What is the best pre-therapeutic dosimetry for successful radioiodine therapy of multifocal autonomy?

2006 ◽  
Vol 45 (05) ◽  
pp. 206-212 ◽  
Author(s):  
C. Rubner ◽  
A. Bauhofer ◽  
F. Berce ◽  
W. J. G. Oyen ◽  
J. Goecke ◽  
...  
Keyword(s):  
Half Life ◽  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Dose Calculation ◽  
Target Dose ◽  
Therapeutic Success ◽  
Organ Doses ◽  
Therapeutic Activities ◽  
Higher Doses

Summary:Purpose: Dose calculation for radioiodine therapy (RIT) of multifocal autonomies (MFA) is a problem as therapeutic outcome may be worse than in other kinds of autonomies. We compared different dosimetric concepts in our patients. Patients, methods: Data from 187 patients who had undergone RIT for MFA (Marinelli algorithm, volumetric compromise) were included in the study. For calculation, either a standard or a measured half-life had been used and the dosimetric compromise (150 Gy, total thyroid volume). Therapeutic activities were calculated by 2 alternative concepts and compared to therapeutic success achieved (concept of TcTUs-based calculation of autonomous volume with 300 Gy and TcTUs-based adaptation of target dose on total thyroid volume). Results: If a standard half-life is used, therapeutic success was achieved in 90.2%(hypothyroidism 23,1%, n=143). If a measured half-life was used the success rate was 93.1% (13,6% hypothyroidism, n=44). These differences were statistically not significant, neither for all patients together nor for subgroups eu-, hypo-, or hyperthyroid after therapy (ANOVA, all p>0.05). The alternative dosimetric concepts would have resulted either in significantly lower organ doses (TcTUs-based calculation of autonomous volume; 80.76±80.6 Gy versus 125.6±46.3 Gy; p<0.0001) or in systematic over-treatment with significantly higher doses (TcTUs-adapted concept; 164.2±101.7 Gy versus 125.6±46.3 Gy; p=0.0097). Conclusions: TcTUsbased determination of the autonomous volume should not be performed, the TcTUs-based adaptation of the target dose will only increase the rate of hypothyroidism. A standard half-life may be used in pre-therapeutic dosimetry for RIT of MFA. If so, individual therapeutic activities may be calculated based on thyroid size corrected to the 24h ITUs without using Marinelli’s algorithm.

Results of a risk adapted and functional radioiodine therapy in Graves’ disease

2005 ◽  
Vol 44 (06) ◽  
pp. 238-242 ◽  
Author(s):  
V. Neumann ◽  
U. Staub ◽  
P. Groth ◽  
H. Künstner ◽  
C. Schümichen ◽  
...  
Keyword(s):  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Therapeutic Failure ◽  
Graves Disease ◽  
Clinical Parameters ◽  
Target Dose ◽  
Therapeutic Success ◽  
Thyroid Metabolism ◽  
First Time

SummaryAim of this study was to find out, if results of a functional orientated radioiodine therapy in Graves’ disease could be optimized using a risk adopted dose concept. Patients, method: 351 patients with Graves’ disease were treated for the first time between 11/97 and 8/01. The basic dose was 125 Gy, which was increased up to 250 Gy in a cumulative manner depending on clinical parameters (initial thyroid metabolism, thyroid volume, immunoreactivity). Two different methods of dosimetry were used. Occasional thyreostasis was withdrawn two days before the radioiodine test was started. Follow up was done on average 8 ± 2,4 (4-17,2) months. TSH ≥0,27 μIU/mL confirmed as a measure of the success. Results: With improved pretherapeutic dosimetry and a mean target dose of 178 ± 31 Gy (n=72) therapeutic success occurred in 66,7%, in 51,4% euthyreosis was restalled and in 15,3% of patients hypothyroidism was seen (TSH >4,20 μIU/mL). With simplified pretherapeutic dosimetry and a mean target dose of 172 ± 29 Gy (n=279) results were moderately impaired (63,8%, 40,1% and 23,7%). With increasing target dose therapeutic failure increased, as unsufficiently adopted risk factors for therapeutic failure turned out the initial thyroid metabolism, the TcTU(s) as the (h)TRAb titer. Conclusion: Functional orientated RIT can be optimized by including illness specific characteristics, principal limitations are a high initial thyroid metabolism, a large thyroid volume and a high (h)TRAb-titer.

Does an individual estimation of halflife improve the results of radioiodine therapy of Graves’ disease?

