Wichana Chamroonrat

Elevated MDP activity in the spleen due to fungal infection.

Bone scintigraphic imaging using Tc-99m-methylene diphosphonate (MDP) is one of the most common nuclear medicine procedures. Although MDP can accumulate not only in osseous but also in soft tissue, increased MDP activity in the spleen is relatively uncommon. A 3-year-old girl with recurrent meduloblastoma underwent bone scintigraphy to evaluate for potential osteomyelitis and bone metastases. The images demonstrated increased MDP activity in the spleen in both early blood pool and 3-hour delayed images, which was due to Candida albicans infection.

Early acute hematogenous osteomyelitis detected by bone scintigraphy but not MRI.

Early diagnosis of acute hematogenous osteomyelitis (AHO) is crucial for effective management and to reduce the potential risk of lifelong deformities in pediatric patients. Both bone scintigraphy and MRI as current diagnostic imaging claim their high sensitivity in early detection of the disease. We present a 9-year-old girl patient with AHO in the distal right tibia, which was demonstrated on bone scintigraphy while a subsequent MRI on the same day was negative.

Incidental Gallbladder Cancer Visualized From Posttreatment 131I Whole-Body Scan.

A 72-year-old woman with papillary thyroid cancer post-total thyroidectomy was referred for post-I treatment whole-body scan. Images revealed focal uptake within the gallbladder. Cholecystectomy was subsequently performed, and the pathology report showed well-differentiated adenocarcinoma. Given a history of papillary thyroid cancer, the iodine uptake was reasonably explained as metastasis; however, gallbladder metastasis was extremely infrequent. Literature described the incidental radioiodine retention in the gallbladder as false-positive findings, which can be normal variants or benign hepatobiliary conditions. Primary gallbladder malignancy could be counted for another possibility despite controversial mechanism of uptake.

Factors Affecting Disease-Free Status of Differentiated Thyroid Carcinoma Patients

PURPOSE The study aim was to assess factors that impact on the outcome of radioiodine therapy in patients diagnosed with differentiated thyroid carcinoma (DTC). MATERIALS AND METHODS We performed a retrospective cohort study on 256 patients with DTC who underwent thyroidectomy and received radioiodine therapy during December 2003 to January 2012. All patients were followed up for at least 1 year. They were considered disease- free by the criteria of the revised American Thyroid Association Management Guideline for Patients with Thyroid nodules and DTC (ATA guideline 2009). RESULTS On Cox univariate analysis, factors associated with disease-free status were age<45, stage I tumor, low risk group by histopathology, unifocal tumor involvement, stimulated serum Tg level at 1st dose of radioiodine therapy and no distant metastasis from 1st post-treatment WBS (post RxWBS). On multivariate analysis, stage I tumor and stimulated serum Tg level at 1st dose of radioiodine therapy<30 ng/mL were the significant prognostic factors that increased disease-free rate by 1.73 times and 2.60 times, respectively (P-value<0.05). CONCLUSIONS Factors affecting the outcome of radioiodine therapy in our study were age, stage, risk of recurrence by histopathology, unifocal tumor involvement and 1st postRxWBS findings. From these factors, stage I tumor and stimulated serum Tg level at 1st dose of radioiodine therapy were independent prognostic factors that substantial increase the disease-free rate.

Unexpectedly expected fetal thyroid function on posttreated radioiodine (131I) SPECT/CT of a patient with differentiated thyroid cancer.

We present a 25-year-old woman who has a diagnosis of differentiated thyroid cancer, a 2.5-cm papillary carcinoma in the right lobe, and presence of minimal extrathyroid invasion. 131I ablation and/or treatment of 150 mCi was given orally 3 months after total thyroidectomy. A fetus with radioiodine uptake in the fetal thyroid was unsuspectedly detected by SPECT/CT after 131I treatment.

Absence of FDG uptake in a trauma patient with compromised vasculature as evidence of tissue nonviability.

Abstract: A 29-year-old trauma patient underwent operation of revascularization of the injured left popliteal artery and open reduction internal fixation for the left femoral fractures. Subsequently, the patient developed severe pain in the distal left lower extremity. A CT angiogram revealed patent three-vessels of his left lower extremity. However, an FDG PET/CT demonstrated absence of FDG uptake in the left foot, which suggested soft-tissue nonviability. An amputation was performed the following day. The pathologic examination showed wide-spread necrosis of the entire left foot with extensive dry gangrene, which confirmed FDG PET/CT findings.

Radiation monitoring of non-lead-lined treatment room in general pediatric ward and adjacent areas for high dose 131Iodine-mIBG

Abstract Background: 131I-metaiodobenzylguanidine (mIBG) offers an effectively targeted radionuclide therapy in pediatric patients. According to radiation protection authority in our country, the patient treated with high-dose (>1100 MBq) radioiodine is recommended to stay in the hospital. Hence, this study intends to measure the radiation exposure in nonlead-lined treatment room installing with portable lead shields located in general pediatric ward and surrounding areas. In addition, this study also aims to measure the radiation exposure to the family caregiver in pediatric patients received high dose 131I-mIBG. Methods: Environmental OSL (optically stimulated luminescence) monitoring devices (InLight®, Al2O3:C) were prepared and calibrated by Thailand Institute of Nuclear Technology (TINT). Twenty-five set of OSLs were placed in and surrounded the treatment room. Dose to family caregiver was recorded by digital semiconductor dosimeter (ALOKA PDM-112) also calibrated by TINT. The measurement was carried for four pediatric patients treated with 131IMIBG (activity 3700 – 5500 MBq). Results: The ambient doses equivalent and the dose rate were analyzed, the limit of 10 and 0.5 μSv/h are accepted for radiation worker and member of the public, respectively. The dose rate around the patient bed and toilet were high as expected. Dose rates at the wall of adjacent room and corridor were slightly greater than the public limit (range 1.82 to 4.48 μSv/h). Remarkably, the dose rates at caregiver chair (outside the shielding) were exceeded the limits (30.57 ± 5.69 μSv/h). Consequently, this was correlated with high personal dose equivalent to family caregivers which listed as 175, 1632, 6760 and 7433 μSv for the patient age of 15, 5, 1 and 1 year respectively. Conclusion: These radiation monitoring data provided the important information to manage radiation protection and aware of radiation exposure when using non-lead-lined treatment room in general pediatric ward.