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The potential role of magnetic resonance spectroscopy in image-guided radiotherapy.

Nguyen ML, Willows B, Khan R, Chi A, Kim L, Nour SG, Sroka T, Kerr C, Godinez J, Mills M, Karlsson U, Altdorfer G, Nguyen NP, Jendrasiak G, International Geriatric Radiotherapy Gro - Front Oncol (2014)

Bottom Line: Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues.Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe.Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Stanford University , Palo Alto, CA , USA.

ABSTRACT
Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues. The ability of MRS to diagnose areas of high metabolic activity linked to tumor cell proliferation is particularly useful for radiotherapy treatment planning because of better gross tumor volume (GTV) delineation. The GTV may be targeted with higher radiation dose, potentially improving local control without excessive irradiation to the normal adjacent tissues. Prostate cancer and glioblastoma multiforme (GBM) are two tumor models that are associated with a heterogeneous tumor distribution. Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe. Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

No MeSH data available.


Related in: MedlinePlus

This patient has a biopsy-proven adenocarcinoma of the prostate in the magnetic resonance spectroscopy area suspicious for malignancy. Axial (A), Coronal (B), and sagittal (C) high-resolution T2-weighted images. Axial diffusion weighted, b = 2000 (D) and ADC map (E). 1H-spectroscopy demonstrating elevated choline/creatine-to-citrate ratio (F).
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Figure 2: This patient has a biopsy-proven adenocarcinoma of the prostate in the magnetic resonance spectroscopy area suspicious for malignancy. Axial (A), Coronal (B), and sagittal (C) high-resolution T2-weighted images. Axial diffusion weighted, b = 2000 (D) and ADC map (E). 1H-spectroscopy demonstrating elevated choline/creatine-to-citrate ratio (F).

Mentions: Magnetic resonance spectroscopy is particularly helpful to distinguish radiation injury from tumor recurrence after radiotherapy as both may have similar magnetic resonance imaging (MRI) appearances (1). Decreased in Cho, NAA, and Cr are usually observed with radiation injury and high Cho/NAA ratio is suggestive of tumor recurrence (2). In the prostate, Citrate (Cit) is produced by the normal prostate epithelium. The prostate has a high concentration of mitochondrial Zinc (Zn), which inhibits aconitase, the first enzyme of the Krebs cycle, which normally converts citrate to isocitrate leading to a high concentration of citrate in the prostatic epithelium (3). Cit is often decreased in area of prostate adenocarcinoma because of the low Zn concentration. High Cho and Cr are also observed in tumor areas because of cancer cells proliferation. Thus, higher Cho + Cr/Cit ratio is observed in areas of high tumor concentration compared to normal prostate tissue. Figure 2 illustrates the potential of MRS to outline the GTV in a patient with biopsy-proven adenocarcinoma of the prostate. Interestingly, areas of high Gleason score (4 + 3 or above) associated with tumor poor differentiation may be associated with high Cho + Cr/Cit ratio suggesting that MRS may be useful to guide prostate biopsy (4, 5). A high Cho + Cr/Cit ratio is also associated with a large tumor volume and advanced tumor stage (6, 7). As a result, MRS is very accurate to detect high grade tumors within the prostate gland, which may be useful for treatment planning because of the high recurrence rates of these tumors (8). As prostate cancer has a heterogeneous distribution within the prostate gland, MRS is particularly helpful to guide a second biopsy if the initial biopsy was negative among patients with a high PSA level suspicious for prostate cancer (9). MRS can also be used to assess radiotherapy response or recurrence following prostate irradiation. As Cit level decreases following prostate cancer irradiation at a faster rate than Cho or Cr, the Cho level, or Cho/Cr ratio are often used for radiation response.


The potential role of magnetic resonance spectroscopy in image-guided radiotherapy.

Nguyen ML, Willows B, Khan R, Chi A, Kim L, Nour SG, Sroka T, Kerr C, Godinez J, Mills M, Karlsson U, Altdorfer G, Nguyen NP, Jendrasiak G, International Geriatric Radiotherapy Gro - Front Oncol (2014)

This patient has a biopsy-proven adenocarcinoma of the prostate in the magnetic resonance spectroscopy area suspicious for malignancy. Axial (A), Coronal (B), and sagittal (C) high-resolution T2-weighted images. Axial diffusion weighted, b = 2000 (D) and ADC map (E). 1H-spectroscopy demonstrating elevated choline/creatine-to-citrate ratio (F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4017160&req=5

Figure 2: This patient has a biopsy-proven adenocarcinoma of the prostate in the magnetic resonance spectroscopy area suspicious for malignancy. Axial (A), Coronal (B), and sagittal (C) high-resolution T2-weighted images. Axial diffusion weighted, b = 2000 (D) and ADC map (E). 1H-spectroscopy demonstrating elevated choline/creatine-to-citrate ratio (F).
Mentions: Magnetic resonance spectroscopy is particularly helpful to distinguish radiation injury from tumor recurrence after radiotherapy as both may have similar magnetic resonance imaging (MRI) appearances (1). Decreased in Cho, NAA, and Cr are usually observed with radiation injury and high Cho/NAA ratio is suggestive of tumor recurrence (2). In the prostate, Citrate (Cit) is produced by the normal prostate epithelium. The prostate has a high concentration of mitochondrial Zinc (Zn), which inhibits aconitase, the first enzyme of the Krebs cycle, which normally converts citrate to isocitrate leading to a high concentration of citrate in the prostatic epithelium (3). Cit is often decreased in area of prostate adenocarcinoma because of the low Zn concentration. High Cho and Cr are also observed in tumor areas because of cancer cells proliferation. Thus, higher Cho + Cr/Cit ratio is observed in areas of high tumor concentration compared to normal prostate tissue. Figure 2 illustrates the potential of MRS to outline the GTV in a patient with biopsy-proven adenocarcinoma of the prostate. Interestingly, areas of high Gleason score (4 + 3 or above) associated with tumor poor differentiation may be associated with high Cho + Cr/Cit ratio suggesting that MRS may be useful to guide prostate biopsy (4, 5). A high Cho + Cr/Cit ratio is also associated with a large tumor volume and advanced tumor stage (6, 7). As a result, MRS is very accurate to detect high grade tumors within the prostate gland, which may be useful for treatment planning because of the high recurrence rates of these tumors (8). As prostate cancer has a heterogeneous distribution within the prostate gland, MRS is particularly helpful to guide a second biopsy if the initial biopsy was negative among patients with a high PSA level suspicious for prostate cancer (9). MRS can also be used to assess radiotherapy response or recurrence following prostate irradiation. As Cit level decreases following prostate cancer irradiation at a faster rate than Cho or Cr, the Cho level, or Cho/Cr ratio are often used for radiation response.

Bottom Line: Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues.Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe.Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Stanford University , Palo Alto, CA , USA.

ABSTRACT
Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues. The ability of MRS to diagnose areas of high metabolic activity linked to tumor cell proliferation is particularly useful for radiotherapy treatment planning because of better gross tumor volume (GTV) delineation. The GTV may be targeted with higher radiation dose, potentially improving local control without excessive irradiation to the normal adjacent tissues. Prostate cancer and glioblastoma multiforme (GBM) are two tumor models that are associated with a heterogeneous tumor distribution. Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe. Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

No MeSH data available.


Related in: MedlinePlus