Discordance between prostate MRI and PSMA-PET/CT: the next big challenge for primary prostate tumor assessment?

Objectives: An increasing number of patients with prostate cancer (PCa) undergo assessment with magnetic resonance imaging (MRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT). This offers comprehensive multimodality staging but can lead to discrepancies. The objective was to assess the rates and types of discordance between MRI and PSMA-PET/CT for primary PCa assessment.

Feasibility of quantitative relaxometry for prostate target localization and response assessment in magnetic resonance-guided online adaptive stereotactic body radiotherapy.

Purpose: Multiparametric magnetic resonance imaging (MRI) is known to provide predictors for malignancy and treatment outcome. The inclusion of these datasets in workflows for online adaptive planning remains under investigation. We demonstrate the feasibility of longitudinal relaxometry in online MR-guided adaptive stereotactic body radiotherapy (SBRT) to the prostate and dominant intra-prostatic lesion (DIL).

Commissioning and implementation of a pencil-beam algorithm with a Lorentz correction as a secondary dose calculation algorithm for an Elekta Unity 1.5T MR linear accelerator.

Purpose: To commission a beam model in ClearCalc (Radformation Inc.) for use as a secondary dose calculation algorithm and to implement its use into an adaptive workflow for an MR-linear accelerator.

Methods: A beam model was developed using commissioning data for an Elekta Unity MR-linear accelerator and entered into ClearCalc.

Depth of Hydrogel Spacer Rectal Wall Infiltration Was Not Associated With Rectal Toxicity: Results From a Randomized Prospective Trial.

Purpose: Rectal spacers have gained popularity as a dose-sparing material for prostate cancer radiation therapy (RT). However, the procedure can be associated with unintended rectal wall infiltration (RWI) of the spacer gel. We therefore classified RWI severity as a function of depth and explored its association with rectal toxicity using a data set from prostate cancer patients treated with RT on a prospective randomized clinical trial (RCT).

Reduction of Postradiation Therapy Urinary Toxicity Via Intrafractional Megavoltage-Kilovoltage Prostate Location Monitoring.

Purpose: We hypothesized that an in-house developed system using megavoltage and kilovoltage image guidance (MKIG) to ensure correct prostate positioning during stereotactic body radiation therapy (SBRT) could potentially avoid unwanted doses to nontarget tissues, leading to reduced toxicities.

Methods And Materials: We built a 3-dimensional MKIG platform that accurately tracks prostate implanted fiducials in real time and clinically translated the system to replace a commercial approach, intrafraction motion review (IMR), which only tracks fiducials in the 2-dimensional kilovoltage views. From 2017 to 2019, 150 patients with prostate cancer were treated with SBRT and monitored using MKIG.