2002 ◽  
Vol 41 (06) ◽  
pp. 240-244 ◽  
Author(s):  
C. Körber ◽  
N. Körber-Hafner ◽  
H. Hänscheid ◽  
Chr. Reiners ◽  
P. Schneider
Keyword(s):  
Radioiodine Therapy ◽  
Dose Calculation ◽  
Multiple Regression Model ◽  
Therapeutic Outcome ◽  
Graves Disease ◽  
Therapeutic Success ◽  
Logit Transformation ◽  
Therapy Success ◽  
The Impact ◽  
Delivered Dose

SummaryAim: The impact of our dosimetry concept on radioiodine therapy success in Graves’ disease (GD) was analysed. Three questions arised: Did individual estimation of pretherapeutic halflife improve therapeutic success?. Did individual dosimetry result in accurate dose calculation?. Did antithyroid medication have a measurable influence on therapeutic success under the prevailing conditions?. Methods: 126 consecutive patients were treated with 200 Gy I-131 in our therapy ward for GD and followed-up six to nine months after therapy. Success quote was assessed using a standardized protocol and treatment was classified as successful when the patient was eu- or hypothyroid, or unsuccessful when he or she presented with a suppressed TSH-level or in hyperthyroid condition after antithyroid medication withdrawel. Antithyroid medication, activity I-131, dose, concentration of fT3 and fT4, specific delivered dose and halflife were put into a multiple regression model to assess their influence on therapeutic success. In order to assess possible factors disturbing the therapeutic outcome, relevant parameters were analyzed using Logit transformation. Results: Out of 126 patients 84 were classified as successfully treated and 42 (33,3%) as failures. A significant influence on the outcome only was found for thyroid mass. However, therapeutic success appeared to be more distinctly determined by the specific delivered dose using an estimated halflife of 5.5 days (Odds: 10.0, p <0.001). Accurate intratherapeutic dosimetry did not play a significant role to enhance therapeutic success. Neither did antihyroid medication during radioiodine therapy exert any significant impact. Conclusions: Measurement of individual intratherapeutic halflife as opposed to an estimate using a standard halflife did not provide improved results concerning the target dose. Retrospectively, the therapeutic outcome on the basis of a measured halflife as compared to a standard halflife did not significantly improve. In addition, no influence of antithyroid medication on therapy success was found.

Radioiodine therapy of Graves’ disease — a dosimetric comparison of different strategies concerning antithyroid drugs

2001 ◽  
Vol 40 (04) ◽  
pp. 111-115 ◽  
Author(s):  
V. Urbannek ◽  
E. Voth ◽  
D. Moka ◽  
H. Schicha
Keyword(s):  
Half Life ◽  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Absorbed Dose ◽  
The Body ◽  
Antithyroid Drugs ◽  
Graves Disease ◽  
Thyroid Metabolism ◽  
Group A ◽  
Group B

SummaryAim: Premedication with antithyroid drugs (ATD) compared to patients not pretreated with ATD causes a higher failure rate of radioiodine therapy (RITh) or demands higher therapeutical dosage of radioiodine (Rl). For clinical reasons and because of accelerated iodine metabolism in hyperthyreosis a compensated thyroid metabolism is desirable. Aim of this study was to investigate the influence of ATD on the biokinetics of Rl in case of Graves’ disease in order to improve RITh of patients pretreated with ATD. Methods: 385 consecutive patients who underwent RITh because of Graves’ disease for the first time were included: Group A (n = 74): RITh under continuous medication with ATD; Group B (ç = 111): Application of Rl under continuous medication with ATD, in case of insufficient Rl-uptake or shortened effective Rl-half-life ATD were stopped 1-5 days after RITh; Group C (n = 200): ATD were stopped 2 days prior to RITh in all patients. We examined the influence of ATD on Rl-uptake and effective Rl-half-life as well as the absorbed dose achieved on the thyroid in dependence of thyroid volume and applied Rl-dosage [TEQ - therapy efficiency quotient, (2)]. Results: In the Rl-pretest (all patients under ATD) the Rl-uptake was comparable in all three groups. During RITh Rl-uptake, effective Rl-half-life and therefore the TEQ were significantly higher in Group C as compared to Groups A and B (ñ <0,001, respectively). In Group B the medication with ATD was stopped in 61 of 111 cases 1-5 days after RITh. In this subgroup the effective Rl-half-life increased from 4,4 ± 1,7 d to 5,1 ± 1,6 d after stopping of ATD (ñ = 0,001). Conclusion: Stopping of ATD 2 days prior to RITh leads to an increased efficiency of about 50% compared to RITh carried out under ATD and therefore to a clear reduction of radiation exposure to the rest of the body with equal absorbed doses of the thyroid. Stopping of ATD shortly after RITh increases efficiency in case of short effective Rl-half-life, but it is inferior to stopping ATD 2 days prior to RITh.

