Breast cancer risk among thyroid cancer survivors and the role of I-131 treatment

BACKGROUND

Female thyroid cancer survivors are more likely to have a higher risk of breast cancer compared to the general population, and the underlying causes are yet to be understood. The potential role of I-131 treatment on this association remains controversial.

METHODS

We pooled individual data of women who were treated for differentiated thyroid cancer from 1934 to 2005 in France, Italy and Sweden. Standardized incidence ratios (SIRs) for breast cancer were estimated by comparison with age, sex and calendar-year expected values of the general population in each country. We estimated breast cancer risk in relation to I-131 treatment using time-dependent Poisson models.

RESULTS

Of 8475 women (mean age at diagnosis: 45 years, range 2-90 years), 335 were diagnosed with breast cancer [SIR = 1.52, 95% confidence interval (CI): 1.36-1.69] during a median follow-up time of 12.7 years since diagnosis. Overall, breast cancer risk did not differ between women treated or not with I-131 (relative risk=1.07, 95% CI 0.84-1.35). However, breast cancer risk increased with increasing cumulative I-131 activity, without significant departure from linearity (excess relative risk per 100 mCi=17%, 95% CI: 2% to 38%). The higher risk associated with a cumulative I-131 activity of ≥100 mCi and ≥400 mCi was translated into 4 (95% CI -4 to 13) and 42 (95% CI -8 to 93) excess breast cancer cases per 10,000 person-years, respectively.

CONCLUSIONS

An elevated risk was observed for the highest cumulative administered activity (>=400 mCi), and a significant dose-dependent association was observed among thyroid cancer survivors who were treated with I-131. However, overall, I-131 treatment might only explain partly the increase in breast cancer risk among female thyroid cancer survivors.

Redifferentiation of a BRAFK601E-Mutated Poorly Differentiated Thyroid Cancer Patient with Dabrafenib and Trametinib Treatment

A 59-year-old woman with locally invasive poorly differentiated thyroid cancer with synchronous lung, mediastinal, and bone metastases and a somatic BRAF^K601E mutation with contraindication for antiangiogenic drugs was treated with dabrafenib and trametinib. During treatment, serum levels of thyroglobulin increased as early as day 7 up to 10-fold over baseline at week 4. Concurrently, clinical hyperthyroidism occurred, with free triiodothyronine and free thyroxine levels increasing to 6.6 and 4.4 times their upper reference limit. Fludeoxyglucose positron emission tomography/computed tomography at one and two months after treatment initiation showed a PERCIST metabolic response with a 82% decrease in fludeoxyglucose uptake, whereas disease remained morphologically stable according to RECIST criteria. A diagnostic radioactive iodine whole-body scan performed when the patient was thyrotoxic with an undetectable serum thyrotropin level, in the absence of any exogenous thyrotropin stimulation, showed high radioactive iodine uptake in the lung, mediastinum, and skull metastases. A biopsy performed two months after treatment initiation showed a more differentiated growth pattern and a decrease in the mitotic activity compared to baseline. An increase of thyroglobulin and thyroid peroxidase was observed at both the protein and mRNA levels. Sodium-iodide symporter mRNA expression increased by >750 times over its initial level, and sodium-iodide symporter protein expression became detectable under treatment. A decrease in general status due to thyrotoxicosis led to treatment discontinuation. Thyrotoxicosis resolved rapidly and radioactive iodine uptake decreased by >90%. This clinical case shows that redifferentiation itself is not necessarily associated with an antitumor effect.

Differential effects of non-dual and focused attention meditations on the formation of automatic perceptual habits in expert practitioners

Non-dual meditation aims to undo maladaptive cognitive and affective patterns by recognizing their constructed and transient nature. We previously found high-amplitude spontaneous gamma (25-40 Hz) oscillatory activity during such practice. Nonetheless, it is unclear how this meditation state differs from other practices, in terms of perceptual information processing. Here, we hypothesized that non-dual meditation can downregulate the automatic formation of perceptual habits. To investigate this hypothesis, we recorded EEG from expert Buddhist meditation practitioners and matched novices to measure two components of the auditory evoked response: the Mismatch Negativity (MMN) and the Late Frontal Negativity (LFN), a potential observed at a latency sensitive to attentional engagement to the auditory environment, during the practices of Open Presence (OP) and Focused Attention (FA), as well as during a control state, in the context of a passive oddball paradigm. We found an increase in gamma oscillatory power during both meditation states in expert practitioners and an interaction between states and groups in the amplitude of the MMN. A further investigation identified the specific interplay between the MMN and the LFN as a possible marker to differentiate the two meditation states as a function of expertise. In experts, the MMN increased during FA, compared to OP, while the opposite pattern was observed at the LFN latency. We propose that the state of OP in experts is characterized by increased sensory monitoring and reduced perceptual inferences compared to FA. This study represents a first attempt to describe the impact of non-dual meditation states on the regulation of automatic brain predictive processes.

[Potential radiation hazard in nuclear medicine]

Nuclear medicine uses unsealed radioisotopes. The potential radiation hazards depend on the amount of radioactivity administered and the type of radionucleide. Thus, radiation safety instructions will minimize radiation exposure and contamination as low as reasonably achievable. National nuclear safety authority requires rules, regulations and exposure limits for both patients and workers. Good practices and training staff contribute to optimize the radioprotection.

Strategies of radioiodine ablation in patients with low-risk thyroid cancer

BACKGROUND

It is not clear whether the administration of radioiodine provides any benefit to patients with low-risk thyroid cancer after a complete surgical resection. The administration of the smallest possible amount of radioiodine would improve care.

METHODS

In our randomized, phase 3 trial, we compared two thyrotropin-stimulation methods (thyroid hormone withdrawal and use of recombinant human thyrotropin) and two radioiodine ((131)I) doses (i.e., administered activities) (1.1 GBq and 3.7 GBq) in a 2-by-2 design. Inclusion criteria were an age of 18 years or older; total thyroidectomy for differentiated thyroid carcinoma; tumor-node-metastasis (TNM) stage, ascertained on pathological examination (p) of a surgical specimen, of pT1 (with tumor diameter ≤1 cm) and N1 or Nx, pT1 (with tumor diameter >1 to 2 cm) and any N stage, or pT2N0; absence of distant metastasis; and no iodine contamination. Thyroid ablation was assessed 8 months after radioiodine administration by neck ultrasonography and measurement of recombinant human thyrotropin-stimulated thyroglobulin. Comparisons were based on an equivalence framework.

RESULTS

There were 752 patients enrolled between 2007 and 2010; 92% had papillary cancer. There were no unexpected serious adverse events. In the 684 patients with data that could be evaluated, ultrasonography of the neck was normal in 652 (95%), and the stimulated thyroglobulin level was 1.0 ng per milliliter or less in 621 of the 652 patients (95%) without detectable thyroglobulin antibodies. Thyroid ablation was complete in 631 of the 684 patients (92%). The ablation rate was equivalent between the (131)I doses and between the thyrotropin-stimulation methods.

