Physical and biological dosimetry in patients undergoing radiosynoviorthesis with erbium-169 and rhenium-186

Abstract

Physical and biological dosimetry were investigated in 45 rheumatoid arthritis patients treated by radiosynoviorthesis (RSO) with 186Re-sulphide (medium-sized joints) and 169Er-citrate (digital joints). Biological dosimetry involved scoring dicentrics in lymphocytes, cultured from blood samples withdrawn just before and 6 h, 24 h and 7 days after treatment. Physical methods included repeated blood sample counts and scintigraphy data. For erbium-169 (pure beta emitter), only bremsstrahlung could be measured and solely in the injection area. For rhenium-186 (both beta and gamma emitter), whole body scans and static images of joints and locoregional lymph nodes were performed. Dosimetry calculations were in accordance with the MIRDOSE 3 software and tables. For erbium-169 (21 patients), either metacarpophalangeal (30 MBq) or proximal interphalangeal (20 MBq) joints of the hands were treated (one joint per patient); 18 patients (out of 21) were interpretable for biological dosimetry, 10 (out of 11) for physical dosimetry and six (out of 10) for both. For rhenium-186, 23 wrists, nine elbows, three shoulders and two ankles were injected in 24 patients, with a maximum of three joints per patient (70 MBq per joint); 20 patients (out of 24) and 10 (out of 10) were interpretable for biological and physical dosimetry, respectively, and eight (out of 10) for both methods. Erbium-169 biological dosimetry was negative in all interpretable patients, and physical dosimetry gave a blood dose of 15 +/- 29 microGy and an effective dose lower than 1 mSv/30 MBq. For rhenium-186, biological results were negative in 16 patients (out of 20), but showed a blood irradiation around 200 mGy in the last four. A significant cumulative increase of dicentrics 7 days after injection (16/10,000 instead of 5/10,000 prior to treatment; p < 0.04) was also noted. Gamma counts gave a blood dose of 23.9 +/- 19.8 mGy/70 MBq and the effective dose was found to be 26.7 +/- 5.1 mGy/70 MBq, i.e. about 380 microGy.MBq-1. Erbium-169 RSO is very safe from both physical and biological dosimetry standpoints. Rhenium-186 leak is greater, as demonstrated by the higher blood activity and the measurable, although limited, dicentrics induction in blood lymphocytes. However, the effective dose remains moderate, i.e. 30 times lower than in 131I therapy in benign thyroid diseases.

Radiosynoviorthesis of acromioclavicular joint using 169Er-citrate: prospective evaluation of efficacy

“…Therefore, the total activity in patients receiving more than two RSOs of the same AC-joint ranged between 111 and 148 MBq corresponding to 69-93% of total cumulative recommended acti vity for two consecutive administrations. In the study of Manil et al [19] the biological dosimetry of 169 Er-citrate measured by scoring dicentrics in lymphocytes cultured from blood samples withdrawn just before and 6 hours, 24 hours and 7 days after RSO was negative in all 18 interpretable patients.…”

Die konservative Lokaltherapie des entzündeten Gelenks

“…[10,15]. Die Wirksamkeit der Therapie ergibt sich aus der lokalen hohen Strahlenbelastung der Synovialis [13,22]. Die rechtfertigende Indikation des Nachweises einer Synovialitis gelingt beispielsweise mit einer Weichteilszintigraphie [26] und wird seitens der Leitlinien der Deutschen Gesellschaft für Nuklearmedizin gefordert [6].…”

Radiosynoviorthese

“…Dosimetrische Untersuchungen nach 169-Erbium-und 186-Rhenium-Injektion in üblicher Dosierung [32] kamen zu dem Ergebnis, dass in Folge einer 169-ErbiumInjektion keine, nach 186-Rhenium-Injektion eine geringe, allerdings 30fach niedrigere als bei Radiojod-Therapie beobachtete Zunahme von Chromosomen-Aberrationen nachweisbar ist. Die über den regionalen Lymphknoten messbare Strahlenintensität ist bei fehlender Gelenk-Immobilisation höher als bei Ruhigstellung [16].…”