Three-dimensional reconstruction of cervical CT vs ultrasound for estimating residual thyroid volume / 南方医科大学学报

OBJECTIVE@#To compare the accuracy of three-dimensional reconstruction of cervical CT and ultrasound for estimating residual thyroid volume.@*METHODS@#We performed a retrospective analysis of 17 patients with 21 residual thyroid glands undergoing thyroidectomy surgery between February, 2017 and March, 2018 in our department. We compared the residual thyroid volume in preoperative ultrasound with the intraoperative measurement and the volume measured using threedimensional CT reconstruction before surgery.@*RESULTS@#The maximum vertical and anterioposterior diameters of the residual thyroid measured by preoperative ultrasound differed significantly from the volume data measured intraoperatively ( < 0.05), but the difference in the maximum left-right diameters was not statistically significant (>0.05). The maximum vertical, leftright, and anteroposterior diameters estimated by three-dimensional reconstruction of cervical CT was all similar with those measured intraoperatively (>0.05).@*CONCLUSIONS@#Compared with ultrasound examination, three-dimensional reconstruction of neck CT is more accurate for estimating the residual thyroid volume and provides more reliable evidence for clinical calculation of postoperative I dose for thyroid cancer.

Diagnostic whole body scan (pre‑therapy scan) in differentiated thyroid cancer: A single center community hospital experience.

OBJECTIVE: Diagnostic whole body scan (pre‑therapy scan) with either I‑123 or I‑131 (radioactive isotopes of iodine) is performed to assess the extent of thyroid cancer especially distant metastasis prior to administering the therapeutic dose of I‑131. Our aim of the following study was to determine the utility of the diagnostic pre‑therapy scan in the management of differentiated thyroid cancer. MATERIALS AND METHODS: It was a case‑control study carried out by retrospective chart review, of a randomly selected 100 patients with differentiated thyroid cancer who had followed in our community hospital over the course of 1 year. We collected data on multiple variables in the subjects ‑ including age, gender, pre‑operative size of the nodules, diagnosis, stage of the malignancy, size of the tumor, multifocality, lymphovascular invasion, dose of radioiodine used for remnant ablation, recurrence rates and persistence rates. Continuous variables were compared using the independent sample Mann‑Whitney U‑test whereas the Chi‑square test was used for nominal variables. RESULTS: The mean dose of radioactive iodine administered was 97.56 (±27.98) in the pre‑therapy scan group and it was 97.23 (±32.40) in the control group. There was no difference between the two groups (P ‑ 0.45). There was also no difference in the recurrence rates between the groups (P = 1.0). There was a trend toward a higher degree of persistent cancer in the group that had the pre‑therapy scans (P ‑ 0.086). CONCLUSION: Pre‑therapy scan may not affect the dose of radio‑iodine I‑131 used for remnant ablation of differentiated thyroid cancer and does not influence the recurrence rates. This was especially true with respect to I‑131 remnant ablation for low risk tumors.

Therapy dose calculation in Graves disease using 4-hour I-131 uptake measurements: A retrospective study

Twenty-four-hour radioactive iodine uptake (RAIU) is commonly used to compute for therapy dose in Graves disease (GD). The purpose of this study is to determine the feasibility of using 4-hour RAIU in calculating the dose by correlating 4-hour with 24-hour RAIU and comparing the actual therapy dose using 24-hour RAIU with the computed dose using 4-hour RAIU. A total of 83 GD patients (71% female, 29% male;18-50 years old), who underwent RAI therapy at USTH Section of Nuclear Medicine, were included. There was a strong and positive correlation between 4-hour and 24-hour RAIU values (r=0.736). Paired t-test did not show a statistical difference between the actual given therapy dose based on 24-hour RAIU and the computed therapy dose using 4-hour RAIU (p 0.078). This study showed that therapy dose calculation using 4-hour RAIU can be used in Graves disease patients with no rapid turnover.

Analysis of Urine Iodine Excretion Decrease by Two-Week Stringent Low Iodine Diet for Remnant Thyroid Ablation with Radioactive Iodine in Korean Patients with Thyroid Cancer; Prospective Study / 핵의학분자영상

A low iodine diet (LID) is the recommended preparation for radioactive iodine treatment. However, the recommended duration and stringency of LID are different among each recommendation. More stringent LID is expected in Korea because Korea is a iodine-rich region. We investigated the decrement of urine iodine excretion by two-week stringent LID for remnant thyroid ablation with radioactive iodine in Korean patients with thyroid cancer, prospectively. MATERIAL AND METHOD: From November 2006, patients who referred to our hospital for remnant ablation after total thyroidectomy were included in this study. To decrease total body iodine, our protocol included three strategies. First, we checked medication which could inhibit the radioactive iodine uptake. Second, the date of I-131 treatment was scheduled at least 3 months later if contrast agent had been used. The last strategy was two-week stringent LID education by specialized nutritionist. Before and after two-week stringent LID, 24hr-urine iodine was analyzed respectively. 24hr-urine creatinine was also analyzed for determining more valid 24hr urine sampling subgroup. RESULTS: Total 51 patients were finally enrolled. Average of 24hr-urine iodine excretion was significantly lowered (787+/-2242 -> 85+/-85 microgram/d, p=0.03) after LID and 74.4% of patients reached below the recommended urine iodine excretion level ( 99+/-116 microgram/d, p=0.05) and 78.6% of patients met the criteria. CONCLUSION: Most patients could reach below the recommended urine iodine level after two-week stringent LID. Therefore, in our opinion, at least two-week stringent LID should be recommended in Korea.

