Oligometastases in prostate cancer : Metabolic response in follow-up PSMA-PET-CTs after hypofractionated IGRT.

BACKGROUND: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMAPET/CT) is a new and evolving diagnostic method in prostate cancer with special impact on treatment planning in image-guided radiotherapy (IGRT). Initial results of metabolic response in repeated PSMA PET/CTs after hypofractionated IGRT for metastatic lesions are reported here. MATERIALS AND METHODS: Of 280 patients investigated with 68Ga-PSMA PET/CT in the period from 01/2014 through 12/2016 in the authors' department, patients were selected according to the following criteria: oligometastatic disease at initial PSMA PET/CT defined as not more than five metastatic lesions, hypofractionated IGRT to all lesions, no systemic therapy in the last 6 months and during follow-up, and at least one follow-up PSMA PET after radiotherapy. Radiotherapy was administered to all PSMA PET-detected lesions (CTV = PET-GTV + 1 to 2 mm), mostly with 35 Gy in five fractions (one lesion with four fractions of 7 Gy due to dose constraints, two lymph nodes with 50 Gy in 25 fractions to an extended volume plus a boost of 7 Gy × 2 to the PET-positive volume). Metabolic response of irradiated lesions was evaluated on repeated PSMA PET/CTs according to PERCIST criteria. Five patients with a total number of 12 PSMA PETs matched the criteria. Patients received radiotherapy to all PET-positive lesions and had at least one (in one case three) follow-up PSMA PET examinations after radiotherapy with an interval to the first PET of 2-15 months; the median follow-up for all patients was 11 months. RESULTS: The mean prostate-specific antigen (PSA) values at the time of examination were 8.9 ± 8.5 ng/ml (median 3.3 ng/ml, range 0.17-21.8 ng/ml). A total number of 18 metastatic deposits were detected. The PET-positive tumor volume was 5.9 ± 13.3 cm3 (median 1.25 cm3). The mean standardized uptake value (mean SUVmax) of the 18 metastatic lesions decreased from 19.9 ± 23.3 (mean ± SD) prior to RT to 5.4 ± 4.6 at post-radiotherapy PSMA PET/CT. Using PERCIST criteria, 14 lesions (78%) showed a metabolic response in PSMA PET with a reduction of SUV of at least 30%, as well as a significant decrease in lesion size; in seven of these lesions, no uptake of 68Ga-PSMA was detectable. In follow-up PET scans, only two lesions showed metabolic progression with an increase in SUVmax yielding a local progression-free survival of 88% after 1 year. There was a correlation between the time interval after radiotherapy (median 3 months, range 1-9 months) and response (p = 0.04) with better metabolic response after longer follow-up. CONCLUSIONS: Preliminary results of this study show high metabolic response rates of PSMA PET-positive metastatic lesions after hypofractionated radiotherapy in follow-up PSMA PET with promising local control rates. An interval of several months may be required to fully estimate the efficacy of radiotherapy in control PSMA PET.

106Ruthenium eye plaque brachytherapy in the management of medium sized uveal melanoma.

BACKGROUND: To evaluate 106Ruthenium Brachytherapy in management of medium sized uveal melanoma, with emphasis on 5-year outcome and toxicity. METHODS: From April 2007 to October 2015, 39 patients with medium sized uveal melanoma were treated with 106 Ru eye plaques brachytherapy. At the time of diagnosis, the mean tumor depth was 3.7 mm (±SD:1.6 mm). The mean dose at the tumor apex was 141.4 Gy (± SD: 12.1 Gy) and 557.7 Gy (± SD: 257.3 Gy) to the sclera. RESULTS: Mean follow-up was 69.5 months (± SD: 53.8 months). Thirty-four patients (87.1%) remained free of recurrence. Twenty-six patients (66.7%) demonstrated a complete tumor regression after a median period of 12 months (3-60 mon.). By the final examination, the visual acuity of 26 patients (66.7%) was better than 20/200, and 12 patients (30.7%) had a visual acuity better than 20/40. Retinopathy was detected in 11 patients (28.2%). After treatments only one patient (5.1%) had active vascular changes by the last examination. Moderate optic neuropathy was observed in 4 patients (10.3%). Cataract development was diagnosed in 21 patients (53.8%), and 16 patients (41%) had bilateral cataract development. Special emphasis was made on patients with larger tumors. Twelve out of the 39 patients had a tumor with a depth of 5 mm or more. There was no significant difference in local control or in side effects between both groups observed. CONCLUSIONS: Our study proved 106Ru -brachytherapy to be an excellent treatment option with regard to tumor control and preservation of the visual acuity in well-selected patients. Our data suggested that this treatment is also suitable for tumors with a depth of more than 5 mm.

