Relationship between the Stimulated Peak Growth Hormone Level and Metabolic Parameters in Children with Growth Hormone Deficiency / 이화의대지

Objectives@#This study investigated the relationship between the stimulated peak growth hormone (PGH) level and comprehensive metabolic markers for glucose and lipid metabolism, and liver steatosis in prepubertal children with GH deficiency (GHD). @*Methods@#Sixty-nine prepubertal children with GHD were divided into overweight/obesity (body mass index [BMI]≥85th percentile) and normal BMI groups. The associations between PGH level and metabolic parameters including homeostatic model assessment-insulin resistance (HOMA-IR), lipid profiles, AST, and ALT were evaluated. @*Results@#The LDL cholesterol level was significantly higher in the overweight/obesity group than in the normal BMI group. PGH level was negatively associated with the BMI SD score (SDS) (r= −0.26, P=0.029) and ALT (r=−0.36, P=0.004) levels, whereas it was positively associated with the HDL-cholesterol (HDL-C) level (r=0.38, P=0.002). In multivariate analyses, PGH level was positively associated with HDL-C level (P=0.002) and negatively associated with ALT level (P=0.028) after adjusting for age, sex, BMI SDS, HOMA-IR, and TG level. @*Conclusion@#PGH level in pre-pubertal children with GHD was positively and negatively associated with HDL-C and ALT, respectively, even if they were within normal range, regardless of BMI.

Relationship Between the Serum FGF21 Level and Growth in Children of Short Stature

Background@#This study investigated the relationship between fibroblast growth factor 21 (FGF21) levels and growth in children with growth hormone deficiency (GHD) and idiopathic short stature (ISS), and the effects of the FGF21 level on response to growth hormone (GH) treatment. @*Methods@#We included 171 pre-pubertal children with a GHD (n = 54), ISS (n = 46), and normal height (n = 71). Fasting FGF21 levels were measured at baseline and every 6 months during GH treatment. Factors associated with growth velocity (GV) after GH therapy were investigated. @*Results@#The FGF21 level was higher in short children than in the controls without significant difference between the GHD and ISS groups. In the GHD group, the FGF21 level was inversely associated with the free fatty acid (FFA) level at baseline (r = −0.28, P = 0.039), however, was positively correlated with the FFA level at 12 months (r = 0.62, P = 0.016). The GV over 12 months of GH therapy was positively associated with the delta insulin-like growth factor 1 level (β = 0.003, P = 0.020). The baseline log-transformed FGF21 level was inversely associated with GV with marginal significance (β = −0.64, P = 0.070). @*Conclusion@#The FGF21 level was higher in children of short stature, both those with GHD and the ISS, than in children with normal growth. The pretreatment FGF21 level negatively affected the GV of children with GH-treated GHD. These results suggest the existence of a GH/FFA/FGF21 axis in children.

Croup as a Manifestation of SARSCoV-2 Omicron Variant Infection in Young Children

Croup is an acute upper respiratory disease primarily caused by the parainfluenza virus.Owing to inflammation and edema of the upper airways, children present with barky cough and stridor, and some may experience respiratory distress. We investigated children aged < 5 years with coronavirus disease 2019 (COVID-19) admitted to two hospitals in Seoul, South Korea, and observed a spike in croup cases during the omicron surge. Among the 569 children admitted from March 1, 2021 to February 25, 2022, 21 children (3.7%) had croup, and the proportion of croup cases was significantly higher during the omicron wave than that during the delta wave (12.4% vs. 1.2%, P < 0.001). With the immediate administration of corticosteroids and epinephrine via nebulizer, the symptoms improved rapidly. During the current omicron surge, careful monitoring of the symptoms of croup in young children is needed for the diagnosis of COVID-19 and its timely management.

