conclusion: In pediatric patients with epiphora, dacryoscintigraphy is a useful tool not only in diagnosing nasolacrimal duct obstruction but also in making a decision for therapeutic procedures.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.3
• /
• pp.171-175
• /
• 2008

Purpose: There have been something difficulties in locating focuses and quantitative analysis in case of pediatric patients because of the relatively small body compared to adults. This author of this study, therefore, evaluated the usefulness of DFOV (Display Field Of View) according to its changes in PET/CT image reconstruction by means of the phantom experiment and pediatric patients examination. Materials & Methods: 0.023 MBq/cc of $^{18}F$-FDG was put into the uniform NU2-94 phantom, and then emission scan was acquired for 10 minutes. For reconstruction, DFOV values were changed to 50, 45, 40, 35, 30, and 25 cm respectively. As for patient images, 20 patients who were diagnosed as the one or suspicion of the children tumor are targeted from Oct 2007 to Jan 2008. For image reconstruction, 50 cm was the basis of DFOV, and the value was adjusted to DFOV 45 cm to 25 cm respectively. In the phantom and the reconstruction image of pediatric patients, the changes in pixel size and $SUV_{max}$ according to DFOV changes were analyzed. Results: As DFOV decreased to 50, 45, 40, 35, 30, and 25 cm by means of the phantom, the pixel size was changed to 3.906, 3.515, 3.125, 2.734, 2.343, and 1.953 mm respectively. Besides, as a result of reconstruction DFOV in images of pediatric patients to 50, to 25 cm, the different values of $SUV_{max}$ are shown as 3.3, 7.3, 12, 14, 18% and 2.6, 4.3, 5.0, 7.0, 10.0% on respectively when 50 cm was the standard. Conclusion: In $SUV_{max}$ using the phantom, as DFOV decreased every 5 cm, the mean value gradually increased. With 50 cm as the standard, the increase rates were 3.7, 6.5, 11.2, 19.5, and 32.1% respectively. As for pediatric patients image too, as DFOV decreased, the rates increased as in the phantom experiment. In image reconstruction, since DFOV decrease regardless of matrix size change reduced the pixel size, the image quality can be improved. This would be more useful than reconstruction and enlarge images of pediatric patients in the same way of examining adults. However, when the value of 35 cm DFOV was applied, this may result in truncated artifact, and thus the application should be properly controlled. Change of DFOV may produce better image for pediatric patients, but changes of SUV values according to DFOV change should be considered in reading.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.3
• /
• pp.192-200
• /
• 2008

To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.15 no.2
• /
• pp.53-59
• /
• 2011

Purpose: To evaluate the dosimetry and image of very low does CT attenuation correction for phantom using pediatric PET/CT. Materials and methods: three PET / CT scanners (Discovery STe, BiographTruepoint 40, Discovery 600) as a child-size acrylic phantom and ion chamber dosimeter (Unfous Xi CT, Sweden) using a CT image acquisition parameters (10, 20, 40, 80, 100, 160 mA; 80, 100, 120, 140 kVp) by varying the depth dose and evaluate $CTDI_{vol}$ value. And each attenuation corrected PET/CT images used NEMA PET Phantom$^{TM}$ (NU2-1994) was evaluated by SUV. Results: Abdominal diagnosis CT dose in general pediatric (about 10 ages) parameter (100 kVp, 100 mA) than very low dose CT parameter (80 kVp, 10 mA) at the depth dose was reduced approximately 92%, $CTDI_{vol}$ was reduced to about 88%. Each CT attenuation corrected parameters PET images showed no change in the value of SUV. Conclusion: for pediatric patients, PET/CT scan can be obtained with very low dose attenuation correction CT (80 kVp, 10 mA), and such attenuation correction CT dose was reduced 100 fold than diagnosis CT dose. PET / CT scan used very low dose CT attenuation correction in pediatric patients can be helpful in reducing radiation dose.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.13 no.1
• /
• pp.47-50
• /
• 2009