CONCLUSIONS

The use of recombinant human thyrotropin and low-dose (1.1 GBq) postoperative radioiodine ablation may be sufficient for the management of low-risk thyroid cancer. (Funded by the French National Cancer Institute [INCa] and the French Ministry of Health; ClinicalTrials.gov number, NCT00435851; INCa number, RECF0447.).

Thyroid cancer patients treated with 131I: radiation dose to relatives after discharge from the hospital

BACKGROUND

Thyroid cancer patients treated with radioiodine are potential source of radiation exposure for other individuals. Thus, we evaluated the radiation dose received by family members of thyroid cancer patients treated with (131)I after hospital discharge.

MATERIALS AND METHODS

Seventy-six family members of 56 thyroid cancer patients were included in the study. Thyroid cancer patients were given 3.7 GBq of (131)I and remained in a radiation protection ward for 3 days. Radiation protection recommendations were given to patients and relatives. Life conditions were recorded and radiation doses were monitored using a personal dosimeter.

RESULTS AND DISCUSSION

At discharge, the mean residual activity was 188 MBq. The mean radiation dose delivered to relatives during the 7 days after discharge was low (51.5 μSv) and was similar with either recombinant human thyrotropin (rhTSH) (59 μSv) or withdrawal (50 μSv) (p = 0.37).

CONCLUSION

With our current practice, radiation doses to relatives are low and well below international recommendations.

Thyroid volume measurement in external beam radiotherapy patients using CT imaging: correlation with clinical and anthropometric characteristics

The aim of this study is to define criteria for accurate representation of the thyroid in human models used to represent external beam radiotherapy (EBRT) patients and evaluate the relationship between the volume of this organ and clinical and anthropometric characteristics. From CT images, we segmented the thyroid gland and calculated its volume for a population of 188 EBRT patients of both sexes, with ages ranging from 1 to 89 years. To evaluate uncertainties linked to measured volumes, experimental studies on the Livermore anthropomorphic phantom were performed. For our population of EBRT patients, we observed that in children, thyroid volume increased rapidly with age, from about 3 cm(3) at 2 years to about 16 cm(3) at 20. In adults, the mean thyroid gland volume was 23.5 ± 9 cm(3) for males and 17.5 ± 8 cm(3) for females. According to anthropometric parameters, the best fit for children was obtained by modeling the log of thyroid volume as a linear function of body surface area (BSA) (p < 0.0001) and age (p = 0.04) and for adults, as a linear function of BSA (p < 0.0001) and gender (p = 0.01). This work enabled us to demonstrate that BSA was the best indicator of thyroid volume for both males and females. These results should be taken into account when modeling the volume of the thyroid in human models used to represent EBRT patients for dosimetry in retrospective studies of the relationship between the estimated dose to the thyroid and long-term follow-up data on EBRT patients.

Health outcomes of children fathered by patients treated with radioiodine for thyroid cancer

CONTEXT AND OBJECTIVES

Radiation is known to be mutagenic. The present study analyses birth outcomes and the health of offspring from men previously exposed to (131) I treatment for thyroid carcinoma.

METHODS

Data on 493 pregnancies (356 from 173 untreated fathers, 23 from 17 patients who have undergone surgery alone and 114 from 63 fathers who received (131) I) were obtained by interviewing male patients treated for thyroid carcinoma who had not received significant external radiation to the testes. Among these pregnancies, 73 were conceived from fathers who had received more than 370 MBq.

RESULTS

The mean activity for the 114 pregnancies fathered by 63 patients was 3993 MBq leading to an estimated radiation dose of 9.2 cGy to the testes (MIRD committee coefficient). No significant differences between untreated and treated fathers were found for any adverse outcome.

CONCLUSION

There was no evidence that exposure to radioiodine affects the outcome of subsequent pregnancies and offspring, whatever the event considered. As our study is underpowered, the question of whether testicular irradiation, fractionated or not, is linked to impaired fertility or consequences on offspring remains to be established.

131I effective half-life and dosimetry in thyroid cancer patients

(131)I treatment in thyroid cancer patients may induce side effects, including extrathyroidal cancer and leukemia. There are still some uncertainties concerning parameters that may influence the effective half-life of (131)I and the absorbed doses by extrathyroidal organs.

METHODS

Whole-body retention of radioiodine was measured in 254 patients, and repeated quantitative whole-body scans and measurements of the urinary excretion of (131)I were performed on 30 of these patients.

RESULTS

The mean effective half-life (10.5 h) was shorter by 31%, with little difference between patients, in the 36 patients who received recombinant human thyroid-stimulating hormone than in the 218 patients who underwent thyroid hormone withdrawal (15.7 h). The residence times in the stomach and in the rest of the body were significantly shorter in patients who received recombinant human thyroid-stimulating hormone than in patients who underwent withdrawal, but the residence times were similar in the colon and bladder.

CONCLUSION

In patients who undergo thyroid hormone withdrawal, the longer mean effective half-life is mainly due to delayed renal excretion of (131)I and results in dose estimates higher than the data in report 53 of the International Commission on Radiological Protection, which were obtained from healthy, euthyroid subjects.

Length and cost of hospital stay of radioiodine ablation in thyroid cancer patients: comparison between preparation with thyroid hormone withdrawal and thyrogen

PURPOSE

Treatment of thyroid cancer consists of thyroidectomy and radioiodine ablation following thyroid-stimulating hormone (TSH) stimulation. Similar ablation rates were obtained with either thyroid hormone withdrawal (THW) or rhTSH. But with rhTSH, the elimination of radioiodine is more rapid, thus reducing its whole-body retention and potentially resulting in a shorter hospital stay. The aim of this study was to assess the financial impact of a reduced length of hospital stay with the use of rhTSH.

METHODS

This was a case-control study of thyroid cancer patients treated postoperatively with 3,700 MBq (100 mCi) radioiodine; 35 patients who received rhTSH were matched with 64 patients submitted to THW according to covariates influencing radioiodine retention. The length of hospitalization (LOH) was estimated for each method according to the threshold of radioiodine retention below which the patient can be discharged from the hospital. The economic analysis was conducted from a hospital perspective. Simulations were performed.

RESULTS

For a threshold of 400 MBq, the LOH was 2.4 days and 3.5 days with rhTSH and THW, respectively, and the cost for an ablation stay was, respectively, 2,146 and 1,807 <euro>. In the French context, 57% of the acquisition cost of rhTSH was compensated by the reduction of the length of hospitalization.

CONCLUSION

By increasing the iodine excretion, rhTSH allows a shorter hospitalization length, which partially compensates its acquisition cost.

Effects of strength training and vascular occlusion

The purpose of our study was to determine if vascular occlusion produced an additive effect on muscle hypertrophy and strength performance with high strength training loads. Sixteen physically active men were divided into two groups: high-intensity (HI = 6 RM) and moderate-intensity training (MI = 12 RM). An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow was reduced during the exercise. The left leg served as a control, thus was trained without vascular occlusion. Knee extension 1 RM and quadriceps cross-sectional area (MRI) were evaluated pre- and post-8 weeks of training. We only found a main time effect for both strength gains and quadriceps hypertrophy (p < 0.001). Therefore, we conclude that vascular occlusion in combination with high-intensity strength training does not augment muscle strength or hypertrophy when compared to high-intensity strength training alone.

