For the detection of prostate cancer (PCa) in patients with elevated PSA levels, and who also have a suspicious digital rectal examination, the first-line biopsy method has been transrectal ultrasound biopsy. The limitation of this technique is that there are a higher number of false-negatives due to insufficient sampling of the prostate. Therefore, the first part of the thesis focuses on an alternative technique to overcome these limitations. In patients in whom PCa was suspected, an in-bore MR-guided prostate biopsy (MRGB) was performed. The purpose was to evaluate the diagnostic accuracy and to compare our results to those reported in the literature. In our patient cohort of 41 patients, 11 new PCa were found. These results were slightly lower compared to those in the literature, but, even more important in those patients with a negative MRGB, no new PCa was found during the follow-up period. This suggests that MRGB is a reliable diagnostic tool with a high diagnostic accuracy. With the establishment of prostate MRI in the clinical routine, the question was raised about which MRI parameters should be included for adequate local detection and staging of PCa. The second study included in this thesis deals with the additional value of magnetic resonance spectroscopy imaging (MRSI) in the examination protocol. MRSI is a time-consuming parameter in the MRI protocol. The additional benefit of MRSI has been controversially discussed. In our study, we compared the diagnostic accuracy of a sum score that included three MRI parameters (T2w, DCE, and DWI) versus a sum score with four parameters (additional MRSI). We also evaluated the performance of each score in predicting the Gleason grade. The results of the study showed that a shorter protocol without MRSI at 3Tesla(T) had the same diagnostic accuracy and had good potential for predicting the Gleason score. In 2012, the European Society for Urogenital Radiology published the first version of the prostate imaging reporting and data system (PI-RADS). The guidelines were designed to help standardize the reporting of prostate MRI. To further improve the reporting, a new version, the PIRADS v2, was published 2015. The next study included in Chapter 3 describes a head-to-head comparison of both versions, including inter-reader agreement for both versions to demonstrate the reproducibility. In that study, we evaluated the overall performance of both versions for the detection of PCa, and included a subtype analysis for the peripheral zone (PZ) and the transition zone (TZ) of the prostate. The results showed that the new version was more accurate for the detection of PCa in the TZ. In the PZ, v1 outperformed v2. The reproducibility was almost perfect for both versions. To provide insight into the tumor biology of PCa, the role of positron emission tomography (PET) in combination with MRI has not yet been fully exploited. The next study investigated the feasibility of fused multiparametric [11C]acetate PET-MRI (MP [11C]acetate PET-MRI) to investigate the value of MRI and PET parameters for primary PCa detection and local and distant staging. The results indicated that MP [11C]acetate PET-MRI was feasible and provided background information consistent with the hallmarks of cancer. For the local staging of PCa, the combination of the MRI-derived parameters, T2w and DWI, achieved the highest diagnostic accuracy. The additional benefit of PET was in the distant staging, and the identification of extra metastases not seen with MRI alone. The last chapter of my PhD thesis focuses on patients with biochemical recurrence after radical prostatectomy, due to PCa, in whom bone metastases are suspected. All included patients underwent [11C]acetate PET and bone scintigraphy. In our clinical study, [11C]acetate PET was a reliable tool for the detection of recurrence and especially for the detection of bone metastases. The performance of [11C]acetate PET was equivalent to that of bone scintigraphy.