La estimulación previa con rhTSH mejora la respuesta al tratamiento con radioyodo en pacientes con bocio multinodular tóxico de baja captación / Recombinant human thyrotropin stimulation prior to 131I therapy in toxic multinodular goitre with low radioactive iodine uptake

Introducción. La estimulación con TSH recombinante humana (rhTSH) aumenta la captación tiroidea de yodo, ayudando al tratamiento con radioyodo en el bocio multinodular (BMN) no tóxico. Sin embargo, son escasos los estudios que utilicen rhTSH previo a terapia con radioyodo en el BMN tóxico para controlar la hiperfunción y clínica compresiva. Material y método. Se llevó a cabo un estudio prospectivo en pacientes con BMN e hipertiroidismo. Los pacientes se reclutaron de forma consecutiva y se dividieron en un grupo I, estimulados con 0,3mg de rhTSH antes de recibir radioyodo, y un grupo control o grupo II, sin estimulación previa. Se midió función tiroidea, captación tiroidea de radioyodo, peso tiroideo y síntomas compresivos, y se siguió a los pacientes durante 9 meses. Resultados. Un total de 16 pacientes (14 mujeres) de edad media 69,7años constituyeron el grupo I y 16 pacientes (12 mujeres) de edad media 70,7años, el grupo II. Tras el estímulo con 0,3mg rhTSH en el grupo I, la captación de 131I a las 24h aumentó un 78,4% y la dosis estimada absorbida, un 89,3%. En el grupo II, la dosis estimada absorbida fue inferior a la del grupo I tras la estimulación con rhTSH (29,8Gy vs. 56,4Gy; p=0,001). A los 9 meses, se había controlado el hipertiroidismo en un 87,5% de pacientes en el grupo I, y en un 56,2% en el grupo II (p=0,049). La reducción media de peso tiroideo fue mayor en el grupo I que en el II (39,3% vs. 26,9%; p=0,017), con una tendencia a la mejoría subjetiva de la clínica compresiva en el grupo I, aunque no significativa. Solo 2 pacientes describieron taquicardias tras la administración de rhTSH, que se resolvieron con beta-bloqueantes. Conclusiones. La estimulación con rhTSH a dosis de 0,3mg previa al tratamiento con radioyodo consigue una reducción del tamaño tiroideo y mejoría funcional en pacientes con hipertiroidismo y BMN de baja captación, sin necesidad de ingreso hospitalario (AU)

Aim. Stimulation with recombinant human thyrotropin (rhTSH) increases thyroid radioiodine uptake, and is an aid to 131I therapy in non-toxic multinodular goitre (MNG). However, there are not many studies using rhTSH prior to 131I in toxic multinodular goitre to improve hyperthyroidism and compressive symptoms. Material and method. A prospective study was conducted on patients with MNG and hyperthyroidism. Patients were recruited consecutively and divided into group I, stimulated with 0.3mg of rhTSH before radioiodine therapy, and a control group or group II, without stimulation. Thyroid function, radioiodine thyroid uptake, thyroid weight, and compressive symptoms were measured, and patients were followed-up for 9 months. Results. Group I consisted of 16 patients (14 women), with a mean age 69.7 years, and group II with 16 patients (12 women), with a mean age 70.7 years. After stimulation with 0.3mg rhTSH in group I, 131I uptake (RAIU) at 24h increased by 78.4%, and the estimated absorbed dose by 89.3%. In group II, the estimated absorbed dose was lower than group I after stimulation with rhTSH (29.8Gy vs. 56.4Gy; P=0.001). At 9 months of follow-up, hyperthyroidism was controlled in 87.5% of patients in group I, and 56.2% in group II (P=0.049). The mean reduction in thyroid weight was higher in group I than in group II (39.3% vs. 26.9%; P=0.017), with a tendency towards subjective improvement of compressive symptoms in group I, although non-significant. Only 2 patients described tachycardias after rhTSH administration, which were resolved with beta-blockers. Conclusion. Stimulation with 0.3mg of recombinant human thyrotropin prior to radioiodine therapy achieves a reduction in thyroid weight and functional improvement in patients with hyperthyroidism and multinodular goitre with low uptake, and with no need for hospital admission (AU)

[Ultrastructural study on the facial nerve of rabbit after (125)I seed implantation].

OBJECTIVE: To investigate the ultrastructural variation of the facial nerve of rabbit with different dosage of (125)I seed brachytherapy. METHODS: Fifty-four big ear rabbits were divided into 3 groups randomly and given 40 Gy, 80 Gy, 120 Gy respectively. Radioactive seeds were implanted in one side of parotid gland, the other side was implanted with vacant shell as a control group. The facial nerves were obtained 2, 4, 6 months respectively after operation and the histological ultrastructural changes observed by electromicroscope. RESULTS: In the control group, epineurium was continuous, there was slight pitting edema under the epineurium, and axonal myelin was loose. In the test groups, there was slight pitting edema under the epineurium, and axonal myelin sheath was loose at 4th month. Macrophage and regenerated fibers were found in the 80 Gy group and myelin sheath lamellar separation, regeneration of nerve in the 120 Gy dosage. The myelin sheath lamellar was separated and axonal myelin loose in the test group at 6th month. Myelin sheath amellar separation and edema under the epineurium were found in the group of 80 Gy and 120 Gy. CONCLUSIONS: The ultrastructure of the facial nerve is damaged by the dosage of 40 Gy, 80 Gy brachytherapy with (125)I seeds. The higher dosage the nerve receives, the more serious the damage will be. Both of the epineurium and axonal myelin sheath are integral and continuous 6 months after operation with dosage of 120 Gy.

