Current Role and Future Perspectives of Magnetic Resonance Spectroscopy in Radiation Oncology for Prostate Cancer

Abstract

Prostatic neoplasms are not uniformly distributed within the prostate volume. With recent developments in three-dimensional intensity-modulated and image-guided radiation therapy, it is possible to treat different volumes within the prostate to different thresholds of doses. This approach has the potential to adapt the dose to the biologic aggressiveness of various clusters of tumor cells within the gland. The definition of tumor burden volume in prostate cancer can be facilitated by the use of magnetic resonance spectroscopy (MRS). The increasing sensitivity and specificity of MRS to the prostate is causing new interest in its potential role in the definition of target subvolumes at higher risk of failure following radical radiotherapy. Prostate MRS might also play a role as a noninvasive predictive factor for tumor response and treatment outcome. We review the use of MRS in radiation therapy for prostate cancer by evaluating its accuracy in the classification of aggressive cancer regions and target definition; its current role in the radiotherapy planning process, with special interest in technical issues behind the successful inclusion of MRS in clinical use; and available early experiences as a prognostic tool.

The use of magnetic resonance imaging for image‐guided brachytherapy

“…It offers the possibility of integrat-ing biological and anatomical images for accurate localisation of intraprostatic tumour. 16 Functional magnetic resonance techniques include: dynamic contrastenhanced MRI (DCE MRI), magnetic resonance spectroscopy (MRS), blood oxygen level-dependent MRI (BOLD MRI) and diffusion-weighted MRI (DW MRI). [17][18] These studies can also be used to precisely map dosimetry within the gland and assess changes that occur during radiotherapy.…”

“…MRI technology also allows functional assessment of the prostate. It offers the possibility of integrating biological and anatomical images for accurate localisation of intraprostatic tumour 16 . Functional magnetic resonance techniques include: dynamic contrast‐enhanced MRI (DCE MRI), magnetic resonance spectroscopy (MRS), blood oxygen level‐dependent MRI (BOLD MRI) and diffusion‐weighted MRI (DW MRI) 17–18 .…”

A review of image-guided radiotherapy

“…The first category includes aspects of imaging and target delineation for image-guided therapy [21][22][23][24][25][26]. IGRT clearly requires accurate delineation of the target as a prerequisite for high-precision radiation delivery.…”

CADOnc ⓒ: An integrated toolkit for evaluating radiation therapy related changes in the prostate using multiparametric MRI

“…While such multi-parametric MRI-based biomarkers for evaluating RT-related changes within CaP regions have been identified, the qualitative examination of post-RT MRI is associated with poor detection rates due to (a) diffuse T2w signal intensity and indistinct zonal anatomy on T2w MRI [6], (b) adverse effects of post-biopsy hemorrhage and hormonal therapy on metabolic peaks [7], and (c) significant gland shrinkage and distortion post-RT [1]. Automated quantitative assessment of RT changes via multi-parametric MRI may thus allow accurate identification of (a) residual disease, and (b) new foci of cancer (local recurrence) within the prostate.…”