The Survey of Recognition about Rehabilitative Robots for Treatmentin Physical Therapists

Purpose@#This study examined the recognition of rehabilitative robots for treatment in physical therapists. @*Methods@#This study surveyed 100 physical therapists in Seoul and Gyeonggi-do using Google Form, an online survey tool. The questionnaire consisted of 21 questions, including eight questions on the general characteristics, 13 questions on the recognition of rehabilitative robots. @*Results@#The general characteristics of the physical therapists showed differences and influences on recognition of rehabilitative robots, and there were statistically significant differences. There were significant differences in the recognition of rehabilitation robots according to general characteristics in gender, age, education degree, type of hospital, average weekly working time, and treatment field. Multiple regression analysis found that gender and the type of hospital influenced the recognition of rehabilitation robots. @*Conclusion@#Physical therapists showed differences in recognition of rehabilitative robots according to their general characteristics, and gender and the type of hospital influence the recognition of rehabilitation robots. Sufficient systematic education programs should be provided, and physical therapists require policy adjustments to increase their accessibility to rehabilitation robots through continuing education.

The Survey of Recognition about Rehabilitative Robots for Treatmentin Physical Therapists

Purpose@#This study examined the recognition of rehabilitative robots for treatment in physical therapists. @*Methods@#This study surveyed 100 physical therapists in Seoul and Gyeonggi-do using Google Form, an online survey tool. The questionnaire consisted of 21 questions, including eight questions on the general characteristics, 13 questions on the recognition of rehabilitative robots. @*Results@#The general characteristics of the physical therapists showed differences and influences on recognition of rehabilitative robots, and there were statistically significant differences. There were significant differences in the recognition of rehabilitation robots according to general characteristics in gender, age, education degree, type of hospital, average weekly working time, and treatment field. Multiple regression analysis found that gender and the type of hospital influenced the recognition of rehabilitation robots. @*Conclusion@#Physical therapists showed differences in recognition of rehabilitative robots according to their general characteristics, and gender and the type of hospital influence the recognition of rehabilitation robots. Sufficient systematic education programs should be provided, and physical therapists require policy adjustments to increase their accessibility to rehabilitation robots through continuing education.

Discrepancies between Glycosylated Hemoglobin and Fasting Plasma Glucose for Diagnosing Impaired Fasting Glucose and Diabetes Mellitus in Korean Youth and Young Adults

BACKGROUND: Glycosylated hemoglobin (HbA1c) has been recommended as a diagnostic test for prediabetes and diabetes. Here, we evaluated the level of agreement between diagnoses based on fasting plasma glucose (FPG) versus HbA1c levels and determined optimal HbA1c cutoff values for these diseases in youth and young adults. METHODS: The study included 7,332 subjects (n=4,129, aged 10 to 19 years in youth group; and n=3,203 aged 20 to 29 years in young adult group) from the 2011 to 2016 Korea National Health and Nutrition Examination Survey. Prediabetes and diabetes were defined as 100 to 125 mg/dL (impaired fasting glucose [IFG]) and ≥126 mg/dL for FPG (diabetes mellitus [DM] by FPG [DMFPG]), and 5.7% to 6.4% and ≥6.5% for HbA1c, respectively. RESULTS: In the youth group, 32.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 72.2% with DMFPG had an HbA1c ≥6.5%. In the young adult group, 27.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 66.6% with DMFPG had an HbA1c ≥6.5%. Kappa coefficients for agreement between the FPG and HbA1c results were 0.12 for the youth group and 0.19 for the young adult group. In receiver operating characteristic curve analysis, the optimal HbA1c cutoff for IFG and DMFPG were 5.6% and 5.9% in youths and 5.5% and 5.8% in young adults, respectively. CONCLUSION: Usefulness of HbA1c for diagnosis of IFG and DMFPG in Koreans aged <30 years remains to be determined due to discrepancies between the results of glucose- and HbA1c-based tests. Additional testing might be warranted at lower HbA1c levels to detect IFG and DMFPG in this age group.

