Early monitoring of external radiation therapy by [18F]-fluoromethylcholine positron emission tomography and 3-T proton magnetic resonance spectroscopy: an experimental study in a rodent rhabdomyosarcoma model

Value of FDG PET/CT in Patient Management and Outcome of Skeletal and Soft Tissue Sarcomas

Fluorodeoxyglucose (FDG)-PET/computed tomography (CT) has been increasingly used in bone and soft tissue sarcomas and provides advantages in the initial tumor staging, tumor grading, therapy assessment, and recurrence detection. FDG-PET/CT metabolic parameters are reliable predictors of survival in sarcomas and could be implemented in risk stratification models along with other prognostic factors in these patients.

Pushing the limits of radiation therapy for prostate cancer: where do we go next?

There have been significant advancements in the quality and precision of radiation therapy (RT) for prostate cancer over the past two decades. The development and implementation of intensity-modulated radiation therapy has allowed for RT dose-escalation without parallel increases in treatment morbidity. Moreover, integration of androgen deprivation therapy with definitive RT has led to improvements in outcomes for certain subgroups of prostate cancer patients. In this review, we highlight several ongoing and developing technical advances that hold promise for further optimizing RT care, including proton beam therapy, inter- and intra-fractional image-guided dose-delivery, methods for improved target volume definition, and development of techniques for safely performing hypofractionation and stereotactic body radiotherapy. We also discuss the importance of investigating the potential benefit of integrating novel systemic therapies with prostate RT to further improve outcomes for patients with locally advanced prostate cancer.

Enhanced choline metabolism in a rodent rhabdomyosarcoma model: correlation between RT-PCR and translational 3 T H-MRS

PURPOSE

To investigate which transmembrane choline transporters and intracellular choline kinases play a prominent role at gene expression level in the rise of the total choline (tCho) peak at proton MR spectra in a rodent rhabdomyosarcoma model.

MATERIALS AND METHODS

Twenty-two rats bearing grafted bilateral syngenic rhabdomyosarcoma were examined on a clinical 3 T MR system. Total choline concentration was measured from proton MR spectra using cubic centimeter volumes of interest (VOIs) located contiguously along the greater axis of the tumour. After euthanasia, cubic centimetre tissue specimens corresponding to Proton magnetic resonance spectroscopy (H-MRS) VOIs were frozen in liquid nitrogen. Out of 89 H-MRS voxels, only 39 with a corresponding tissue specimen suitable for biochemical processing were included in the analysis. RNA was extracted from all the 39 samples and reverse-transcribed into cDNA. Choline kinase α and β gene expression as well as genes of the transmembrane transporters OCT1, OCT2, OCT3, CTL1, CTL3, CTL4 and CHT1 were studied using reverse transcriptase polymerase chain reaction. The expression level of each gene (ΔCt), was normalized referred to that of the RPL19 gene. The Spearman rank correlation coefficient was used to analyse variables.

RESULTS

There was no overexpression of genes coding for kinases; however, significant correlation was observed between kinase α sub-type and the tCho peak (P=.002; r=0.51). OCT1 was the most overexpressed transporter gene. Less overexpressed CTL1 gene was significantly correlated with the tCho peak (P=.02; r=0.38).

CONCLUSION

Choline transporters seem to play a predominant role in the increase in total choline concentration at the gene expression level in our model.