Imaging of the distribution of (90)y-ibritumomab tiuxetan in bone marrow and comparison with pathology

PURPOSE

Radioimmunotherapy with anti-CD20 antibodies (Abs) labeled with beta-emitters is now used in the treatment of non-Hodgkin's lymphoma (NHL). Because (90)Y is a pure beta-emitter, no direct image of its distribution can be obtained in humans. In this paper, we present in this study imaging data of (90)Y-Ab distribution in human-mantle-cell lymphoma within a mouse model. Describing the actual distribution of the radionuclide at the level of particles range may have important impact on patient dosimetry and therapy treatment planning.

EXPERIMENTAL DESIGN

NOD/SCID mice were grafted with a human NHL cell line that involves the bone marrow. The mice were treated with (90)Y-ibritumomab tiuxetan (Zevalin); Schering AG, Germany) and sacrificed 2 hours after Zevalin administration. Tissue sections were then prepared and viewed under conventional microscopy. The distribution of the radioactivity in mouse femur was determined by using digital autoradiography and subsequently correlated with immunohistochemical results.

RESULTS

Various extent of bone marrow infiltration was investigated and found to be reproducible. Zevalin uptake was heterogeneous within the bone marrow. However, unspecific mouse monoclonal uptake by accessory myeloid cells gave nonspecific background radioactivity. Treating mice with an irrelevant mouse IgG1 monoclonal antibody (mAb) before Zevalin injection controlled this unspecific uptake, and images were strongly correlated with bone marrow infiltration on histologic analysis.

CONCLUSIONS

Our model was reproducible, and allows for the study of various bone marrow involvement with good sensitivity. We demonstrated that imaging of the beta-emitter was possible with good image quality and that (90)Y-Zevalin is distributed heterogeneously within bone marrow. These data suggest that detailed pharmacokinetics may be developed with this model.

Radiation and inhibition of angiogenesis by canstatin synergize to induce HIF-1alpha-mediated tumor apoptotic switch

Tumor radioresponsiveness depends on endothelial cell death, which leads in turn to tumor hypoxia. Radiation-induced hypoxia was recently shown to trigger tumor radioresistance by activating angiogenesis through hypoxia-inducible factor 1-regulated (HIF-1-regulated) cytokines. We show here that combining targeted radioiodide therapy with angiogenic inhibitors, such as canstatin, enhances direct tumor cell apoptosis, thereby overcoming radio-induced HIF-1-dependent tumor survival pathways in vitro and in vivo. We found that following dual therapy, HIF-1alpha increases the activity of the canstatin-induced alpha(v)beta(5) signaling tumor apoptotic pathway and concomitantly abrogates mitotic checkpoint and tetraploidy triggered by radiation. Apoptosis in conjunction with mitotic catastrophe leads to lethal tumor damage. We discovered that HIF-1 displays a radiosensitizing activity that is highly dependent on treatment modalities by regulating key apoptotic molecular pathways. Our findings therefore support a crucial role for angiogenesis inhibitors in shifting the fate of radiation-induced HIF-1alpha activity from hypoxia-induced tumor radioresistance to hypoxia-induced tumor apoptosis. This study provides a basis for developing new biology-based clinically relevant strategies to improve the efficacy of radiation oncology, using HIF-1 as an ally for cancer therapy.

How the availability of recombinant human TSH has changed the management of patients who have thyroid cancer

Recombinant human TSH (rhTSH) is used in patients who have had surgery for thyroid cancer but are at low risk of recurrence. The rhTSH is used for the preparation of postoperative administration of 3.7 GBq (100 mCi) of radioiodine for thyroid-remnant ablation and for the determination of serum thyroglobulin levels during follow-up. In these two conditions, the efficiencies of levothyroxine withdrawal and rhTSH administration are similar; however, rhTSH can be administered during levothyroxine treatment, and its use avoids the hypothyroid period induced by levothyroxine withdrawal, reduces whole body exposure after radioiodine administration, avoids potential morbidity and maintains a better quality of life compared with hormone withdrawal.

Whole-body distribution and radiation dosimetry of the dopamine transporter radioligand [(11)C]PE2I in healthy volunteers

INTRODUCTION

This study reports on the biodistribution and radiation dosimetry of a cocaine analog, the (E)-N-(3-iodoprop-2-enyl)-2beta-carbomethoxy-3beta-(4'-tolyl)nortropane (PE2I), labeled with carbon 11 ([(11)C]PE2I). [(11)C]PE2I is used in positron emission tomography (PET) for examination of the dopamine neuronal transporter (DAT). DAT radioligands are often used to evaluate the progression of Parkinson's disease or the efficiency of neuroprotective therapeutics, and, typically, these studies required several successive PET scans.

METHODS

In three healthy male volunteers, whole-body scans were performed up to 2 h following intravenous injection of 321+/-6 MBq of [(11)C]PE2I. For each subject, regions of interest were defined over all visible organs to generate time-activity curves and calculate the percentage of injected activity. Time-activity data were fitted to a monoexponential model, as an uptake phase followed by a mono-exponential washout, or bi-exponential model to obtain residence times. With the use of the MIRD method, several source organs were considered in estimating residence time and mean effective radiation absorbed doses.

RESULTS

Blood pressure and ECG findings remained unchanged after radioligand injection. The primary route of clearance was renal. Ten minutes after injection, high activities were observed in the kidneys, urinary-bladder, stomach, liver, salivary glands and brain. The urine bladder wall, stomach and liver received the highest absorbed doses. The average effective dose of [(11)C]PE2I was estimated to be 6.4+/-0.6 microSv/MBq.

CONCLUSION

The amount of [(11)C]PE2I required for adequate DAT PET imaging results in an acceptable effective dose equivalent permitting two or three repeated cerebral PET studies, with the injection of 222 MBq for each study.

Comparison of seven serum thyroglobulin assays in the follow-up of papillary and follicular thyroid cancer patients

BACKGROUND

Serum thyroglobulin (Tg) is the marker of differentiated thyroid cancer after initial treatment and TSH stimulation increases its sensitivity for the diagnosis of recurrent disease.

AIM

The goal of the study is to compare the diagnostic values of seven methods for serum Tg measurement for detecting recurrent disease both during L-T4 treatment and after TSH stimulation.

METHODS

Thyroid cancer patients who had no evidence of persistent disease after initial treatment (total thyroidectomy and radioiodine ablation) were studied at 3 months on L-T4 treatment (Tg1) and then at 9-12 months after withdrawal or recombinant human TSH stimulation (Tg2). Sera with anti-Tg antibodies or with an abnormal recovery test result were excluded from Tg analysis with the corresponding assay. The results of serum Tg determination were compared to the clinical status of the patient at the end of follow-up.