Association between hemoglobin glycation index and cardiometabolic risk factors in Korean pediatric nondiabetic population

PURPOSE: The hemoglobin glycation index (HGI) represents the degree of nonenzymatic glycation and has been positively associated with cardiometabolic risk factors (CMRFs) and cardiovascular disease in adults. This study aimed to investigate the association between HGI, components of metabolic syndrome (MS), and alanine aminotransferase (ALT) in a pediatric nondiabetic population. METHODS: Data from 3,885 subjects aged 10–18 years from the Korea National Health and Nutrition Examination Survey (2011–2016) were included. HGI was defined as subtraction of predicted glycated hemoglobin (HbA1(c)) from measured HbA1(c). Participants were divided into 3 groups according to HGI tertile. Components of MS (abdominal obesity, fasting glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure), and proportion of MS, CMRF clustering (≥2 of MS components), and elevated ALT were compared among the groups. RESULTS: Body mass index (BMI) z-score, obesity, total cholesterol, ALT, abdominal obesity, elevated triglycerides, and CMRF clustering showed increasing HGI trends from lower-to-higher tertiles. Multiple logistic regression analysis showed the upper HGI tertile was associated with elevated triglycerides (odds ratio, 1.65; 95% confidence interval, 1.18–2.30). Multiple linear regression analysis showed HGI level was significantly associated with BMI z-score, HbA1(c), triglycerides, and ALT. When stratified by sex, age group, and BMI category, overweight/obese subjects showed linear HGI trends for presence of CMRF clustering and ALT elevation. CONCLUSIONS: HGI was associated with CMRFs in a Korean pediatric population. High HGI might be an independent risk factor for CMRF clustering and ALT elevation in overweight/obese youth. Further studies are required to establish the clinical relevance of HGI for cardiometabolic health in youth.

Unfavorable Course of Subclinical Hypothyroidism in Children with Hashimoto's Thyroiditis Compared to Those with Isolated Non-Autoimmune Hyperthyrotropinemia

Subclinical hypothyroidism (SCH) is a common problem in pediatric population, and the natural history of SCH varies depending on its etiology. Whether Hashimoto’s thyroiditis (HT) negatively affects the natural course of SCH was investigated in pediatric patients without concomitant diseases. Predictors for levothyroxine medication were also evaluated. Medical records of 109 children with SCH (91 girls, 5−18 years) diagnosed between 2005 and 2014 were retrospectively reviewed. Patients were classified into HT (n = 37) and isolated non-autoimmune hyperthyrotropinemia (iso-NAHT, n = 72). During median 2 years of follow-up, only 10.1% of SCH patients eventually initiated levothyroxine, and HT patients showed a higher probability of requiring levothyroxine medication than iso-NAHT patients (21.6% vs. 4.2%). Underlying HT independently predicted deterioration of thyroid function, leading to levothyroxine medication (hazard ratios [HRs], 4.6 vs. iso-NAHT, P = 0.025). High titers of anti-thyroglobulin antibodies (TGAbs) predicted later medication in the HT group (HRs, 28.2 vs. normal TGAbs, P = 0.013). Most pediatric SCH showed benign and self-remitting courses. Underlying HT significantly increases the risk for levothyroxine medication, especially with high titers of TGAbs.

Factors Associated with the Presence and Severity of Diabetic Ketoacidosis at Diagnosis of Type 1 Diabetes in Korean Children and Adolescents

The aim of this study was to identify the risk factors for presence and severity of diabetic ketoacidosis (DKA) at the onset of type 1 diabetes mellitus (T1DM) in Korean children and adolescents. A retrospective chart review of children and adolescents newly diagnosed with T1DM was conducted in seven secondary and tertiary centers in Korea. Eligible subjects were < 20 years of age and had records on the presence or absence of DKA at the time of T1DM diagnosis. DKA severity was categorized as mild, moderate, or severe. Data were collected on age, height, body weight, pubertal status, family history of diabetes, delayed diagnosis, preceding infections, health insurance status, and parental education level. A total of 361 patients (male 46.3%) with T1DM were included. Overall, 177 (49.0%) patients presented with DKA at T1DM diagnosis. Risk factors predicting DKA at T1DM diagnosis were age ≥ 12 years, lower serum C-peptide levels, presence of a preceding infection, and delayed diagnosis. Low parental education level and preceding infection increased the severity of DKA. These results suggest that alertness of the physician and public awareness of diabetes symptoms are needed to decrease the incidence and severity of DKA at T1DM diagnosis.

