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Since 4D-MRI is inadequate to capture dynamic respiratory variations, real-time cinematographic (cine) MRI is actively used in MR-guided radiotherapy (MRgRT) for tumor motion evaluation, delineation, and tracking. However, most radiotherapy imaging platforms do not support the format of cine MRI from clinical MRI systems. This study developed an institutional solution of clinical cine MRI for tumor motion evaluation in radiotherapy applications.Cine MRI manipulation software (called Cine Viewer) was developed within a commercial Treatment Planning System (TPS). It consists of (1) single/orthogonal viewers, (2) display controllers, (3) measurement grids/markers, and (4) manual contouring tools.The institutional solution of clinical cine MRI incorporated with radiotherapy application was assessed through case presentations (liver cancer). Cine Viewer loaded cine MRIs from 1.5T Philips Ingenia MRI, handling MRI DICOM format. The measurement grids and markers were used to quantify the displacement of anatomical structures in addition to the tumor. The contouring tool was utilized to localize the tumor and surrogates on the designated frame. The stacks of the contours were exhibited to present the ranges of tumor and surrogate motions. For example, the stacks of the tumor contours from case-1 were used to determine the ranges of tumor motions (∼8.17 mm on the x-direction [AP-direction] and ∼14 mm on the y-direction [SI-direction]). In addition, the patterns of the displacement of the contours over frames were analyzed and reported using in-house software. In the case-1 review, the tumor was displaced from +146.0 mm on the x-direction and +125.0 mm on the y-direction from the ROI of the abdominal surface.We demonstrated the institutional solution of clinical cine MRI in radiotherapy. The proposed tools can streamline the utilization of cine MRI for tumor motion evaluation using Eclipse for treatment planning.

Lattice stereotactic body radiation therapy (SBRT) is a form of spatially fractionated radiation therapy (SFRT) using SBRT methods. This study reports clinical dosimetric endpoints achieved for Lattice SBRT plans delivering 20 Gy in 5 fractions to the periphery of a tumor with a simultaneous integrated boost (SIB) of 66.7 Gy, as part of a prospective Phase I clinical trial (NCT04133415). Additionally, it updates previously reported planning and delivery techniques based on extended experience with a broader patient population.Patients were enrolled on a single-arm phase I trial conducted between November 2019 and August 2020. Eligibility was restricted to tumors4.5 cm in the largest dimension. Characteristic SFRT dose gradients were achieved using a lattice of 1.5 cm diameter spheres spaced within the GTV in a regular pattern, with peak-to-valley dose varying from 66.7 Gy to 20 Gy within 1.5 cm. Organ-at-risk (OAR) sparing followed AAPM TG101 recommendations for 5-fraction SBRT.Twenty patients (22 plans) were enrolled on study, with one additional plan treated off study. All OAR and target coverage planning objectives were achieved, with the exception of a single small bronchus. Conformity of the 20 Gy isodose line significantly improved over the course of the study. The majority (85.2%) of treatment fractions were delivered in a 30 minutes timeslot, with 4 (3.5%) exceeding a total treatment time of 40 minutes.Lattice SBRT planning techniques produce consistent and efficient treatment plans. Refined techniques described here further improve the quality of the planning technique.

Purpose To evaluate serum testosterone and the incidence of biochemical hypogonadism in men treated with intensity modulated radiation therapy (IMRT) for prostate cancer. Methods and materials Serum testosterone was evaluated prospectively in 51 men at pretreatment and at 6-month time points for 2 years posttreatment with IMRT for prostate cancer. Forty-one patients (80%) were treated with definitive intent and 10 patients with postprostatectomy radiation to median total doses of 7380 cGy and 6480 cGy, respectively. No patients received hormone therapy within 12 months of any serum testosterone value. Biochemical hypogonadism was defined as a total serum testosterone level ≤300 ng/dL. Incidental testicular dose was calculated using planning software when computed tomography information was available (n = 21) and using a published method of estimation when not available (n = 24), and was available for 45 patients. Results A statistically significant decrease in testosterone, though small in magnitude, was seen at 6 months after completion of therapy, with no significant difference by 1 year after completion of therapy. There was no increase in biochemical hypogonadism after IMRT. Below-normal pretreatment testosterone was not associated with a transient decrease. Estimated cumulative testicular dose, including dose from daily imaging, was not associated with a change in testosterone, nor was radiation therapy prescription dose or treatment intent (postoperative vs definitive). Conclusions The mild transient decrease in serum testosterone following IMRT monotherapy for prostate cancer is not associated with new biochemical hypogonadism.