Design of patient rooms and automatic radioiodine-131 waste water management system for a thyroid cancer treatment ward: 'Suandok Model'

The great benefit of (131)I radionuclide treatment for differentiated thyroid cancer (DTC) was acknowledged by the long survival rate. The main requirements for (131)I therapy in hospital were treatment facilities and a radiation safety plan that assured radiation protection and safety to patient, hospital worker, public, and environment.

OBJECTIVE

To introduce the concepts and methods of radiation safety design for a patient's room in a (131)I treatment ward and a system of radioactive waste water management in hospital.

METHODS

The design was based on principles of external and internal radiation protection for unsealed source and radioactive waste management. Planning for treatment facilities was concluded from clinical evidence, physical and physiological information for (131)I, radiation safety criteria, hospital resources and budget. The three phases of the working process were: construction, software development, and radiation safety assessment.

RESULTS

The (131)I treatment facility and automatic radioactive waste water management system was completely implemented in 2009. The radiation waste water management system known as the 'Suandok Model' was highly recommended by the national regulator to hospitals who desire to provide (131)I treatment for thyroid cancer. In 2011, the Nuclear Medicine Division, Chiang Mai University was rewarded by the national authority for a very good radiation practice in development of safe working conditions and environment.

CONCLUSION

The Suandok Model was a facility design that fulfilled requirements for the safe use of high radiation (131)I doses for thyroid cancer treatment in hospital. The facility presented in this study may not be suitable for all hospitals but the design concepts could be applied according to an individual hospital context and resources. People who use or gain benefit from radiation applications have to emphasise the responsibility to control and monitor radiation effects on individuals, communities and the environment.

Radioactive iodine for thyrotoxicosis in childhood and adolescence: treatment and outcomes

OBJECTIVE

The aim of the present study was to evaluate the outcome of radioiodine treatment in thyrotoxicosis in childhood and adolescence.

METHODS

This was a retrospective study of 27 patients (ages 7.2- 19.8 years) with a diagnosis of thyrotoxicosis who received iodine-131 (I-131) treatment from January 2007 to December 2011 in the Nuclear Medicine Division, Department of Radiology, Faculty of Medicine, Chiang Mai University. Gender, duration of antithyroid drug (ATD) treatment, 24-hour I-131 uptake, thyroid weight, total dose and number of treatments with I-131, and thyroid status at 6 months after treatment were recorded.

RESULTS

The outcomes of 27 patients (85.2% female, 14.8% male) treated with radioactive iodine were analyzed to assess the effectiveness of therapy as related to dose and gland size. All children and adolescents received 150 µCi of I-131/g of thyroid tissue (n=27). Six 6 months after treatment, 44.5% of the patients were hyperthyroid, 14.8% were euthyroid, and 40.7% were hypothyroid. Of the 12 cases with hyperthyroidism, 2 cases needed a second dose of I-131 treatment, and they finally reached a hypothyroid state. The patients were classified into 2 groups according to treatment success (euthyroid and hypothyroid) and treatment failure (hyperthyroid). There were no significant differences in age, gender, duration of ATD treatment, 2- and 24-hour I-131 uptake, thyroid weight, and total I-131 dose between these two groups.

CONCLUSIONS

Radioiodine treatment is safe and effective for thyrotoxicosis in childhood and adolescence. It is suitable as a good second-line therapy for patients with severe complications, those who show poor compliance, and those who fail to respond to ATD treatment.

Excretory urography and renal scintigraphy for chronic obstructed kidney: does nonopacity mean nonsalvageability?

INTRODUCTION

This study aimed to ascertain whether nonopacified kidney on excretory urography (also known as intravenous urography [IVU]) indicates nonsalvageability.

METHODS

We retrospectively reviewed 45 adult patients with chronic unilateral urinary tract obstruction, in whom IVU revealed nonopacified kidney on one side but normal excretion on the contralateral side. Affected kidneys with split glomerular filtration rate (GFR) < 10 mL/min/1.73 m2 on 99mTc-diethylenetriaminepentaacetic acid diuretic renal scintigraphy were considered nonsalvageable. Non-function was defined based on cutoff points (< 15% and < 20%) to determine the sensitivity and specificity of differential renal function. Differences in IVU and renal scintigraphy findings, with respect to the duration of delayed filming on IVU, were analysed for significance.