RESULTS

Thirty recurrences were detected among 944 patients. A control 131I total body scan had a low sensitivity, a low specificity, and a low clinical impact. Assuming a common cutoff for all Tg assays at 0.9 ng/ml, sensitivity ranged from 19-40% and 68-76% and specificity ranged from 92-97% and 81-91% for Tg 1 and Tg2, respectively. Using assays with a functional sensitivity at 0.2-0.3 ng/ml, sensitivity was 54-63% and specificity was 89% for Tg1. Using the two methods with a lowest functional sensitivity at 0.02 and 0.11 ng/ml resulted in a higher sensitivity for Tg1 (81% and 78%), but at the expense of a loss of specificity (42% and 63%); finally, for these two methods, using an optimized functional sensitivity according to receiver operating characteristic curves at 0.22 and 0.27 ng/ml resulted in a sensitivity at 65% and specificity at 85-87% for Tg1.

CONCLUSION

Using an assay with a lower functional sensitivity may give an earlier indication of the presence of Tg in the serum on L-T4 treatment and may be used to study the trend in serum Tg without performing any TSH stimulation. Serum Tg determination obtained after TSH stimulation still permits a more reliable assessment of cure and patient's reassurance.

[Image registration for radiation therapy: Practical aspects and quality control]

The development of conformal radiotherapy techniques (CRT) and intensity modulated CRT requires an accurate delineation of target structures and organs at risk. Thus, additional information provided by anatomical and/or functional imaging modalities can be used for volume of interest determination combined with traditionally used Computed Tomography imaging (CT): for instance, functional or morphological Magnetic Resonance Imaging (f MRI or m MRI) or Positron Emission Tomography (PET). A prerequisite to the simultaneous use of this information is image registration. Due to the differences between the images and the information they provide, a quality control of image registration process for radiotherapy is mandatory. The purpose of this article is to present the difficulties in implementing such controls and to show the necessity for a clinical validation on patient's images. The last part of this work presents the possible interest in using f MRI to help radio-oncologists in the treatment planning for gliomas associated to image coregistration and quality control considerations.

Long-term outcome of 444 patients with distant metastases from papillary and follicular thyroid carcinoma: benefits and limits of radioiodine therapy

AIM

The goal of this study was to estimate the cumulative activity of (131)I to be administered to patients with distant metastases from thyroid carcinoma.

METHODS

A total of 444 patients were treated from 1953-1994 for distant metastases from papillary and follicular thyroid carcinoma: 223 had lung metastases only, 115 had bone metastases only, 82 had both lung and bone metastases, and 24 had metastases at other sites. Treatment consisted of the administration of 3.7 GBq (100 mCi) (131)I after withdrawal of thyroid hormone treatment, every 3-9 months during the first 2 yr and then once a year until the disappearance of any metastatic uptake. Thyroxine treatment was given at suppressive doses between (131)I treatment courses.

RESULTS

Negative imaging studies (negative total body (131)I scans and conventional radiographs) were attained in 43% of the 295 patients with (131)I uptake; more frequently in those who were younger, had well-differentiated tumors, and had a limited extent of disease. Most negative studies (96%) were obtained after the administration of 3.7-22 GBq (100-600 mCi). Almost half of negative studies were obtained more than 5 yr after the initiation of the treatment of metastases. Among patients who achieved a negative study, only 7% experienced a subsequent tumor recurrence. Overall survival at 10 yr after initiation of (131)I treatment was 92% in patients who achieved a negative study and 19% in those who did not.

CONCLUSION

(131)I treatment is highly effective in younger patients with (131)I uptake and with small metastases. They should be treated until the disappearance of any uptake or until a cumulative activity of 22 GBq has been administered. In the other patients, other treatment modalities should be used when tumor progression has been documented.

Iodine biokinetics and dosimetry in radioiodine therapy of thyroid cancer: procedures and results of a prospective international controlled study of ablation after rhTSH or hormone withdrawal

Technical aspects and results of the dosimetric assessments of postoperative radioiodine ablation in the framework of an international, prospective, controlled, randomized, comparative study of the effectiveness of ablation therapy with 3.7 GBq (131)I in differentiated thyroid cancer after stimulation with recombinant human TSH (rhTSH) or by thyroid hormone withdrawal (THW) are presented.

METHODS

Sixty-three patients were randomized after thyroidectomy to either the THW or the rhTSH group. Scintigraphic neck images were acquired starting 48 h after radioiodine administration to assess biokinetics in the thyroid remnant. The activity in blood samples was quantified and data from whole-body probe measurements and scintigraphic whole-body scans were combined to deduce retention curves in blood and whole body, respectively. The absorbed dose to the blood was calculated using a modified approach based on the formalism of the MIRD Committee of the Society of Nuclear Medicine.

RESULTS

The effective half-time in the remnant thyroid tissue was significantly longer after rhTSH than THW (67.6 +/- 48.8 vs. 48.0 +/- 52.6 h, respectively; P = 0.01), whereas the observed differences of the mean 48-h (131)I uptakes (0.5% +/- 0.7% vs. 0.9% +/- 1.0% after THW; P = 0.1) and residence times (0.9 +/- 1.3 vs. 1.4 +/- 1.5 h after THW; P = 0.1) between the rhTSH and THW groups were not statistically significant. The specific absorbed dose to the blood was significantly (P <0.0001) lower after administration of rhTSH (mean, 0.109 +/- 0.028 mGy/MBq; maximum, 0.18 mGy/MBq) than after THW (mean, 0.167 +/- 0.061 mGy/MBq; maximum, 0.35 mGy/MBq), indicating that higher activities of radioiodine might be safely administered after exogenous stimulation with rhTSH.

CONCLUSION

Indication of an influence of the residence time of radioiodine in the blood on the fractional uptake into thyroid remnant was found. A novel regimen is proposed in which therapeutic activities to be administered are determined from the individual specific blood dose.

Radioiodine ablation of thyroid remnants after preparation with recombinant human thyrotropin in differentiated thyroid carcinoma: results of an international, randomized, controlled study

CONTEXT

After surgery for differentiated thyroid carcinoma, many patients are treated with radioiodine to ablate remnant thyroid tissue. This procedure has been performed with the patient in the hypothyroid state to promote endogenous TSH stimulation and is often associated with hypothyroid symptoms and impaired quality of life. OBJECTIVE AND INTERVENTION: This international, randomized, controlled, multicenter trial aimed to compare the efficacy and safety of recombinant human TSH (rhTSH) to prepare euthyroid patients on L-thyroxine therapy (euthyroid group) to ablate remnant thyroid tissue with 3.7 GBq (100 mCi) 131I, compared with that with conventional remnant ablation performed in the hypothyroid state (hypothyroid group). Quality of life was determined at the time of randomization and ablation. After the administration of the 131-I dose, the rate of radiation clearance from blood, thyroid remnant, and whole body was measured.

RESULTS

The predefined primary criterion for successful ablation was "no visible uptake in the thyroid bed, or if visible, fractional uptake less than 0.1%" on neck scans performed 8 months after therapy and was satisfied in 100% of patients in both groups. A secondary criterion for ablation, an rhTSH-stimulated serum thyroglobulin concentration less than 2 ng/ml, was fulfilled by 23 of 24 (96%) euthyroid patients and 18 of 21 (86%) hypothyroid patients (P = 0.2341). Quality of life was well preserved in the euthyroid group, compared with the hypothyroid group, as demonstrated by their lower pretreatment scores on the Billewicz scale for hypothyroid signs and symptoms, 27 +/- 7 vs. 18 +/- 4 (P < 0.0001) and their significantly higher Short Form-36 Health Assessment Scale scores in five of eight categories. Euthyroid patients had a statistically significant one third lower radiation dose to the blood, compared with patients in the hypothyroid group.