Purpose: Presently, any exact standard of radiopharmaceutical doses in pediatric nuclear medicine doesn't exist in the universe. So hospitals are following by manual of vial kit or guidelines of America and Europe based on recommended adult doses adjusted for body mass (MBq/kg) or body surface area (MBq/$m^2$). However, especially for children younger than 1 year and heavier than 50 kg, it's hard to estimate exact dosage for those children. Materials and Methods: In order to obtain objective data of multipliers for pediatric studies, we surveyed 4 major hospitals in Korea. After receiving feedbacks, we changed dosage to multiplier. And we compared multipliers of Korea to America's and Europe's. Results: Most hospitals in Korea are following by body mass formula (MBq/kg). On the other hand, standards don't include proper factors for a child younger than 1 year and heavier than 50 kg. Multipliers for 3 kg children who are injected lower doses than needed are America:0.12, Europe:0.09, Korea:0.05, multipliers for 30 kg children who are injected proper doses are America:0.58, Europe:0.51, Korea:0.45 and multipliers for 60 kg children who are injected more doses than needed are America:0.95, Europe:0.95, Korea:0.91. Conclusions : Through the survey, when calculating doses for children, usually output doses are based on adult doses adjusted for body mass (MBq/kg) but research has shown that standards of all of the compared standards don't reflect exact multipliers for children younger than 1 year and heavier than 50 kg. Therefore, we should give an effort to reduce needless radiation exposure in children by establishing a proper doses standard and also developing better image reconstruction software.

• Journal of Biomedical Engineering Research
• /
• v.36 no.4
• /
• pp.123-127
• /
• 2015

Recently, new gamma camera systems enabling low radiation dose imaging have been developed. We reviewed the recent development of these low dose gamma camera systems including high sensitivity detectors, device structures, noise reduction filters, efficient image reconstruction algorithms, low dose protocols, and so on. It is expected that further technological advances reduce both radiation dose and imaging time in gamma camera imaging especially for radiation-sensitive patients such as pediatric patients.

• Childhood Kidney Diseases
• /
• v.26 no.2
• /
• pp.111-115
• /
• 2022

Kleefstra syndrome is a rare genetic disease characterized by mental retardation, hypotonia, and a characteristic facial appearance. Furthermore, in some cases, Kleefstra syndrome is associated with various anorectal and genitourinary complications, including imperforated anus, vesicoureteral reflux, hydronephrosis, and chronic kidney disease. Herein, we present a case of Kleefstra syndrome with recurrent urinary tractinfections associated with vesicoureteral reflux and rectourethral fistula, which was treated by a multidisciplinary approach.

• Childhood Kidney Diseases
• /
• v.26 no.1
• /
• pp.1-10
• /
• 2022

Congenital isolated hydronephrosis encompasses a spectrum of physiologic states that spontaneously resolve and pathologic obstruction that necessitates surgical intervention. Distinguishing patients whose condition will resolve, those who will require stringent follow-up, and those who will eventually need surgical intervention present a challenge to clinicians, particularly because no unified guidelines for assessment and follow-up have been established. The recognition of the natural course and prognosis of hydronephrosis and a comprehensive understanding of the currently proposed consensus guidelines may aid in multidisciplinary treatment and in providing proper counseling to caregivers. In this review, we aimed to summarize the literature on the grading systems and management strategies for congenital isolated hydronephrosis.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.2
• /
• pp.85-90
• /
• 2007

Acute event in cerebrovascular disease is the second most common cause of death in Korea following cancer, and it can also cause serious neurologic deficits. Understanding of perfusion status is important for clinical applications in management of patients with cerebrovascular diseases, and then the attacks of ischemic neurologic symptoms and the risk of acute events can be reduced. Therefore, the normal vascular anatomy of brain, various clinical applications of acetazolamide-enhanced brain perfusion SPECT, including meaning and role of assessment of vascular reserve in carotid stenosis before procedure, in pediatric Moyamoya disease before and after operation, in prediction of development of hyperperfusion syndrome before procedure, and in prediction of vasospasm and of prognosis in subarachnoid hemorrahge were reviewed in this paper.