Comparison of Urine Iodine/Creatinine ratio between Patients following Stringent and Less Stringent Low Iodine Diet for Radioiodine Remnant Ablation of Thyroid Cancer / 핵의학분자영상

A low iodine diet (LID) for 1~2 weeks is recommended for patients who undergoing radioiodine remnant ablation. However, the LID educations for patients are different among centers because there is no concrete recommendation for protocol of LID. In this investigation, we compared two representative types of LID protocols performed in several centers in Korea using urine iodine to creatinine ratio (urine I/Cr). METHODS: From 2006, April to June, patients referred to our center for radioiodine remnant ablation of thyroid cancer from several local hospitals which had different LID protocols were included. We divided into two groups, stringent LID for 1week and less stringent LID for 2 weeks, then measured their urine I/Cr ratio with spot urine when patients were admitted to the hospital. RESULTS: Total 27 patients were included in this investigation (M:F=1:26; 13 in one-week stringent LID; 14 in two-week less stringent LID). Average of urine I/Cr ratio was 127.87+/-78.52 microgram/g in stringent LID for 1 week, and 289.75+/-188.24 microgram/g in less stringent LID for 2 weeks. It was significantly lower in stringent LID for 1 week group (p=0.008). The number of patients whose urine I/Cr ratios were below 100 microgram/g was 6 of 13 in stringent LID for 1 week group, and 3 of 14 in less stringent LID for 2 weeks group. CONCLUSION: Stringent LID for 1 week resulted in better urinary I/Cr ratio in our investigation compared with the other protocol. However it still resulted in plenty of inadequate range of I/Cr ratio, so more stringent protocol such as stringent LID for 2 weeks is expected more desirable.

Development and Assessment Individual Maximum Permissible Dose Method of I-131 Therapy in High Risk Patients with Differentiated Papillary Thyroid Cancer / 대한핵의학회잡지

PURPOSE: Radioiodine (I-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. MATERIALS AND METHODS: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age 50+/-11 years) of papillary thyroid cancer. Among them 43 patients were treated with or =9.25 GBq. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up I-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. RESULTS: MPD measured by CF method using tracer and therapeutic doses were 13.3+/-1.9 and 13.8+/-2.1 GBq, respectively (p=0.20). They showed a significant correlation (r=0.8, p< 0.0001). Exposed doses to blood measured by CF and biological methods were 1.54+/-0.03 and 1.78+/-0.03 Gy (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-dose group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). CONCLUSION: Measurement of MPD using CF method is reliable, and the high-dose I-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.

Low-dose Radioactive I-131 Therapy Following Total Thyroidectomy for Differentiated Thyroid Cancer / 대한내분비외과학회지

PURPOSE: To assess the effectiveness of low-dose (30 mCi) I-131 ablation therapy for remnant thyroid tissue following total thyroidectomy for differentiated thyroid cancer. METHODS: Between March 1995 and December 1997, 48 patients were given ablative doses (30 mCi) of I-131 following total thyroidectomy for differentiated thyroid cancer in the presence of I-131 uptake in remnant thyroid tissue. The effective ablation of remnant thyroid tissue was determined using a subsequent I-131 whole body scan. If any remnant thyroid tissue remained, we repeated the same management protocol at 6-month intervals. RESULTS: Thirty-eight (79.1%) patients displayed papillary, 8 (16.7%) follicular, 1 (2.1%) medullary and 1 (2.1%) Hurthle cell type cancer. Forty-eight patients underwent total thyroidectomy, 35 cases of which underwent central neck dissection, and 14 cases modified radical neck dissection. Postoperative complication developed in 8 cases, including 4 cases of transient hypoparathyroidism, 1 case of permanent hypoparathyroidism, 2 cases of transient recurrent laryngeal nerve palsy, and 1 case of wound hematoma. There was significant remnant thyroid tissue detected in 46 cases (95.8%) following total thyroidectomy, which were able to be ablated by low dose (30 mCi) I-131. There was no statistical difference between the operative procedures or the numbers of treatment of I-131. CONCLUSION: This data suggests that low-dose (30 mCi) I 131 therapy is effective for the ablation of remnant thyroid tissue following total thyroidectomy for differentiated thyroid cancer.

Radiation Adaptive Response Induced by I-131 Therapy in Patients with Differentiated Thyroid Cancer / 대한핵의학회잡지

PURPOSE: The purpose of this study was to ascertain whether radiation adaptive response could be induced by high dose I-131 therapy in patients with differentiated thyroid cancer. MATERIALS AND METHODS: Lymphocytes from 21 patients (7 males, 14 females, mean age 55+/-12 years) were collected before and after administration of 5,550 MBq (150 mCi) I-131. They were exposed to a challenge dose of 1 Gy gamma rays using a Cs-137 cell irradiator. The number of ring-form (R) and dicentric (D) chromosomes was counted under the light microscope, and used to calculate the frequency of chromosomal aberration. Ydr, which was defined as the sum of R and D divided by the total number of counted lymphocytes. RESULTS: Ydr in patients before I-131 therapy (0.09+/-0.01) was not different from that of controls (0.08+/-0.01). Ydr was significantly increased to 0.13+/-0.02 (p<0.0001) after I-131 therapy. Increase of Ydr after the challenge irradiation of 1 Gy was significantly lower in patients after I-131 therapy than before I-131 therapy (0.17+/-0.03 vs 0.21+/-0.02, p<0.0001). Cycloheximide (CHM), an inhibitor of protein synthesis, abolished this effect. Ydr after CHM (0.20+/-0.01) was significantly higher than Ydr after I-131 therapy (0.17+/-0.03, p<0.0001), but was not different from Ydr before I-131 therapy (0.21+/-0.02). CONCLUSION: High dose I-131 therapy induces an adaptive response in peripheral lymphocytes of patients with well-differentiated thyroid cancer, which is associated with protein synthesis.