CONCLUSIONS

This study demonstrates comparable remnant ablation rates in patients prepared for 131I remnant ablation with 3.7 GBq by either administering rhTSH or withholding thyroid hormone. rhTSH-prepared patients maintained a higher quality of life and received less radiation exposure to the blood.

Radiation exposure and familial aggregation of cancers as risk factors for colorectal cancer after radioiodine treatment for thyroid carcinoma

PURPOSE

In thyroid cancer patients, radioiodine treatment has been shown to be associated with an increased risk of colon carcinoma. The aim of this study in thyroid cancer patients was to evaluate the role of familial factors in the risk of colorectal cancer and their potential interaction with radioiodine exposure.

METHODS AND MATERIALS

We performed a case-control study on 15 colorectal cancer patients and 76 matched control subjects, nested in a cohort of 3708 thyroid cancer patients treated between 1933 and 1998. For each patient, the radiation dose delivered to the colon by radioiodine was estimated by use of standard tables. In those who received external radiation therapy, the average radiation doses delivered to the colon and rectum were estimated by use of DOS_Eg software. A complete familial history was obtained by face-to-face interviews, and a familial index was defined to evaluate the degree of familial aggregation.

RESULTS

The risk of colorectal cancer increased with familial aggregation of colorectal cancer (p = 0.02). After adjustment for the radiation dose delivered to the colon and rectum, the risk of colorectal cancer was 2.8-fold higher (95% CI, 1.0-8.0) for patients with at least one relative affected by colorectal cancer than for patients without such a family history (p = 0.05). The radiation dose delivered to the colon and rectum by (131)I and external radiation therapy was associated with an increase of risk near the significance threshold (p = 0.1). No significant interaction was found between radiation dose and having an affected relative (p = 0.9).

CONCLUSIONS

The role of familial background in the risk of colorectal cancer following a differentiated thyroid carcinoma appears to increase with the radiation dose delivered to the colon and rectum. However, the study population was small and no interaction was found between these two factors.

Limb salvage with isolated perfusion for soft tissue sarcoma: could less TNF-α be better?

BACKGROUND

The optimal dose of TNF-alpha delivered by isolated limb perfusion (ILP) in patients with locally advanced soft tissue sarcoma is still unknown.

PATIENTS AND METHODS

Randomised phase II trial comparing hyperthermic ILP (38-40 degrees ) with melphalan and one of the four assigned doses of TNF-alpha: 0.5 mg, 1 mg, 2 mg, and 3/4 mg upper/lower limb. The main end point was objective tumour response on MRI. Secondary end points were histological response, rate of amputation and toxicity. Resection of the remnant tumour was performed 2-3 months after ILP. The sample size was calculated assuming a linear increase of 10% in the objective response rates between each dose level group.

RESULTS

One hundred patients (25 per arm) were included. Thirteen per cent of patients had a systemic leakage with a cardiac toxicity in six patients correlated with high doses of TNF-alpha. Objective tumour responses were: 68%, 56%, 72% and 64% in the 0.5 mg, 1 mg, 2 mg and 3 or 4 mg arms, respectively (NS). Sixteen per cent of patients were not operated, 71% had a conservative surgery and 13% were amputated with no difference between the groups. With a median follow-up of 24 months, the 2 year overall and disease-free survival rates (95% CI) were 82% (73% to 89%) and 49% (39% to 59%), respectively.

CONCLUSION

At the range of TNF-alpha doses tested, there was no dose effect detected for the objective tumour response, but systemic toxicity was significantly correlated with higher TNF-alpha doses. Efficacy and safety of low-dose TNF-alpha could greatly facilitate ILP procedures in the near future.

Biodistribution and radiation dosimetry of [11C]raclopride in healthy volunteers

PURPOSE

This study reports on the whole-body biodistribution and radiation dosimetry of [11C]raclopride, a dopamine D2 receptor antagonist.

METHODS

In three healthy male volunteers, whole-body scans were performed up to 2 h following i.v. injection of 320+/-65 MBq [11C]raclopride. Transmission scans (3 min per step, eight or nine steps according to the height of the subject) in 2D mode were used for subsequent attenuation correction of emission scans. Emission scans (1 min per step, eight or nine steps) were acquired over 2 h. Venous blood samples and urine were collected up to 2 h after injection of the radiotracer. For each subject, the percentage of injected activity measured in regions of interest over brain, intestine, lungs, kidneys and liver was fitted to a mono-exponential model, as an uptake phase followed by a mono-exponential washout, for urinary bladder to generate time-activity curves. Using the MIRD method, several source organs were considered in estimating residence time and mean effective radiation absorbed doses.

RESULTS

Blood pressure and ECG findings remained unchanged after tracer injection. The analysed blood and urine pharmacological parameters did not change significantly after [(11)C]raclopride injection. The primary routes of clearance were renal and intestinal. Ten minutes after injection, high activities were observed in the gall-bladder, kidneys and liver. High activity was observed in the gall-bladder during the whole study. The kidneys, urinary bladder wall, liver and gall-bladder received the highest absorbed doses. The average effective dose of [11C]raclopride was estimated to be 6.7+/-0.4 microSv/MBq.

CONCLUSION

The amount of [11C]raclopride required for adequate dopamine D2 receptor imaging results in an acceptable effective dose equivalent, permitting two or three repeated clinical PET imaging studies, with the injection of 222 MBq for each study.

Age-dependent variation of follicular size and expression of iodine transporters in human thyroid tissue

The high sensitivity of the thyroid gland to the carcinogenic effects of radiation during childhood contrasts with the absence of demonstrable carcinogenic effects of radiation in adults. To better understand these age-related variations, we studied follicular morphometry, functional status, and proliferative activity in 31 thyroid glands removed from relatives of medullary thyroid carcinoma patients, with ages ranging from 3 to 39 y.

METHODS

The mean follicular diameter (MFD) was estimated, and immunohistochemistry was performed with antibodies directed to molecules involved in iodide transport (Na(+)/I(-) symporter [NIS], pendrin, and apical iodide transporter), in organification (thyroperoxidase [TPO] and Duox), in cell cycle and growth (Ki-67, cyclin A and D1, and galectin-3), and in angiogenesis (vascular endothelial growth factor and nitric oxide synthase III [NOSIII]).

RESULTS

Compared with older patients, patients who were < or =12 y old had a smaller MFD (P < 0.001) and more frequently positive NIS, pendrin, and Duox (P < 0.01). Proliferation rate as indicated by cyclin A expression was also higher in patients < 12 y (P < 0.01) but peaked at the time of puberty. Staining for NIS, pendrin, TPO, Duox, and NOSIII was stronger in thyroid glands with a smaller MFD (P < 0.001). On multiple tests adjusted for age and thyroid mass, TPO, Duox, and NOSIII remained significantly correlated to MFD (P < 0.001), whereas staining for NIS and pendrin did not. This finding suggests that NIS and pendrin expression is related mainly to the age of the patient.