RESULTS

The results of IVU and renal scintigraphy findings for 34 (75.6%) nonopacified kidneys matched, representing nonsalvageable kidneys. Sensitivity and specificity of differential renal function were 76% and 100%, respectively, when the cutoff point for non-function was set at < 15%. Sensitivity and specificity were 97% and 82%, respectively, when the cutoff point was < 20%. There was no significant difference between renal scintigraphy findings and IVU with 2-hour and > 2-hour delayed films (p = 0.96).

CONCLUSION

Although most nonopacified kidneys on IVU were nonsalvageable, a quarter of them were found to be salvageable on renal scintigraphy. Besides split GFR, differential function at cutoff point < 15% could be used to determine non-function of a chronic obstructed kidney when the contralateral kidney is normal. Delayed filming beyond two hours appears unnecessary in ensuring non-excretion on IVU.

Bone mineral density: correlation between the lumbar spine, proximal femur and Radius in northern Thai women

OBJECTIVE

To determine the correlation of bone mineral density (BMD) in lumbar spine, proximal femur and 1/3 radius in northern Thai women.

MATERIALS AND METHOD

The data of this study was collected from the medical records and the BMD results of 885 perimenopausal and postmenopausal women who had the BMD measurement in Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Chiang Mai University between January and December 2007. BMD was measured using dual-energy X-ray absorptiometry (Hologic, QDR-4500C).

RESULTS

Mean age (+/- SD) was 58.7 +/- 9.9 year. The lowest T-score was found 51.6% at lumbar spine (LS), 29.2% at 1/3 radius, 13.8% at femoral neck (FN), 2.9% at total femur (TF) and 2.5% at trochanter region (TR). We found a significant correlation between age, BMI, duration of menopause, and BMD at the LS, TFE FN, TR and 1/3 radius (p < 0.01). The correlation between the BMD measures at LS and TF FN, TR and 1/3 radius were 0.708, 0.667, 0.721 and 0.633, respectively (p < 0 01). Women with perimenopausal status had higher height and BMD values at all five observed sites than postmenopausal women (p < 0.01).

CONCLUSION

The present found a good correlation of the BMD from various skeletal sites. Interestingly, the correlation was found highest between the LS vs. TR and TF vs. TR region. Clearly, estrogen-deficient plays important role on the low BMD values in all skeletal sites.

Bone mineral density in women using depot medroxyprogesterone acetate (DMPA) for at least 2 years compared to a control group: a cross sectional study

OBJECTIVE

To compare the effect of long-term use of depot medroxyprogesterone acetate (DMPA) on bone mineral density (BMD) in Thai women compared to the control.

MATERIAL AND METHOD

A cross sectional study was conducted on Thai women of reproductive age who used DMPA (50 subjects) for contraception for at least 2 years and non-hormonal users (50 subjects). BMD was measured at the lumbar spine, femur and distal radius, and ulna.

RESULTS

There was significantly lower BMD at the lumbar spines in the DMPA group but there was no significant difference in BMD between groups at the femur distal radius, and ulna.

CONCLUSION

Long-term use of DMPA has a negative impact on lumbar spine BMD.

Clinical usefulness of per-rectal portal scintigraphy by Tc-99m pertechnetate in evaluation of the severity of portal hypertension in cirrhotic patients

INTRODUCTION

Variceal haemorrhage is a potentially life-threatening complication in cirrhotic patients. Identification of patients at high risk for bleeding is particularly important. The aim of this study was to determine the clinical usefulness of per-rectal portal scintigraphy (PPS) in the evaluation of the severity of portal hypertension in cirrhotic patients, in terms of correlation between cirrhosis and the parameters of hepatic functional reserve, and identifying the difference of the portal shunt index (PSI) of the bleeding oesophageal variceal (BEV) patients and non-BEV patients.

