Sr-89 therapy: Strontium kinetics in disseminated carcinoma of the prostate

Abstract

Strontium kinetics were investigated in a group of 14 patients receiving 89Sr palliation for metastatic bone disease secondary to prostatic carcinoma. Using 85Sr as a tracer, total body strontium retention R(t) was monitored for a 3 month period following 89Sr administration, and at 90 days was found to vary from 11% to 88% and to correlate closely with the fraction of the skeleton showing scintigraphic evidence of osteoblastic metastatic involvement. Strontium renal plasma clearance varied from 1.6 l/day to 11.6 l/day, and in nine patients was significantly reduced compared with values found in healthy adult men, probably due to increased renal tubular reabsorption associated with the disturbance of calcium homoeostasis. Renal clearance rate was the principal factor determining R(t) for t less than 6 days, and was an important secondary factor at later times. Over the interval 30 days less than t less than 90 days, R(t) was closely fitted by the power law function R(t) = R30 (t/30)-b, with R30 and b showing the close correlation expected from the effect of R(t) on strontium recycling. The correction of the data for this effect to determine the true skeletal release rate is described. Measurement of localized strontium turnover in individual metastatic deposits from whole body profiles and scintigraphic images gave retention curves that typically rose to a plateau by 10 days after therapy, and then decreased very slowly. In contrast, retention curves for adjacent normal trabecular bone showed more rapid turnover, peaking at 1 day and subsequently decreasing following a t-0.2 power law function.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic efficiency of rhenium-188-HEDP in human prostate cancer skeletal metastases

“…No patient showed a decrease in the bone metastases demonstrated on the 99m Tc-HMDP bone scans before treatment when compared to the scans obtained 3 months post-treatment. The bone scan index (BSI) level (Blake et al, 1986) in the group of patients with no response to the 188 Re-HEDP therapy was 54719, in the group of patients with a good response 37714 and in painfree patients 3675 (P ¼ 0.24). In three of the patients, there was a decrease of the number of bone metastases with a mean decrease of the BSI level from 33718 before treatment to 19711 within 1 year after 188 Re-HEDP therapy.…”

Radioisotope therapy of bone metastases

“…As regards nuclear medicine, the Solovay scale or Bone Scan Index (BSI) are used much more frequently [12][13][14][15].…”

Internal Radiation Dosimetry: Models and Applications

“…It is naturally taken up in bone and is a pure β -emitter with a long half-life (50.53 days). Pharmacokinetic and dosimetry studies have been based on imaging of 85 Sr-Cl (Blake, 1986(Blake, , 1987(Blake, , 1998Breen, 1992), although imaging based on bremsstrahlung photons from 89 Sr has also been performed (ICRP, 1997). Tumour dosimetry is generally performed under the assumption that the activity uptake is five times higher than for normal bone.…”