Exp Clin Endocrinol Diabetes 2000; Vol. 108(2): 133-137
DOI: 10.1055/s-2000-5807
Articles

© Johann Ambrosius Barth

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

A. Haase, M. Bähre, I. Lauer, B. Meller, E. Richter
  • Department of Radiotherapy and Nuclear Medicine, Medical University of Lübeck, Lübeck, Germany
Further Information

Publication History

Publication Date:
31 December 2000 (online)

Summary:

The aim of this study was to investigate the results of different volume-dependent target doses on clinical outcome 6 months after radioiodine therapy (RITh) and its correlation with post therapeutic thyroid volumes (Vpost) in patients with Graves' disease. This analysis was designed to determine factors improving the results of radioiodine therapy without increasing target doses generally, as has been recommended recently. We studied consecutive data from 102 patients with Graves' disease, who had initial radioiodine therapy between 1991 and 1995. The 131I activities were calculated according to the formula of Marinelli. In addition to the normal calculation individual target doses were adjusted to the thyroid volumes of each patient before therapy. For statistical evaluation, the patients were divided into three subgroups of comparable sample sizes: Group I included those with a thyroid volume < 15 ml before therapy. Group II included those ranging from a 15-25 ml volume before therapy and group III included those with thyroid volumes > 25 ml. Laboratory thyroid parameters and thyroid volumes were measured in those groups before and 6 months after therapy. Results: Analysis of all patients revealed a significantly higher rate of hypothyroidism (54%) and fewer cases of hyperthyroidism (15%) six months after therapy in cases with Vpost smaller than 8 ml. The median Vpost needed to achieve an optimum therapeutic success rate (rate of eu- or hypothyroidism) was smaller than 5 ml in group I and smaller than 10 ml in group II. Therapeutic success was associated with different target doses in each group, 150, 220 and 260 Gy for groups I, II, and III respectively. Conclusions: Post therapeutic thyroid volumes correlated significantly with clinical outcome six months after therapy. An adjustment of the target doses based on thyroid volumes before therapy will lead to an appropriate reduction of thyroid volumes. Thus, in the individual case clinical outcome could be improved without applying higher target doses in all patients. This would ensure a better utilization of limited resources in medical care e.g. through a shorter hospital stay.

References

  • 1 de Bruin T WA, Croon C DL, de Klerk J MH, van Isselt J W. Standardized radioiodine therapy in Graves' disease: The persistent effect of thyroid weight and radioiodine uptake on outcome.  J Intern Med. 236 507-513 1994; 
  • 2 Dederich B, Otte R, Klink J E, Schicha H. Volumenreduktion der Schilddrüse nach Radioiodtherapie bei Patienten mit Schilddrüsenautonomie und M. Basedow.  Nuklearmedizin. 35 164-169 1996; 
  • 3 Emrich D. Muß die hohe Hpyothyreoserate nach Radioiodtherapie einer immunogenen Hyperthyreose in Kauf genommen werden?.  Nuklearmedizin. 36 5 1997; 
  • 4 Farrar J J, Toft A D. Iodine-131 treatment of hyperthyroidism: Current issues.  Clin Endocrinol. 35 207-212 1991; 
  • 5 Francklyn J A, Daykin J, Drolc Z, Farmer M, Sheppard C. Long-term follow-up of treatment of thyrotoxicosis by three different methods.  Clin Endocrinol. 34 71-76 1991; 
  • 6 Goretzki P E, Frilling A, Grussendorfer M, Horster A H, Röher H D. Operative Therapie der immunogenen und nicht-immunogenen Hyperthyreose. Eigene Ergebnisse bei Standardverfahren.  Akt Endokrin Stoffw. 13 43-46 1992; 
  • 7 Guhlmann C A, Rendl J, Börner W. Radioiodtherapie der funktionellen Autonomie und des M. Basedow.  Nuklearmedizin. 34 20-23 1995; 
  • 8 Kasuga Y, Sugenoya A, Kobayashi S, Kaneko G, Masuda H, Fujimoto M, Lida F. Clinical evaluation of the response to surgical treatment of Graves' disease.  Surg Gynecol Obstet. 170 327 1990; 
  • 9 Köster O, Franken T, Baumgarten C. Vergleichende computertomographische, sono- und szintigraphische Volumenmessung der Schilddrüse.  Nuc compact. 2 54-60 1982; 
  • 10 Marinelli L D, Quimby E H, Hine G J. Dosage determination with radioactive isotopes, practical considerations in therapy and protection.  Am J Roentgenol. 2 260-281 1948; 
  • 11 Moser E. Ergebnisse der Radioiodtherapie bei den unterschiedlichen Formen der Hperthyreose in Abhängigkeit vom Dosiskonzept.  Akt Radiol. 2 179-187 1992; 
  • 12 Peters H, Fischer C, Bogner U, Reiners C, Schleusener H. Radioiodine therapy of Graves' hyperthyroidism: Standard vs. calculated 131iodine activity. Results from a prospective, randomized, multicentre study.  Eur J Nucl Med. 25 186-193 1995 a; 
  • 13 Peters H, Fischer C, Bogner U, Reiners C, Schleusener H. Reduction in thyroid volume after radioiodine therapy of Graves' hyperthyroidism: Results of a prospective, randomized, multicentre study.  Eur J Nucl Med. 26 59-63 1995 b; 
  • 14 Pfeilschifter J, Elser H, Haufe S, Ziegler R, Georgi P. Einfluß prätherapeutischer Variablen auf die Wirkung einer standardisierten 131I-Therapie mit 150 Gy beim Morbus Basedow.  Nuklearmedizin. 36 81-86 1997; 
  • 15 Reiners Ch. Aktuelle Gesichtspunkte der Radioiodbehandlung der Hyperthyreose vom Typ M. Basedow.  Akt Endokr Stoffw. 10 125-132 1989; 
  • 16 Schicha H. Behandlung mit Radioiod bei immunogener Hyperthyreose. In: Pickardt CR, Pfannenstiel P, Weinheimer B: Schilddrüse 1987. Thieme, Stuttgart 1987
  • 17 Sugino K, Mimura T, Toshima K, Iwabuchi H, Kitamura Y, Kawano M, Ozaki O, Ito K. Follow-up evaluation of patients with Graves' disease treated by subtotal thyroidectomy and risk factors for post operative thyroid function.  J Endocrinol Invest. 16 195-199 1993; 
  • 18 Willemsen U F, Knesewitsch P, Kreisig T, Pickardt C R, Kirsch C M. Functional results of radioiodine therapy with a 300-Gy absorbed dose in Graves' disease.  Eur J Nucl Med. 20 1051-1055 1993; 

Dr. Alexandra Haase

Medizinische Universität zu Lübeck

Klinik für Strahlentherapie und Nuklearmedizin

Ratzeburger Allee 160

D-23538 Lübeck

Phone: 04 51/5 00-66 71

Fax: 04 51/5 00-66 68

Email: haase@stnuk.mu-luebeck.de