Perinatal factors associated with neonatal thyroid-stimulating hormone in normal newborns

PURPOSE: This study was to evaluate the effect of neonatal, maternal, and delivery factors on neonatal thyroid-stimulating hormone (TSH) of healthy newborns. METHODS: Medical records of 705 healthy infants born through normal vaginal delivery were reviewed. Neonatal TSH levels obtained by neonatal screening tests were analyzed in relation to perinatal factors and any associations with free thyroxine (FT4) and 17-α hydroxyprogesterone (17OHP) levels. RESULTS: An inverse relationship was found between TSH and sampling time after birth. Twin babies and neonates born by vacuum-assisted delivery had higher TSH levels than controls. First babies had higher TSH levels than subsequent babies. Birth weight, gestational age, maternal age and duration from the rupture of the membrane to birth were not related to neonatal TSH. There were no significant differences in TSH level according to sex, Apgar scores, labor induction, the presence of maternal disease and maternal medications. There was a positive association between TSH and 17OHP level but not between TSH and FT4 level. Multiple linear regression analyses showed that sampling time, mode of delivery, birth order, and 17OHP level were significant factors affecting neonatal TSH level. CONCLUSION: Neonatal TSH levels of healthy normal newborns are related with multiple factors. Acute stress during delivery may influence the neonatal TSH level in early neonatal period.

Perinatal factors associated with neonatal thyroid-stimulating hormone in normal newborns

PURPOSE: This study was to evaluate the effect of neonatal, maternal, and delivery factors on neonatal thyroid-stimulating hormone (TSH) of healthy newborns. METHODS: Medical records of 705 healthy infants born through normal vaginal delivery were reviewed. Neonatal TSH levels obtained by neonatal screening tests were analyzed in relation to perinatal factors and any associations with free thyroxine (FT4) and 17-α hydroxyprogesterone (17OHP) levels. RESULTS: An inverse relationship was found between TSH and sampling time after birth. Twin babies and neonates born by vacuum-assisted delivery had higher TSH levels than controls. First babies had higher TSH levels than subsequent babies. Birth weight, gestational age, maternal age and duration from the rupture of the membrane to birth were not related to neonatal TSH. There were no significant differences in TSH level according to sex, Apgar scores, labor induction, the presence of maternal disease and maternal medications. There was a positive association between TSH and 17OHP level but not between TSH and FT4 level. Multiple linear regression analyses showed that sampling time, mode of delivery, birth order, and 17OHP level were significant factors affecting neonatal TSH level. CONCLUSION: Neonatal TSH levels of healthy normal newborns are related with multiple factors. Acute stress during delivery may influence the neonatal TSH level in early neonatal period.

Clinical and radiological features of pituitary stalk lesions in children and adolescents

PURPOSE: The diagnosis of pituitary stalk lesion has been based on clinical feature, radiologic assessment for its critical location and role. This study aimed to investigate clinical symptoms, endocrine disturbance, magnetic resonance imaging (MRI) findings of pituitary stalk lesions in children and adolescents and to evaluate differences between neoplastic lesions with the others. METHODS: We performed a retrospective review of patients under 18 years old with pituitary stalk lesions diagnosed at the Seoul National University Children's Hospital between 2000 and 2013, by a text search for head MRI reports by using 'pituitary stalk', 'infundibulum', and 'infundibular stalk', as keywords. RESULTS: For the 76 patients, sixteen patients (21.1%) had congenital lesions, and 52 (68.4%) had neoplasms. No inflammatory lesions were found. Diabetes insipidus (DI) was the most common endocrine defect, diagnosed in 38 patients (50%). There was male predominance especially in neoplastic group. Thickened pituitary stalk was, but enhancement of lesion was not, associated with neoplasm. DI was more prevalent in neoplastic stalk lesions. Anterior pituitary dysfunction such as growth hormone and adrenocorticotropic hormone deficiencies were less prevalent in neoplastic lesions of pituitary stalk. CONCLUSION: In conclusion, the etiology of pituitary stalk lesions in children and adolescents is diverse and different from that in adults. Neoplastic pituitary stalk lesions can be differentiated from nonneoplastic lesions by systemic evaluation of clinical, hormonal, radiological findings.