Reduced radioiodine uptake at increased iodine intake and 131I-induced release of “cold” iodine stored in the thyroid

2005 ◽  
Vol 44 (04) ◽  
pp. 137-142 ◽  
Author(s):  
A. Haase ◽  
M. Seyfarth ◽  
B. E. Wenzel ◽  
E. Richter ◽  
M. Baehre ◽  
...  
Keyword(s):  
Radioiodine Therapy ◽  
Urinary Iodine ◽  
Thyroid Volume ◽  
Target Volume ◽  
Iodine Intake ◽  
Urinary Iodine Excretion ◽  
Target Dose ◽  
Radioiodine Uptake ◽  
Iodine Excretion ◽  
Iodine Release

Summary Aim: The extent of urinary iodine excretion (UIE) provides information about iodine supply and release. In the present study we investigated correlations between UIE and radioiodine uptake (RIU) as well as effects of radioiodine therapy on UIE in patients with autonomous goitre. Patients, methods: In 197 consecutive patients with thyroid autonomy, UIE was measured twice during radioiodine test (RITe) and correlated with RIU. In 98 of these patients, thyroglobulin and thyroid volume (V) were determined prior to therapy. Individual changes in urinary iodine excretion (ΔUIE) and TG (ΔTG) could be investigated four weeks (4W) and six months (6M) after radioiodine therapy. Additionally, ΔV was determined 6M after therapy. ΔUIE, ΔTG and ΔV were correlated with target dose and target volume. Results: Patients with higher iodine excretion exhibited significantly lower thyroidal radioiodine uptake values. Twofold increased UIE prior to therapy decreased radioiodine uptake by 25%. Compared with pretherapeutic values, UIE and TG were significantly increased four weeks after radioiodine therapy (p <0.001). Median values of both parameters were found to be doubled. The product of target dose and target volume was not only correlated with a decrease of thyroid volume 6M after therapy, but also with an increase of UIE and TG in the early phase after therapy. Conclusions: It was confirmed that UIE during RITe is a measure for iodine intake and can be used to investigate the competition between stable iodine and radioiodine. The increase of UIE and TG four weeks after therapeutic administration of radioiodine can be explained by disintegrated thyroid follicles. The therapy-induced iodine release may be one important cause for the development of hyperthyroidism in some patients during the first weeks after radioiodine therapy. It may contribute to the known decrease of radioiodine uptake after preapplications of 131I in various thyroid diseases.

Radioiodine therapy in Graves' hyperthyroidism: Determination of individual optimum target dose

2000 ◽  
Vol 108 (02) ◽  
pp. 133-137 ◽  
Author(s):  
A. Haase ◽  
M. Bähre ◽  
I. Lauer ◽  
B. Meller ◽  
E. Richter
Keyword(s):  
Radioiodine Therapy ◽  
Target Dose

The Effect of Carbimazole Following Radioiodine Therapy on Radiation Dose to the Thyroid

1981 ◽  
Vol 20 (02) ◽  
pp. 72-75 ◽  
Author(s):  
R. Kocak ◽  
R.G. Herbert ◽  
C.R. Squire ◽  
T.M.D. Gimlette
Keyword(s):  
Thyroid Gland ◽  
Radiation Dose ◽  
Half Life ◽  
Radioiodine Therapy

Radioiodine in the thyroid gland after a therapy dose of 131I was measured serially in 7 patients without Carbimazole, and in 11 patients starting Carbimazole 60 mg daily fourteen days after the therapy dose. Effective half-life for radioiodine in the gland initially 5.53±1.08 days fell to 4.26±1.12 days (p < 0.01) during Carbimazole, and returned to 5.83±1.21 days (NS) after stopping the drug. The radiation dose to the thyroid from a given therapy dose of 131I followed by Carbimazole was calculated to be 97% of that without Carbimazole when the drug was started after 14 days, and 90% and 75% when the drug was started after 7 days and 1 day respectively.

