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Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA(0),Tyr(3)]octreotate.

Forrer F, Krenning EP, Kooij PP, Bernard BF, Konijnenberg M, Bakker WH, Teunissen JJ, de Jong M, van Lom K, de Herder WW, Kwekkeboom DJ - Eur. J. Nucl. Med. Mol. Imaging (2009)

Bottom Line: Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously.A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001).No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Erasmus MC Rotterdam, Dr. Molewaterplein 40, NL-3015 GD, Rotterdam, The Netherlands. fforrer@uhbs.ch

ABSTRACT

Purpose: Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the accumulated activity in the bone marrow is calculated from the accumulated radioactivity of the radiopharmaceutical in the blood. This may underestimate the absorbed dose since stem cells express somatostatin receptors. We verified the blood-based method by comparing the activity in the blood with the radioactivity in bone marrow aspirates. Also, we evaluated the absorbed cross-dose from the source organs (liver, spleen, kidneys and blood), tumours and the so-called "remainder of the body" to the bone marrow.

Methods: Bone marrow aspirates were drawn in 15 patients after treatment with [(177)Lu-DOTA(0),Tyr(3)]octreotate. Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously. The nucleated cell fraction was isolated from the bone marrow aspirate and radioactivity was measured. The absorbed dose to the bone marrow was calculated. The results were correlated to the change in platelet counts 6 weeks after treatment.

Results: A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001). No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found. There was a considerable contribution from other organs and the remainder of the body to the bone marrow absorbed dose.

Conclusion: (1) After PRRT with [(177)Lu-DOTA(0),Tyr(3)]octreotate, the radioactivity concentration in the bone marrow is identical to that in the blood; (2) There is no significant binding of the radiopharmaceutical to bone marrow precursor stem cells; (3) The contribution of the cross dose from source organs and tumours to the bone marrow dose is significant; and (4) There is considerable variation in bone marrow absorbed dose between patients. These findings imply that for individual dose optimization, individual calculation of the bone marrow absorbed dose is necessary.

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Correlation between the activities measured in the bone marrow aspirate and the activities measured in the blood at the same time-points. The straight line is the linear regression line: r=0.914, p<0.001. The slope of the regression line is 1.35 indicating that the absolute values of the measured activities are also comparable
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Fig2: Correlation between the activities measured in the bone marrow aspirate and the activities measured in the blood at the same time-points. The straight line is the linear regression line: r=0.914, p<0.001. The slope of the regression line is 1.35 indicating that the absolute values of the measured activities are also comparable

Mentions: The radioactivity in the full bone marrow samples ranged from 850 to 4,473 Bq/ml (2,216±899 Bq/ml). The radioactivity in the blood ranged from 1,077 to 6,451 Bq/ml (2,437±1,324 Bq/ml). Fitting the correlation line through the origin (0,0) as seems right from a theoretical point of view, showed a strong, significant, linear correlation between the radioactivity determined in the blood and in the bone marrow aspirate (y=1.13x, r=0.90, p<0.001; Fig. 2). This results in a mean red marrow over blood ratio of 0.88 (value not significantly different from 1). Both qualitatively and quantitatively the results showed strong agreement over a whole range of activities at the three different time-points.Fig. 2


Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA(0),Tyr(3)]octreotate.

Forrer F, Krenning EP, Kooij PP, Bernard BF, Konijnenberg M, Bakker WH, Teunissen JJ, de Jong M, van Lom K, de Herder WW, Kwekkeboom DJ - Eur. J. Nucl. Med. Mol. Imaging (2009)

Correlation between the activities measured in the bone marrow aspirate and the activities measured in the blood at the same time-points. The straight line is the linear regression line: r=0.914, p<0.001. The slope of the regression line is 1.35 indicating that the absolute values of the measured activities are also comparable
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2691529&req=5

Fig2: Correlation between the activities measured in the bone marrow aspirate and the activities measured in the blood at the same time-points. The straight line is the linear regression line: r=0.914, p<0.001. The slope of the regression line is 1.35 indicating that the absolute values of the measured activities are also comparable
Mentions: The radioactivity in the full bone marrow samples ranged from 850 to 4,473 Bq/ml (2,216±899 Bq/ml). The radioactivity in the blood ranged from 1,077 to 6,451 Bq/ml (2,437±1,324 Bq/ml). Fitting the correlation line through the origin (0,0) as seems right from a theoretical point of view, showed a strong, significant, linear correlation between the radioactivity determined in the blood and in the bone marrow aspirate (y=1.13x, r=0.90, p<0.001; Fig. 2). This results in a mean red marrow over blood ratio of 0.88 (value not significantly different from 1). Both qualitatively and quantitatively the results showed strong agreement over a whole range of activities at the three different time-points.Fig. 2

Bottom Line: Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously.A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001).No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found.

View Article: PubMed Central - PubMed

Affiliation: Department of Nuclear Medicine, Erasmus MC Rotterdam, Dr. Molewaterplein 40, NL-3015 GD, Rotterdam, The Netherlands. fforrer@uhbs.ch

ABSTRACT

Purpose: Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the accumulated activity in the bone marrow is calculated from the accumulated radioactivity of the radiopharmaceutical in the blood. This may underestimate the absorbed dose since stem cells express somatostatin receptors. We verified the blood-based method by comparing the activity in the blood with the radioactivity in bone marrow aspirates. Also, we evaluated the absorbed cross-dose from the source organs (liver, spleen, kidneys and blood), tumours and the so-called "remainder of the body" to the bone marrow.

Methods: Bone marrow aspirates were drawn in 15 patients after treatment with [(177)Lu-DOTA(0),Tyr(3)]octreotate. Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously. The nucleated cell fraction was isolated from the bone marrow aspirate and radioactivity was measured. The absorbed dose to the bone marrow was calculated. The results were correlated to the change in platelet counts 6 weeks after treatment.

Results: A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001). No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found. There was a considerable contribution from other organs and the remainder of the body to the bone marrow absorbed dose.

Conclusion: (1) After PRRT with [(177)Lu-DOTA(0),Tyr(3)]octreotate, the radioactivity concentration in the bone marrow is identical to that in the blood; (2) There is no significant binding of the radiopharmaceutical to bone marrow precursor stem cells; (3) The contribution of the cross dose from source organs and tumours to the bone marrow dose is significant; and (4) There is considerable variation in bone marrow absorbed dose between patients. These findings imply that for individual dose optimization, individual calculation of the bone marrow absorbed dose is necessary.

Show MeSH
Related in: MedlinePlus