CONCLUSION

Smaller follicles with a higher expression of proteins involved in iodide metabolism were found in younger children. In cases of radioiodine contamination in children, the result will be a higher radioactive concentration and, hence, higher radiation doses. This event may induce the development of thyroid cancer under conditions of accelerated proliferation, as evidenced at puberty.

Validation of the EGS usercode DOSE3D for internal beta dose calculation at the cellular and tissue levels

Internal radiotherapy is currently focusing on beta emitters such as 90Y or 131I because of their high-energy emissions. However, conventional dosimetric methods (MIRD) are known to be limited for such applications. They are unable to take into account microscopic radionuclide distribution because standardized anthropomorphic phantoms are used, and absorbed dose is calculated at the organ level. New tools are therefore required for dose assessment at cellular and tissue level (10-100 microm). The purpose of this study was to validate, at this scale, a Monte Carlo usercode (DOSE3D), based on the MORSE combinatorial geometry package and the EGS code system. Dose point-kernel calculations in water were compared to those published by Cross et al and Simpkin and Mackie. They confirm that DOSE3D is a reliable tool for cellular dosimetry in various geometric configurations.

Optimizing the use of LiF:Mg,Cu,P (GR-200 P) to measure low dose irradiation in nuclear medicine

We undertook a study in order to determine the optimal conditions under which thermoluminescent powder LiF:Mg,Cu,P (GR-200 P) could be used for applications in nuclear medicine and for dosimetric needs. First, we defined the conditions chiefly related to the readout chain, namely the optimal mass of GR-200 material used for each readout, which is between 15 and 30 mg, and the optimal glow curve readout, which corresponds to heating in two phases: a rise in temperature at the rate of 10 degrees C s(-1) up to 150 degrees C followed by a plateau lasting 10 s and then another rise in temperature at the rate of 25 degrees C s(-1) up to 260 degrees C followed by a second plateau lasting 6 s. The optimum conditions for using TL material were also studied: using GR-200 P without annealing and performing two successive readouts of the same sample only led to a 0.1% loss in sensitivity per re-use cycle, and the good reproducibility of measurements was preserved with stable and weak residual TL signal. The response of the sample irradiated at three different dose levels with a 60Co gamma photon beam remained constant over 40 d. Sensitivity was preserved to within +/-4% between a few tenths of a microGy and 1 Gy. Our observations concur with the results of the literature and show how to optimize the conditions for using the GR-200 thermoluminescent dosimeter to measure low doses with a simple procedure that preserves the sensitivity of material.

Biodistribution and radiation dosimetry of 18F-fluoro-A-85380 in healthy volunteers

This study reports on the biodistribution and radiation dosimetry of 2-(18)F-Fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine ((18)F-fluoro-A-85380), a promising radioligand for the imaging of central nicotinic acetylcholine receptors (nAChRs).

METHODS

Whole-body scans were performed in 3 healthy male volunteers up to 2 h after intravenous injection of 137-238 MBq (18)F-fluoro-A-85380. Transmission scans (3 min per step, 8 or 9 steps according to the height of the subject) in 2-dimensional mode were used for subsequent correction of attenuation of emission scans. Emission scans (1 min per step) were acquired over 2 h. Venous blood samples were taken up to 2 h after injection of the radiotracer. Urine was freely collected up to 2 h after injection of the radiotracer. For each subject, the percentage of injected activity measured in regions of interest over brain, intestine, stomach, bladder, kidneys, and liver were fitted to a monoexponential model, as an uptake phase followed by a monoexponential washout, or to a biexponential model to generate time-activity curves. Using the MIRD method, ten source organs were considered in estimating radiation absorbed doses for organs of the body.

RESULTS

Injection of (18)F-fluoro-A-85380 was clinically well tolerated and blood and urine pharmacologic parameters did not change significantly. The primary routes of clearance were renal and intestinal. Ten minutes after injection, high activities were observed in the bladder, kidneys, and liver. Slow uptake was seen in the brain. The liver received the highest absorbed dose. The average effective dose of (18)F-fluoro-A-85380 was estimated to be 0.0194 mSv/MBq.

CONCLUSION

The amount of (18)F-fluoro-A-85380 required for adequate nAChR imaging results in an acceptable effective dose equivalent to the patient.

[Significance of sentinel lymph node biopsy in Merkel cell carcinoma. Analysis of 11 cases]

BACKGROUND

Merkel cell carcinoma is an aggressive cutaneous neoplasm with a high propensity for nodal metastases. Regional lymph node involvement develops in 45 to 65 p. 100 of patients. We evaluated in Merkel cell carcinoma the use of sentinel lymph node biopsy which allows the identification of occult nodal metastases.

PATIENTS AND METHODS

Eleven patients diagnosed with Merkel cell carcinoma without clinical nodal involvement underwent pre-operative lymphoscintigraphy followed by sentinel lymphadenectomy with histologic analysis. Identification of microscopic nodal metastases led to complete lymph node dissection and adjuvant radiation therapy to the lymph node basin.

RESULTS

The sentinel lymph node was successfully identified in 9 patients. Two patients demonstrated metastatic disease in their sentinel lymph nodes. At subsequent complete node dissection, one of two patients had an additional metastatic lymph node. None of the eleven patients experienced recurrent disease at a follow-up varying from 1 to 42 months. One patient with a negative sentinel lymph node experienced lymphoedema.

COMMENTS

Our results are consistent with the 14 published studies which totalled 93 patients with Merkel cell carcinoma and identified 29 patients (30 p. 100) with nodal involvement. Metastatic disease was identified only after immunohistochemical analysis in 20 p. 100 of these patients (n=6). Lymph node involvement appears to be a bad prognostic factor with 29.6 p. 100 of disease recurrence, as opposed to 3 p. 100 in patients with an uninvolved sentinel lymph node. Although the prognostic significance of this technique seems interesting, there is no optimal therapeutic approach to sentinel lymph node involvement.

A hand-held imaging probe for radio-guided surgery: physical performance and preliminary clinical experience

Improvements in the specificity of radiopharmaceutical compounds have been paralleled by an upsurge of interest in developing small detectors to assist surgeons in localizing tumour tissue during surgery. This study reports the main technical features and physical characteristics of a new hand-held gamma camera dedicated to accurate and real-time intra-operative imaging. First clinical experience is also reported. The POCI (Per-operative Compact Imager) camera consists of a head module composed of a high-resolution interchangeable lead collimator and a CsI(Na) crystal plate optically coupled to an intensified position-sensitive diode. The current prototype has a 40-mm diameter field of view, an outer diameter of 9.5 cm, a length of 9 cm and a weight of 1.2 kg. Overall detector imaging characteristics were evaluated by technetium-99m phantom measurements. Three patients with breast cancer previously scheduled to undergo sentinel lymph node detection were selected for the preliminary clinical experience. Preoperative images of the lymphatic basin obtained using the POCI camera were compared with conventional transcutaneous explorations using a non-imaging gamma probe. The full-width at half-maximum (FWHM) spatial resolution was investigated in both air and scattering medium; when the phantom was placed in contact with the collimator, the POCI camera exhibited a 3.2 mm FWHM. The corresponding sensitivity was 290 cps/MBq. The preliminary clinical results showed that POCI was able to predict the number and location of all SLNs. In one case, two deep radioactive nodes missed by the gamma probe were detected on the intra-operative images. This very initial experience demonstrates that the physical performance of the POCI camera is adequate for radio-guided surgery. These results are sufficiently encouraging to prompt further evaluation studies designed to determine the specific and optimal clinical role of intra-operative imaging devices.