Evaluation of excitation functions of proton and deuteron induced reactions on enriched tellurium isotopes with special relevance to the production of iodine-124.

Cross-section data for the production of medically important radionuclide (124)I via five proton and deuteron induced reactions on enriched tellurium isotopes were evaluated. The nuclear model codes, STAPRE, EMPIRE and TALYS, were used for consistency checks of the experimental data. Recommended excitation functions were derived using a well-defined statistical procedure. Therefrom integral yields were calculated. The various production routes of (124)I were compared. Presently the (124)Te(p,n)(124)I reaction is the method of choice; however, the (125)Te(p,2n)(124)I reaction also appears to have great potential.

Evaluation of irradiation parameters of enriched 124Xe target for 123I production in cyclotrons.

The production of high-purity (123)I that utilizes an isotopically enriched (124)Xe target and bombardment with 30 MeV protons, through the reactions (124)Xe (p, 2n) (123)Cs-->(123)Xe-->(123)I and (124)Xe (p, pn) (123)Xe-->(123)I, is described. The aim of this work was to improve the production parameters, such as (124)Xe load pressure, beam current, decay time and target heating to recover (123)I to obtain high-production (123)I yield at low cost.

A comparison of acute and chronic toxicity for men with low-risk prostate cancer treated with intensity-modulated radiation therapy or (125)I permanent implant.

PURPOSE: To compare the toxicity and biochemical outcomes of intensity-modulated radiation therapy (IMRT) and (125)I transperineal permanent prostate seed implant ((125)I) for patients with low-risk prostate cancer. METHODS AND MATERIALS: Between 1998 and 2004, a total of 374 low-risk patients (prostate-specific antigen < 10 ng/ml, T1c-T2b, Gleason score of 6 or less, and no neoadjuvant hormones) were treated at Fox Chase Cancer Center (216 IMRT and 158 (125)I patients). Median follow-up was 43 months for IMRT and 48 months for (125)I. The IMRT prescription dose ranged from 74-78 Gy, and (125)I prescription was 145 Gy. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity was recorded by using a modified Radiation Therapy Oncology Group scale. Freedom from biochemical failure was defined by using the Phoenix definition (prostate-specific antigen nadir + 2.0 ng/ml). RESULTS: Patients treated by using IMRT were more likely to be older and have a higher baseline American Urological Association symptom index score, history of previous transurethral resection of the prostate, and larger prostate volumes. On multivariate analysis, IMRT was an independent predictor of lower acute and late Grade 2 or higher GU toxicity and late Grade 2 or higher GI toxicity. Three-year actuarial estimates of late Grade 2 or higher toxicity were 2.4% for GI and 3.5% for GU by using IMRT compared with 7.7% for GI and 19.2% for GU for (125)I, respectively. Four-year actuarial estimates of freedom from biochemical failure were 99.5% for IMRT and 93.5% for (125)I (p = 0.09). CONCLUSIONS: The IMRT and (125)I produce similar outcomes, although IMRT appears to have less acute and late toxicity.

[Total prostatectomy--a good option for residual prostate carcinoma after I-125 implantation of external radiotherapy]. / Totale prostatectomie goede mogelijkheid bij residueel prostaatcarcinoom na jodium-125-behandeling of uitwendige radiotherapie.

OBJECTIVE: To evaluate the results of salvage prostatectomy after previous radiation therapy for locally confined prostate cancer. DESIGN: Retrospective. METHOD: Data were collected from the records of all patients with prostate cancer who underwent salvage prostatectomy after I-125 implantation or external radiation therapy in the Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands, 1991-1997. Indications for surgery were: locally confined histologically proven residual cancer, good life expectancy, fit for surgery. Standard preoperative workup was done together with a tumour marker measurement, transrectal ultrasound with biopsy of the prostate and a bonescan. Per- an postoperative complications, pathology result and postoperative PSA were assessed. Progression free survival, overall survival and cancer specific survival were calculated according to the Kaplan-Meier method. RESULTS: 10 patients with a mean age of 67.2 years (range: 57-79) and a median follow up of 78 months (range: 0-89) underwent a total prostatectomy after I-125 implantation (7 patients) or external radiation therapy (3 patients). One patient died after the operation from acute tubular necrosis. One patient developed an internal hernia, requiring surgery. Four patients needed pads during the daytime for stress incontinence for urine. The 5-year progression free survival was 72% (95% confidence interval (95% CI): 44-100), the overall survival was 90% (95% CI: 73-100) and the cancer specific survival was 90% (95% CI: 73-100). No local recurrences were detected. CONCLUSION: The local control and the 5-year survival were good in this selected patient group.

Micronuclei induction by 131I exposure: study in hyperthyroidism patients.

To evaluate the eventual genetic damage induced by therapeutic exposure to 131I, we have studied the presence of micronuclei (MN) in binucleated peripheral blood lymphocytes from a group of 28 hyperthyroidism patients who received 131I sodium iodide, via oral administration. The study was conducted over time and blood samples were obtained before the treatment, and 1 week, 1 month and 3 months after it. The results obtained indicate a positive relationship between dose and BNMN frequency as calculated by the linear regression coefficient, showing significant increases in the frequency of MN and BNMN (binucleated cells with MN) in the subgroup of patients that received more than 500 MBq. Taking into account that the patients studied were treated with relatively low doses of 131I, our positive results support the view that the MN assay is sensitive enough to monitor the chromosome damage resulting from the exposure.