Growth after Hematopoietic Stem Cell Transplantation in Children with Acute Myeloid Leukemia

Previous studies have shown that hematopoietic stem cell transplantation (HSCT) may result in growth impairment. The purpose of this study was to evaluate the growth during 5 yr after HSCT and to determine factors that influence final adult height (FAH). We retrospectively reviewed the medical records of acute myeloid leukemia (AML) patients who received HSCT. Among a total of 37 eligible patients, we selected 24 patients who began puberty at 5 yr after HSCT (Group 1) and 19 patients who reached FAH without relapse (Group 2). In Group 1, with younger age at HSCT, sex, steroid treatment, hypogonadism and hypothyroidism were not significantly associated with growth impairment 5 yr after HSCT. History of radiotherapy (RT) significantly impaired the 5 yr growth after HSCT. Chronic graft-versus-host disease (cGVHD) only temporarily impaired growth after HSCT. In Group 2, with younger age at HSCT, steroid treatment and hypogonadism did not significantly reduce FAH. History of RT significantly reduced FAH. Growth impairment after HSCT may occur in AML patients, but in patients without a history of RT, growth impairment seemed to be temporary and was mitigated by catch-up growth.

Influence of Body Mass Index on the Growth Hormone Response to Provocative Testing in Short Children without Growth Hormone Deficiency

Obesity and its related factors are known to suppress the secretion of growth hormone (GH). We aimed to evaluate the influence of body mass index (BMI) on the peak GH response to provocative testing in short children without GH deficiency. We conducted a retrospective review of medical records of 88 children (2-15 yr old) whose height was less than 3 percentile for one's age and sex, with normal results (peak GH level > 10 ng/mL) of GH provocative testing with clonidine and dopamine. Peak stimulated GH level, height, weight, pubertal status and serum IGF-1 level were measured. Univariate analysis showed that the BMI standard deviation score (SDS) correlated negatively with the natural log (ln) of the peak stimulated GH level (ln peak GH). BMI SDS did not correlate significantly with sex, age, pubertal status, or ln IGF-1 level. BMI SDS correlated negatively with ln peak GH level induced by clonidine but not by dopamine. In stepwise multivariate regression analysis, BMI SDS was the only significant predictor of ln peak GH level in the combination of tests and the clonidine test, but not in the dopamine test. In children without GH deficiency, BMI SDS correlates negatively with the peak GH level. BMI SDS should be included in the analysis of the results of GH provocation tests, especially tests with clonidine.

The Influence of Body Mass Index on Luteinizing Hormone Levels after Gonadotropin-Releasing Hormone Stimulation in Girls with Precocious and Advanced Puberty

PURPOSE: The aim of this study was to investigate the influence of body mass index (BMI) on the level of peak luteinizing hormone (LH) after gonadotropin-releasing hormone (GnRH) stimulation in girls with central precocious puberty (CPP) and advanced puberty (AP). METHODS: This study conducted a retrospective review of the medical records of 113 girls (7 to 9 years old; 24 CPP, 89 AP) who underwent a GnRH stimulation test. The following parameters were evaluated: chronologic age (CA), bone age (BA), the difference between BA and CA (BA-CA), height, weight, BMI, and the levels of basal LH, peak LH, basal follicle stimulating hormone (FSH), peak FSH, and basal estradiol. RESULTS: The peak LH level was negatively correlated with weight-standard deviation score (SDS) and BMI-SDS; furthermore, the peak LH level was positively correlated with both basal and peak FSH levels. Using multivariate analysis, BMI-SDS was found to be a significant factor in predicting peak LH levels after GnRH administration. When the subjects were divided into four groups by quartile of peak LH level, the mean BMI-SDS of the highest LH group was significantly lower than the mean BMI-SDS of the lowest LH group. CONCLUSION: LH levels rise after GnRH administration is blunted in precocious and advanced pubertal girls with high BMI. The impact of BMI on the GnRH stimulation test should be considered when evaluating sexual precocity in girls.