Radioiodine therapy for papillary and follicular thyroid carcinoma

Radioiodine ((131)I) therapy is used in patients with papillary and follicular thyroid carcinoma for ablation of thyroid remnants and for treatment of persistent or recurrent disease. It should be used selectively, i.e. only in those patients for whom a clinical benefit may be expected.

Relationship between tumor burden and serum thyroglobulin level in patients with papillary and follicular thyroid carcinoma

Serum thyroglobulin (Tg) is a reliable marker for detecting recurrent and persistent disease during the follow-up of patients with papillary and follicular thyroid carcinoma. The goal of this study was to assess the relationship between the serum Tg level measured after thyroid hormone withdrawal and the tumor mass in thyroid cancer patients who underwent surgery with the use of an intraoperative probe for lymph node metastases with (131)I uptake. Patients were classified into one of three groups according to the Tg level: undetectable (n = 18); 1-10 ng/mL (n = 21); and greater than 10 ng/mL (n = 33). The main clinical characteristics and the extent of the disease at the time of initial treatment were similar in these three groups. Lymph node metastases were found in 13 of the 18 patients with undetectable Tg level. Eight patients had persistent foci of uptake after surgery that were located behind the sterno-clavicular joint in six patients. The number of metastatic lymph nodes and their total surface (in mm(2)) or their total volume (in mm(3)) were significantly linked with serum Tg/thyrotropin [TSH] level (p = 0.002 and p < 0.0001, respectively). For a given metastatic surface or volume, the serum Tg/TSH value was no longer linked with the number of metastatic lymph nodes (p = 0.32), suggesting that the total surface or total volume is the characteristic that best summarizes the influence of the disease on the serum Tg/TSH level. In conclusion, patients with higher serum Tg levels tend to have more extensive disease and should undergo more aggressive treatment modalities. Nevertheless, undetectable serum Tg should not be considered as a reliable criteria to exclude a minimal tumor burden in patients who have already been treated with (131)I.

Evaluation of physical performance of a scintillation dosemeter for patient dosimetry in diagnostic radiology

The physical performance of the patient scintillation dosemeter Skin Dose Monitor (SDM) was evaluated for use in diagnostic radiology. The SDM response was found to be linear, with output air kerma and output air kerma rate having a reproducibility in time lower than +/- 2.4%) (one standard deviation). A calibration protocol taking into account the more significant parameters, such as radiation quality dependence and the relative sensitivity of SDM detectors of the same batch, can be applied so that the maximum overall uncertainty is +/- 18% at the 95% confidence level. The SDM detectors did not show any loss of sensitivity during the 5-month period of evaluation. SDM performance was evaluated against thermoluminescent dosemeters (TLDs) (GR200A) by monitoring chest X-rays in 18 adult patients. The difference in entrance surface dose (ESD) values between the SDM and TLDs was less than 10%, but a lack of accuracy in ESD values of less than 0.3 mGy was observed. The main benefit of the SDM device compared with TLDs is the real-time read-out of dose combined with a better flexibility and rapidity of use for approximately the same cost per measurement. The SDM device is a good candidate for regular measurement of patient doses in diagnostic imaging departments as required under implementation of the European Council Medical Exposure Directive of 30 June 1997.

Clinical use of recombinant human TSH in thyroid cancer patients

Recombinant human TSH (rhTSH) is an effective and safe alternative to thyroid hormone withdrawal during the post-surgical follow-up of papillary and follicular thyroid cancer. Its clinical efficiency for the detection of persistent and recurrent disease is similar to that of thyroid hormone withdrawal. The main purpose for its use is to avoid hypothyroidism.

Improvement of internal dose calculations using mathematical models of different adult heights

In internal dosimetry for both nuclear medicine and radiation protection, the adult morphology is represented by a limited number of anthropomorphic models that may not be suitable for all patients. To develop more patient-specific dosimetry, we derived six mathematical models for adults of different height. Three male models (160 cm, 170 cm and 180 cm) and three female models (150 cm, 160 cm and 170 cm), based on the MIRD model design, were developed from the statistical analysis of anthropometric data gathered from autopsies. Monte Carlo calculations were used to provide an example of estimations of S value for these new models for iodine 131 uniformly distributed successively in the stomach or in the urinary bladder. On average, for both male and female models, an increase in the model height of 10 cm leads to a mean reduction in the S value for iodine-131 by 20% and 29% when the stomach and the urinary bladder respectively are selected as source regions. Similarly, when the model height increases by 20 cm, the S values decrease on average by 35% and 48%. This study presents the use of anthropometric data to develop new mathematical models for adults of different height, and shows the significant influence of the morphology on dosimetric parameters.

Adenovirus-mediated transfer of the thyroid sodium/iodide symporter gene into tumors for a targeted radiotherapy

The Na+/I- symporter (NIS) present in the membranes of thyroid cells is responsible for the capacity of the thyroid to concentrate iodide. This allows treatment of thyroid cancers with 131I. We propose to enlarge this therapeutic strategy to nonthyroid tumors by using an adenoviral vector to deliver the NIS gene into the tumor cells. We constructed a recombinant adenovirus encoding the rat NIS gene under the control of the cytomegalovirus promoter (AdNIS). Infection of SiHa cells (human cervix tumor cells) with AdNIS resulted in perchlorate-sensitive 125I uptake by these cells to a level 125-225 times higher than that in noninfected cells. Similar results were obtained for other human tumor cell lines, including MCF7 and T-47D (mammary gland), DU 145 and PC-3 (prostate), A549 (lung), and HT-29 (colon), demonstrating that the AdNIS vector can function in tumor cells of various origins. In addition, AdNIS-infected tumor cells were selectively killed by exposure to 131I, as revealed by clonogenic assays. To assess the efficiency of this cancer gene therapy strategy in vivo, we injected the AdNIS vector in human tumors (SiHa or MCF7 cells) established s.c. in nude mice. Immunohistological analysis confirmed the expression of the NIS protein in the tumor. Three days after intratumoral injection, AdNIS-treated tumors could specifically accumulate 125I or 123I, as revealed by kinetics and imaging experiments. A quantitative analysis demonstrated that the uptake in AdNIS-injected tumors was 4-25 times higher than that in nontreated tumors. On average, 11% of the total amount of injected 125I could be recovered per gram of AdNIS-treated tumor tissue. Altogether, these data indicate that AdNIS is very efficient in triggering significant iodide uptake by a tumor, outlining the potential of this novel cancer gene therapy approach for a targeted radiotherapy.