METHODS

Portal circulations in 67 patients with cirrhosis and oesophageal varices were evaluated by Tc-99m pertechnetate PPS. Tc-99m pertechnetate (550 MBq) was instilled into the upper rectum, and dynamic images of upper abdomen were taken. Radioactivity curves for the liver and the heart were generated sequentially. Through the analysis of these curves, the PSI was determined.

RESULTS

The results, expressed as PSI, were: 11.4 +/- 98.4 percent (mean 66.8) in all 67 cirrhotic patients, 56.4 +/- 27.1 percent in cirrhotic patients without history of BEV, and 74.9 +/- 13.6 percent in cirrhotic patients with history of BEV. The PSI was significantly lower in cirrhotic patients without BEV than those with BEV (p-value equals 0.001). The PSI calculated with this method was correlated with the serum albumin, the serum bilirubin, the prothrombin time, and the Child-Turcotte-Pugh score.

CONCLUSION

Tc-99m pertechnetate PPS has clinical usefulness as a noninvasive method of choice for quantitatively evaluating the severity of portal hypertension in cirrhotic patients.

Breast lymphoscintigraphy for sentinel node identification in breast cancers with clinically-negative axillary nodes

INTRODUCTION

To analyse and determine the clinical value of lymphoscintigraphy for sentinel lymph node (SLN) localisation in woman undergoing surgery for breast cancer, and evaluate the predictive value of SLN versus axillary lymph node (ALN) status in these patients.

METHODS

Preoperative breast lymphoscintigraphy was performed in 35 female patients with breast cancer and clinically-negative ALNs. The mean age was 52.8 years (age range 38 to 73 years). The lymphoscintigraphy was performed using 74 MBq of Tc-99m nanocolloid subdermal injection over the tumour. The SLN location was marked on the skin. All patients underwent standard modified radical mastectomy with axillary lymph node dissection (ALND). A comparison of SLN and ALN histopathological results was completed in order to define the means by which the SLN biopsy was able to reflect the final status of ALNs.

RESULTS

In 20/35 (57.1 percent) cases, SLNs were visualised in 20-minute dynamic imaging. In 12 patients, SLNs were seen after delayed imaging and/or by repositioning the patient. Overall, the estimated SLN identification rate was 91.4 percent. Of 32 patients in whom SLNs were localised by lymphoscintigraphy, nine were positive for metastatic tumours and the rest were negative for tumour involvement. In four of these nine patients, SLN was the only node that contained metastatic tumour cells while in five patients, an additional concomitant ALN metastasis was detected. In four patients, SLN was negative on frozen section, but skip ALN metastases were noted. Of three patients in which SLNs were not localised by lymphoscintigraphy, two had positive ALNs for tumour cells and the remaining one was negative for tumour involvement.

CONCLUSION

We concluded that SLN localisation using lymphoscintigraphy is an accurate minimally-invasive procedure for staging breast cancer patients with clinically-negative ALNs, and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the majority of patients.

Measurement of left ventricular ejection fraction from gated technetium-99m sestamibi myocardial images

Left ventricular ejection fraction (LVEF) and single-photon emission tomographic (SPET) imaging of the myocardium can be performed after a single technetium-99m sestamibi (MIBI) injection. Sixty patients underwent SPET imaging with MIBI. Immediately after SPET acquisition ECG-gated 99mTc-MIBI perfusion images were acquired using 24 planar images per R-R interval. A new method for measurement of LVEF from the ECG-gated 99mTc-MIBI perfusion images was developed. To validate the method, LVEF derived from MIBI perfusion images was compared with that from conventional radionuclide ventriculography in all 60 patients. Forty patients had evidence of myocardial infarction and 20 had normal perfusion on MIBI imaging. There was no statistically significant difference between LVEF computed from 99mTc-MIBI perfusion images and that from radionuclide ventriculography (r = 0.7062, P < 0.001). There was little difference associated with the technique (intraobserver variability r = 0.9772, P < 0.001). Interobserver variability was also good (r = 0.8233, P < 0.001). LVEF from 99mTc-MIBI perfusion images can be obtained at the same time as assessment of myocardial perfusion and in the same orientation and metabolism of the myocardium, thereby permitting more accurate and realistic prognosis and diagnosis in patients with coronary artery disease.