Urinary 6-sulfatoxymelatonin level in girls and its relationship with obesity / 소아과

PURPOSE: Short sleep duration is associated with obesity. Urinary 6-sulfatoxymelatonin (6-OHMS), the principal metabolite of melatonin, is closely related with sleep. We evaluated the difference in urinary 6-OHMS levels between obese girls and normal weight girls, and the relationship of urinary 6-OHMS with other hormones regulating body weight and metabolism. METHODS: A total of 79 girls (6.3 to 12.4 years) were included in this study, of whom 34 were obese; 15, overweight; and 30, normal-weight. We examined their pubertal status and bone age. Fasting serum levels of total ghrelin, leptin, insulin, and first morning urinary 6-OHMS were measured. Homeostatic model assessment-insulin resistance (HOMA-IR) was calculated from the fasting insulin and glucose levels. RESULTS: There was no significant difference in the creatinine adjusted 6-OHMS levels between the obese girls and the control group. Urinary 6-OHMS did not show any correlations with body mass index (BMI), BMI percentile, total ghrelin, leptin, and HOMA-IR. Negative correlations were found between urinary 6-OHMS levels and chronological and bone ages. CONCLUSION: Our results suggest that melatonin production is not reduced consistently in obese girls.

Insulin-Like Growth Factor 1 Actions in Developing Brain and the Interaction with Wnt Pathway

Insulin like growth factor (IGF)-1 signaling through type 1 IGF receptor (IGF1R) is essential to the normal growth and development of the central nervous system. IGF-1 stimulates proliferation of neural stem cells and neural progenitors. IGF-1 also promotes survival and differentiation of neurons and oligodendrocytes, including neuritic outgrowth, synaptogenesis, and myelin production. The phosphatidylinositol 3 kinase (PI3)-Akt pathway and mitogen-activated protein (MAP) kinase pathway are two predominant mediators of IGF1-IGF1R signaling in neural cells. beta-catenin, a key molecule of the canonical Wnt signaling pathway, is also a downstream target of PI3-Akt-glycogen synthase kinase 3beta (GSK3beta) pathway. IGF-1 signaling through IGF1R interacts with canonical Wnt pathway at the levels of GSK3beta and beta-catenin rather than at the levels of Wnt ligands and Frizzled receptors to promote neural proliferation in developing central nervous system.

The Clinical Characteristics of Idiopathic Hypopituitarism in Children and Adolescents / 대한소아내분비학회지

PURPOSE: The purpose of this study was to evaluate the clinical evolution and endocrine features of idiopathic hypopituitarism. METHODS: We reviewed the medical records of 33 patients with idiopathic hypopituitarism who had been followed up from 1982 to 2008, attained their adult final height, and received appropriate hormonal replacement therapy. RESULTS: 28 of these patients (85%) were male, 26 patients (79%) were delivered by breech presentation, and 18 (55%) were firstborns. The mean age at diagnosis was 10.1 +/- 4.6 years, and bone age was delayed a mean of 4.9 +/- 3.0 years. The mean standard deviation score (SDS) for height at diagnosis was -3.6 +/- 2.9. Deficiencies of pituitary hormones were observed in the following order of frequency: growth hormone (100%), thyroid-stimulating hormone (97.0%), luteinizing hormone/follicle - stimulating hormone (81.8%), adrenocorticotropic hormone (45.5%), and antidiuretic hormone (12.1%). Deficiencies of 4 hormones were observed in 14 (42.4%); 3 hormones, in 11 (33.3%); 2 hormones, in 5 (18.2%); and 5 hormones, in 2 (6.1%). Spontaneous onset of puberty occurred in 6 boys (21.4%), and there were no significant differences in the clinical presentations of pituitary hormone deficiency between these boys and those with gonadotropin-releasing hormone deficiency. CONCLUSION: Idiopathic hypopituitarism should be considered in patients of short stature who are delivered by breech presentation, and their hormone levels should be monitored periodically.