Pectinase in papermaking: solving retention problems in mechanical pulps bleached with hydrogen peroxide

Treatment with the enzyme pectinase has been reported to lower the cationic demand of thermomechanical pulp (TMP) bleached with alkaline peroxide in the laboratory. We have extended this discovery to bleached TMP produced industrially, and shown that commercial enzyme preparations can treat pulp within 15 min at the temperature and pH values prevalent in paper mills. About half of the cationic demand in the bleached pulp can be destroyed by pectinase. Dynamic drainage jar experiments show that the enzyme treatment improves the effectiveness of several cationic polymers to increase retention of fines and filler particles. It does not increase retention in the absence of retention aids or with nonionic polymers, and does not damage the strength properties of the pulp. Pectinase could be easily incorporated into paper machine stock preparation systems to lower the charges of cationic retention aids needed in furnishes containing peroxide-bleached mechanical pulp.

Is diagnostic iodine-131 scanning useful after total thyroid ablation for differentiated thyroid cancer?

A diagnostic iodine-131 (131I) total body scan (TBS) is usually recommended 6 to 12 months after thyroid ablation for differentiated thyroid carcinoma. Its usefulness was evaluated in 256 consecutive patients treated and followed up at the Institut Gustave Roussy for papillary (n = 200), well differentiated (n = 27), or poorly differentiated (n = 29) follicular thyroid carcinomas. All patients underwent a near-total or total thyroidectomy and 131I ablation with 3.7 GBq (100 mCi). No TBS was performed before 131I ablation. The TBS performed after the administration of 131I to destroy the thyroid remnants showed uptake (<2%) limited to the thyroid bed. A diagnostic 131I-TBS was obtained after withdrawal of T4 treatment, with either 74 MBq (2 mCi; n = 82) or 185 MBq (5 mCi; n = 174), 6 to 12 months after initial treatment, with serum thyroglobulin (Tg) determination. No interference in the Tg assay was found in these 256 patients. Uptake in the thyroid bed was not detected (total ablation) in 236 patients, was visible but too low to be measured in 19 patients, and attained 1% in only 1 patient. No uptake was found outside the thyroid bed. The serum Tg level, once thyroid hormone treatment had been withdrawn, was below 1 ng/mL in 210 patients, ranged from 1-10 ng/mL in 31 patients, and was above 10 ng/mL in 15 patients. A 131I-TBS performed with 3.7 GBq in nine patients with a Tg level above 10 ng/mL, showed foci of uptake outside the thyroid bed in three patients; lung metastases were demonstrated by a CT scan in another patient, and palpable lymph node metastases were found in one patient. In conclusion, a diagnostic 131I-TBS with 74-185 MBq performed 1 yr after thyroid ablation demonstrated no abnormal uptake; it did not correlate with results of Tg determination and only confirmed the completeness of thyroid ablation. The serum Tg level obtained after withdrawal of T4 treatment permits the selection of patients with a Tg level exceeding 10 ng/mL, for scanning with 3.7 GBq (100 mCi).

Serum dexamethasone levels after decadron phonophoresis

OBJECTIVE

To determine serum levels of dexamethasone at several intervals after administration of Decadron (dexamethasone sodium phosphate) phonophoresis.

DESIGN AND SETTING

This study was designed as a 2-factor analysis of variance with repeated measures on 1 factor (blood draws). Independent variables were group (gel/sham, gel/ ultrasound, dexamethasone/sham, dexamethasone/ultrasound) and blood draws (pretreatment, posttreatment, 15 minutes, and 30 minutes). The dependent variable was the serum level of dexamethasone.

SUBJECTS

Forty healthy college students (21 males, 19 females; mean age = 22 +/- 1.3 years) with no known drug allergies or current medication use were randomly assigned to 1 of 4 treatment groups. The treatment site was the left forearm.

MEASUREMENTS

After the pretreatment blood draw, a 10- minute ultrasound treatment was administered, followed by a posttreatment blood draw. Two additional blood draws followed at 15-minute intervals. A total of 4 serum samples (5 cc each) from each subject were centrifuged, and the pipetted serum was frozen for later analysis by double antibody radioimmunoassay.

RESULTS

No significant amounts of serum dexamethasone were detected in 12 consecutive samples. Testing of additional samples was, therefore, discontinued.

CONCLUSIONS

Decadron phonophoresis as used in this experiment did not result in detectable serum levels of dexamethasone. More study is needed to validate the efficacy of Decadron phonophoresis on serum dexamethasone levels.

Personal pronouns and perspective taking in toddlers

This study examined the evolution of visual perspective-taking skills in relation to the comprehension and production of first, second and third person pronouns. Twelve French-speaking and 12 English-speaking children were observed longitudinally from 1.6 until they had acquired all pronouns and succeeded on all tasks. Free-play sessions and three tasks were used to test pronominal competence. Four other tasks assessed Level-1 perspective-taking skills: two of these tasks required the capacity to consider two visual perspectives, and two others tested the capacity to coordinate three such perspectives. The results indicated that children's performance on perspective-taking tasks was correlated with full pronoun acquisition. Moreover, competence at coordinating two visual perspectives preceded the full mastery of first and second person pronouns, and competence at coordinating three perspectives preceded the full mastery of third person pronouns when a strict criterion was adopted. However, with less stringent criteria, the sequence from perspective taking to pronoun acquisition varied either slightly or considerably. These findings are discussed in the light of the 'specificity hypothesis' concerning the links between cognition and language, and also in the context of the recent body of research on the child's developing theory of mind.

DOSE3D: EGS4 Monte Carlo code-based software for internal radionuclide dosimetry

MIRDOSE3 software is currently the main tool available in clinical practice to evaluate absorbed dose in nuclear medicine. Because MIRDOSE3 provides dosimetric parameters for specific anatomic models that cannot be modified by the user, it cannot be used to obtain information concerning metastases or to consider patients whose anatomy differs significantly from that of the standard models.

METHODS

To address some of these inconveniences, we developed an original program based on the EGS4 Monte Carlo code, DOSE3D, which calculates dosimetric parameters for anthropomorphic phantoms defined with combinatorial geometry. DOSE3D allows the user to add spheres within the phantom for simulating tumors, to change the shape of one or more organs and, for organs defined by pair, to calculate individual dosimetric parameters for each organ. The program was validated for 131I and 99mTc by calculating S values for the Medical Internal Radiation Dose (MIRD) adult male phantom and comparing these results with data provided by MIRDOSE3. Moreover, two studies were performed to illustrate DOSE3D features. The first one concerned the evaluation of the individual influence of two bone metastases (located in the pelvis and in the lower spine and containing 131I) on testes in terms of S values compared with the influence on testes of other source organs (kidneys, liver, lungs, spleen, thyroid gland and urinary bladder contents). The second study determined the differences of S values between right and left lungs and right and left kidneys when 131I is contained in the liver.

RESULTS

The DOSE3D S values were on average within 20% of the MIRDOSE3 results for both radionuclides. Regarding the bone metastases study, S(testes<--metastases) and S(testes<--any source organs) were of the same order of magnitude. In the second study, the S values ratio between right and left organs was 7.7 for the lungs and 5.2 for the kidneys.

CONCLUSION

The agreement between DOSE3D and MIRDOSE3 results for most organs shows the validity of DOSE3D. The presented examples of calculation show that DOSE3D could provide additional data to dosimetric parameters given by MIRDOSE3 for a more patient-specific dosimetric approach.