|Year : 2011 | Volume
| Issue : 3 | Page : 163-164
Comparison of Tc-99m MDP and Sm-153 EDTMP bone scan
Krishnakumar Ramachandran1, Kathiresan2, Balkis Begum1, Rangarajan1
1 Department of Nuclear Medicine, Cancer Institute (WIA), Adyar, Chennai, India
2 Department of Surgical Oncology, Cancer Institute (WIA), Adyar, Chennai, India
|Date of Web Publication||28-Nov-2012|
Department of Nuclear Medicine, Cancer Institute (WIA), Chennai - 600020
Source of Support: None, Conflict of Interest: None
| Abstract|| |
A 72-year-old male, a known case of carcinoma of prostate, had bilateral orchidectomy in 2002 and while on hormones developed multiple bone metastases in 2010. He was treated with 153 Samarium ethylene diamine tetra methylene phosphonate (EDTMP). The author compares the features of 99m Tc methylene diphosphonate (MDP) scan and 153 Sm EDTMP bone scan, highlighting the similarities of skeletal uptake.
Keywords: Carcinoma prostate, 99m Tc MDP, 153 Sm EDTMP
|How to cite this article:|
Ramachandran K, Kathiresan, Begum B, Rangarajan. Comparison of Tc-99m MDP and Sm-153 EDTMP bone scan. Indian J Nucl Med 2011;26:163-4
|How to cite this URL:|
Ramachandran K, Kathiresan, Begum B, Rangarajan. Comparison of Tc-99m MDP and Sm-153 EDTMP bone scan. Indian J Nucl Med [serial online] 2011 [cited 2020 Jan 20];26:163-4. Available from: http://www.ijnm.in/text.asp?2011/26/3/163/104005
| Introduction|| |
Since mid-1930s, sodium phosphate (NaH2 32PO4), as a soluble orthophosphate, has been used for palliative treatment of multiple widespread painful metastases to bone. Advances in nuclear medicine have now added strontium chloride ( 89 Sr), Samarium [ 153 Sm ethylene diamine tetra methylene phosphonate (EDTMP)] and Rhenium hydroxyethylidene di phosphonate ( 186 Re HEDP).
Samarium has a short physical half-life of 46.3 hours and is one of the shortest lived isotopes in current use for the palliation of bone pain from metastatic disease. 153 Sm decays by a beta emission and gamma photon, allowing imaging of the therapeutic isotope. The beta particle has energies of 810 keV (20%), 710 keV (50%) and 640 keV (30%) which penetrate tissue over a relatively short distance (0.83 mm of water) and a gamma energy 103 keV (29.8% abundance) is suitable for standard scintigraphic imaging. 153 Sm is complexed with EDTMP. The complex remains stable with no measurable breakdown during 48 hours. 
| Case Report|| |
We report a case of a 72-year-old male patient with carcinoma prostrate, who had bilateral orchidectomy in 2002. In 2009, he had reactivation of bone pain and was detected to have cervical vertebral metastases. Radiation was given up to 30 Gy to the vertebrae. The patient was on hormone since then and had monthly Zolendronic acid injection i.v. (14 injections). Serum prostate specific antigen (PSA) was increased (58.8 ng/ml). In 2010, he developed diffuse body ache and 99m Tc methylene diphosphonate (MDP) scan revealed multiple uptake in axial and appendicular skeleton [Figure 1]. Radiogram of chest revealed no pulmonary metastases [Figure 2].
The patient was given a dose of 40 mCi of 153 Sm EDTMP intravenously. After 96 hours, whole body images were acquired (512×512 matrix) - anterior and posterior views. The scan was compared with 99m Tc MDP bone scan. Both revealed abnormal concentration in dorsolumbar vertebrae and skull, besides pelvis and ribs [Figure 3]. The metastases concentrate 153 Sm EDTMP - a prerequiirement for fixed pain relief. The patient had pain relief over a period of 1-2 weeks.
| Discussion|| |
Eary  showed that the distribution of 153 Sm EDTMP was similar to that of 99m Tc MDP and had sensitivity equal to that of 99m Tc MDP bone scanning (lesion to non-lesion bone localization ranged from 2.7 to 6.7). Likewise, 153 Sm EDTMP was found to stay in the skeletal structures for approximately 42 hours and skeletal doses ranged from 20 to 32 rad/mCi with marrow doses ranging from 4.6 to 7.5 rad/mCi.
Another trial  also showed that lesion to normal ratios were 4.04±2.62 for 153 Sm and 4.01±1.9 for 99m Tc MDP. Likewise, ratios of lesion to soft tissue and normal bone to soft tissue were similar between the two agents and 53% of the dose was excreted by the kidneys in the first 8 hours. Clearance studies showed that 5% and 2% remained in the blood at 2 hours and at 4 hours, respectively, after injection.
Dose escalation trials  showed hematologic toxicity in the patients receiving higher doses and they determined a maximum tolerated dose level of 2.5 mCi/kg.
Pain relief typically occurred within 1-2 weeks after treatment, with about 12% showing a flare response after treatment. The lower dose regimen (1 mCi/kg) was compared with higher dose treatment (2.5 mCi/kg) and no definite dose-response relationship was found.  The duration of pain relief and survival was greater for the subgroup that received 153 Sm re-treatment than for the group that received the single-dose treatment.
153 Sm EDTMP holds great promise as a radiopharmaceutical agent for treating pain secondary to metastatic disease. With its imaging gamma photon, favorable beta energy particle, and short physical half-life, the care of patients can be optimized.
| References|| |
|1.||Eary JF, Collins C, Stabin M, Vernon C, Petersdorf S, Baker M, et al. 153 Samarium EDTMP biodistribution and dosimetry estimation. J Nucl Med 1993;34:1031-6. |
|2.||Singh A, Holmes RA, Farhangi M, Volkert WA, Williams A, Stringham LM, et al. Human Pharmacokinetics of 153 Samarium EDTMP in metastatic cancer. J Nucl Med 1989;30:1814-8. |
|3.||Collins C, Eary JF, Donaldson G, Vernon C. 153 Samarium EDTMP in bone metastases of hormone refractory prostate carcinoma: A phase I/II trial, J Nucle Med 1993;34:1839-44. |
|4.||Turner JH, Martindale AA, Sorby P, Hetherington EL, Fleay RF, Hoffman RF, et al. 153 Samarium EDTMP therapy of disseminated skeletal metastasis. Eur J Nucl Med 1989;15:784-95. |
[Figure 1], [Figure 2], [Figure 3]