The Clinical Characteristics of Idiopathic Hypopituitarism in Children and Adolescents / 대한소아내분비학회지

PURPOSE: The purpose of this study was to evaluate the clinical evolution and endocrine features of idiopathic hypopituitarism. METHODS: We reviewed the medical records of 33 patients with idiopathic hypopituitarism who had been followed up from 1982 to 2008, attained their adult final height, and received appropriate hormonal replacement therapy. RESULTS: 28 of these patients (85%) were male, 26 patients (79%) were delivered by breech presentation, and 18 (55%) were firstborns. The mean age at diagnosis was 10.1 +/- 4.6 years, and bone age was delayed a mean of 4.9 +/- 3.0 years. The mean standard deviation score (SDS) for height at diagnosis was -3.6 +/- 2.9. Deficiencies of pituitary hormones were observed in the following order of frequency: growth hormone (100%), thyroid-stimulating hormone (97.0%), luteinizing hormone/follicle - stimulating hormone (81.8%), adrenocorticotropic hormone (45.5%), and antidiuretic hormone (12.1%). Deficiencies of 4 hormones were observed in 14 (42.4%); 3 hormones, in 11 (33.3%); 2 hormones, in 5 (18.2%); and 5 hormones, in 2 (6.1%). Spontaneous onset of puberty occurred in 6 boys (21.4%), and there were no significant differences in the clinical presentations of pituitary hormone deficiency between these boys and those with gonadotropin-releasing hormone deficiency. CONCLUSION: Idiopathic hypopituitarism should be considered in patients of short stature who are delivered by breech presentation, and their hormone levels should be monitored periodically.

A Study on Dose Response of MAGAT (Methacrylic Acid, Gelatin Gel and THPC) Polymer Gel Dosimeter Using X-ray CT Scanner / 의학물리

In this study, we evaluated the dose response of MAGAT (Methacrylic Acid Gelatin gel and THPC) normoxic polymer gel dosimeters based on the X-ray CT scanner. To perform this study, we determined the proper ratio of the gel composition and acquired X-ray scan parameters. MAGAT gel dosimeters were manufactured using MAA (MethacrylicAcid) and gelatin of various concentration, irradiated up to 20 Gy. We obtained the 20 CT images from the irradiated gel dosimeters by using on a Phillips Brilliance Big Bore CT scanner with the various scan parameters. This CT images were used to determine the N(CT)-dose response, dose sensitivity and dose resolution As an amount of MAA and gelatin were increase, the slope and intercept were increase in each MAGAT gel dosimeter with various concentration of the N(CT)-dose response curve. The dose sensitivity was 0.38+/-0.08 to 0.859+/-0.1 and increased were amount of the MAA was increased or the gelatin was decreased. However, the change of gelatin concentration was very small compare to MAA. The Dose resolution (D(delta)(95%)) varies considerably from 2.6 to 6 Gy, dependent on dose resolution and CT image noise. The slope and dose sensitivity was almost ident verywith the variation of the tube voltage, tube current and slice thickness in the dose response curve, but the noise (standard deviation of averamalg CT number) was decreased when the tube voltage, tube current and slice thickness are increase. The optimal MAGAT polymer gel dosimeter based on the CT were evaluated to determine the CT imaging scan parameters of the maximum tube voltage, tube current and slice thickness (commonly used in clinical) using the composition ratio of a 9% MAA, 8% gelatin and 83% water. This study could get proper composition ratio and scan parameter evaluating dose response of MAGAT normoxic polymer gel dosimeter using CT scanner.