Characterization of radioiodine therapy failures in Graves’ disease

2001 ◽  
Vol 40 (01) ◽  
pp. 1-6 ◽  
Author(s):  
M. Zimny ◽  
M. Schreckenberger ◽  
P. Reinartz ◽  
B. Nowak ◽  
E. Ostwald ◽  
...  
Keyword(s):  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Absorbed Dose ◽  
Stepwise Logistic Regression ◽  
Graves Disease ◽  
Significant Variable ◽  
Absorbed Energy ◽  
Volume Function ◽  
Energy Dose

Summary Aim of this study was a characterization of radioiodine therapy (RIT) failures in Graves’ disease without simultaneous Carbimazole. Method: 226 patients with a confirmed diagnosis of Graves’ disease received 686.8 ± 376.4 MBq of iodine-131 orally for thyroid ablation. Target dose was 250 Gy. All patients were followed up for 6 months. Therapy failures were compared with successes regarding possible influencing variables initial thyroid volume, thyroid function, immune activity (TRAb), 1-131 uptake, effective half-life, absorbed energy dose, age and gender. Results: 212 of 226 patients (93.8%) were treated successfully, 14 (6.2%) showed a hyperthyroidism relapse within 6 months which required a second radioiodine therapy. A success rate of 92.5% (62/67) could also be achieved with 67 patients who were hyperthyroid at the time of RIT. Compared to the therapy successes, the 14 failures achieved significantly lower absorbed doses (223.8 ±76.6 Gyvs. 285.2 ±82.1 Gy, ρ <0.005), but with no significant differences regarding age, thyroid volume, function or TRAb (all ρ >0.2). Of the 14 failures, η = 8 reached an absorbed dose <200 Gy and η = 1 a dose <250 Gy, although 5 of the failures reached an absorbed dose of >250 Gy. Stepwise logistic regression revealed only absorbed energy dose as a variable significantly influencing therapy success (p <0.005), but no influence of initial thyroid volume, function, TRAb value, age (all ρ >0.2) or gender (p = 0.13). Two-tailed Fisher’s exact test showed no significant influence of gender on success rates (failures/successes: male 1 /36, female 13/176, ρ = 0.48). Conclusions: Except for the absorbed energy dose, no other significant variable influencing the outcome of radioiodine therapy in Graves’ disease without simultaneous Carbimazole could be found. It should be noted, though, that 5 therapy failures (2.2%) reached an absorbed energy dose of >250 Gy.

Guideline for radioiodine therapy for benign thyroid diseases (version 3)

2004 ◽  
Vol 43 (06) ◽  
pp. 217-220 ◽  
Author(s):  
J. Dressler ◽  
F. Grünwald ◽  
B. Leisner ◽  
E. Moser ◽  
Chr. Reiners ◽  
...  
Keyword(s):  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Thyroid Diseases ◽  
Antithyroid Drugs ◽  
Graves Disease ◽  
Co Morbidity ◽  
History Of ◽  
Individual Decisions ◽  
Prophylactic Use ◽  
Benign Thyroid

SummaryThe version 3 of the guideline for radioiodine therapy for benign thyroid diseases presents first of all a revision of the version 2. The chapter indication for radioiodine therapy, surgical treatment or antithyroid drugs bases on an interdisciplinary consensus. The manifold criteria for decision making consider the entity of thyroid disease (autonomy, Graves’ disease, goitre, goitre recurrence), the thyroid volume, suspicion of malignancy, cystic nodules, risk of surgery and co-morbidity, history of subtotal thyroidectomy, persistent or recurrent thyrotoxicosis caused by Graves’ disease including known risk factors for relapse, compression of the trachea caused by goitre, requirement of direct therapeutic effect as well as the patient’s preference. Because often some of these criteria are relevant, the guideline offers the necessary flexibility for individual decisions. Further topics are patients’ preparation, counseling, dosage concepts, procedural details, results, side effects and follow-up care. The prophylactic use of glucocorticoids during radioiodine therapy in patients without preexisting ophthalmopathy as well as dosage and duration of glucocorticoid medication in patients with preexisting ophthalmopathy need to be clarified in further studies. The pragmatic recommendations for the combined use of radioiodine and glucocorticoids remained unchanged in the 3rd version.

A determination of the half-life of14C

1968 ◽  
Vol 58 (1) ◽  
pp. 232-246 ◽  
Author(s):  
F. Bella ◽  
M. Alessio ◽  
P. Fratelli
Keyword(s):  
Half Life
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