3D MR-Spectroscopic Imaging Assessment of Metabolic Activity in the Prostate During the PSA 'Bounce' Following {sup 125}Iodine Brachytherapy

Journal Article · Tue Feb 01 00:00:00 EST 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.10.066· OSTI ID:21491573

Kirilova, Anna ^[1]; Damyanovich, Andrei ^[2]; Crook, Juanita ^[1]; Jezioranski, John ^[2]; Wallace, Kris ^[1]; Pintilie, Melania ^[3]

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1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto (Canada)
2. Department of Radiation Physics, Princess Margaret Hospital, University of Toronto, Toronto (Canada)
3. Department of Biostatistics, Princess Margaret Hospital, University of Toronto, Toronto (Canada)

Purpose: A temporary increase in prostate-specific antigen (PSA) values is observed in 30%-40% of men following {sup 125} I brachytherapy (BT) for prostate cancer. We present the results of a study to characterize prostate metabolic activity during the PSA 'bounce' and to correlate metabolic changes with PSA levels using three-dimensional magnetic resonance spectroscopic imaging (3D-MRSI). Methods and Materials: 3D-MRSI was performed in 24 patients during the PSA bounce. Eight of these had also had a baseline 3D-MRSI scan before BT for the purpose of tumor mapping. The 3D-MRSI was repeated at 6- and 12-month intervals, and PSA levels were monitored every 3 months. Twenty-one of the patients had favorable-risk prostate cancer, and 3 had intermediate risk. Results: The choline+creatine signal intensity, although markedly reduced, was observable following BT. Diffuse activity not corresponding to original biopsy-positive sites was observed in 22 cases, and 2 cases were documented to have local recurrence. No statistically significant correlation between metabolic activity and PSA levels at each interval was found. Conclusion: Post-BT prostate 3D-MRSI shows evidence of diffuse metabolic activity unrelated to residual malignancy. This supports the benign nature of the PSA bounce and suggests an inflammatory etiology. In the situation of a rising PSA, observation of focal activity on MRI/3D-MRSI could be a useful adjunct to suggest local recurrence at an earlier interval after brachytherapy when prostate biopsies would still be unhelpful. Longer follow-up is necessary to confirm the complex relationship between metabolic activity and PSA levels.

• OSTI ID: 21491573
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 79, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2009.10.066; PII: S0360-3016(09)03551-2; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
ANTIGENS
BRACHYTHERAPY
IODINE 125
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NMR IMAGING
PROSTATE
THREE-DIMENSIONAL CALCULATIONS
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISEASES
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GLANDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
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NUCLEAR MEDICINE
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ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
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