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Author Cederkrantz, Elin ♦ Andersson, Håkan ♦ Bernhardt, Peter ♦ Bäck, Tom ♦ Hultborn, Ragnar ♦ Jacobsson, Lars ♦ Jensen, Holger ♦ Lindegren, Sture ♦ Ljungberg, Michael ♦ Magnander, Tobias ♦ Palm, Stig ♦ Albertsson, Per
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword RADIOLOGY AND NUCLEAR MEDICINE ♦ ABSORBED RADIATION DOSES ♦ ANIMAL TISSUES ♦ ASTATINE 211 ♦ CHEMOTHERAPY ♦ DOSE EQUIVALENTS ♦ GAMMA CAMERAS ♦ NEOPLASMS ♦ OVARIES ♦ PATIENTS ♦ PLANT TISSUES ♦ RBE ♦ SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
Abstract Purpose: Ovarian cancer is often diagnosed at an advanced stage with dissemination in the peritoneal cavity. Most patients achieve clinical remission after surgery and chemotherapy, but approximately 70% eventually experience recurrence, usually in the peritoneal cavity. To prevent recurrence, intraperitoneal (i.p.) targeted α therapy has been proposed as an adjuvant treatment for minimal residual disease after successful primary treatment. In the present study, we calculated absorbed and relative biological effect (RBE)-weighted (equivalent) doses in relevant normal tissues and estimated the effective dose associated with i.p. administration of {sup 211}At-MX35 F(ab'){sub 2}. Methods and Materials: Patients in clinical remission after salvage chemotherapy for peritoneal recurrence of ovarian cancer underwent i.p. infusion of {sup 211}At-MX35 F(ab'){sub 2}. Potassium perchlorate was given to block unwanted accumulation of {sup 211}At in thyroid and other NIS-containing tissues. Mean absorbed doses to normal tissues were calculated from clinical data, including blood and i.p. fluid samples, urine, γ-camera images, and single-photon emission computed tomography/computed tomography images. Extrapolation of preclinical biodistribution data combined with clinical blood activity data allowed us to estimate absorbed doses in additional tissues. The equivalent dose was calculated using an RBE of 5 and the effective dose using the recommended weight factor of 20. All doses were normalized to the initial activity concentration of the infused therapy solution. Results: The urinary bladder, thyroid, and kidneys (1.9, 1.8, and 1.7 mGy per MBq/L) received the 3 highest estimated absorbed doses. When the tissue-weighting factors were applied, the largest contributors to the effective dose were the lungs, stomach, and urinary bladder. Using 100 MBq/L, organ equivalent doses were less than 10% of the estimated tolerance dose. Conclusion: Intraperitoneal {sup 211}At-MX35 F(ab'){sub 2} treatment is potentially a well-tolerated therapy for locally confined microscopic ovarian cancer. Absorbed doses to normal organs are low, but because the effective dose potentially corresponds to a risk of treatment-induced carcinogenesis, optimization may still be valuable.
ISSN 03603016
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-11-01
Publisher Place United States
Journal International Journal of Radiation Oncology, Biology and Physics
Volume Number 93
Issue Number 3


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