Efficacy and the toxicity of the interstitial high-dose-rate brachytherapy in the management of recurrent keloids: 5-year outcomes.

PURPOSE: Recurring keloids are a clinical challenge. Interdisciplinary treatments are required in most cases. Owing to the wide variety of concepts, the optimal treatment regime remains unclear. Our clinic established a protocol of perioperative interstitial high-dose-rate brachytherapy with three fractions of 6 Gy and achieved an excellent 2-year local control rate of 94% (In search of the optimal treatment of keloids: Report of a series and a review of the literature). This report is an update on our long-term results of prospective study. Twenty-nine patients were included with a median followup of 5 years. METHODS AND MATERIALS: From 2009 to 2015, 29 patients with 37 recurrent keloids were treated with perioperative interstitial high-dose-rate brachytherapy; 3 patients had been previously treated with adjuvant external beam radiotherapy and presented with recurrences in the pretreated area. Brachytherapy was given in three fractions with a single dose of 6 Gy in 5-mm tissue depth and covered the scar in total length. Followup visits were scheduled at 6 weeks, 3 months, 6 months, 1 year, and annually thereafter. Therapeutic outcome was assessed in terms of recurrence, acute and late complications, and cosmetic results. RESULTS: No procedure-related complications occurred. Improvement of keloid-related symptoms was noticed in all patients after treatment. After a median followup of 49.7 months (range: 7.9-91.9 months), three keloid recurrences and two hypertrophied scars were observed. CONCLUSIONS: Our results suggest that brachytherapy may be advantageous in the management of high-risk keloids, even after failure of external beam radiotherapy and other treatment procedures. Our three-fraction treatment schedule reduces the treatment period to 2 days and is therefore convenient for the patients.

Interstitial high-dose-rate brachytherapy as salvage treatment for locally recurrent prostate cancer after definitive radiation therapy: Toxicity and 5-year outcome.

PURPOSE: We report our results with interstitial high-dose-rate brachytherapy (HDR-BT) as a salvage therapy option after external beam therapy with or without BT. Emphasis was put on toxicity and 5-year outcome. METHODS AND MATERIALS: From 2003 to 2011, 29 patients with local failure after previous radiotherapy for prostate cancer were treated with salvage interstitial HDR-BT. The diagnosis of local recurrence was made on the basis of choline positron emission tomography. Salvage HDR-BT was given in three fractions with a single dose of 10 Gy per fraction and weekly. The target volume covered the peripheral zone of the prostate and the positron emission tomography-positive area. Acute and late toxicities were documented according to common terminology criteria for adverse events (CTCAE v 4.0). RESULTS: Twenty-two patients with minimum followup of 60 months were analyzed. The 5-year overall survival was 95.5% with a disease-specific survival of 100%. The 5-year biochemical control was 45%. Late grade 2 gastrointestinal toxicities were observed in two patients (9%). No grade 3 or higher gastrointestinal late toxicities were observed. Urinary incontinence found in 2 patients (9%) and grade 2 obstruction of urinary tract occurred in one patient (4%). CONCLUSIONS: Interstitial HDR-BT was feasible and effective in the treatment of locally recurrent prostate cancer after definitive radiotherapy. The long-term toxicity was low and acceptable.

New workflows and algorithms of bone scintigraphy based on SPECT-CT.

Gold standard bone scintigraphy workflow contains acquisition of planar anterior and posterior images and if necessary, additional SPECTs as well. Planar acquisitions are time consuming and not enough for accurately locating hotspots. Current paper proposes a novel workflow for fast whole body bone SPECT scintigraphy. We present a novel stitching method to generate a whole body SPECT based on the SPECT projections. Our stitching method is performed on the projection series not on the reconstructed SPECTs, thus stitching artifacts are greatly reduced. Our workflow does not require any anterior-posterior image pairs, since these images are derived from the reconstructed whole body SPECT automatically. Our stitching method has been validated on real clinical data performed by medical physicians. Results show that our method is very effective for whole body SPECT generations leaving no signs of artifacts. Our workflow required overall 16 minutes to acquire a whole body SPECT which is comparable to the 60 minutes acquisition time required for gold standard techniques including planar images and additional SPECT acquisitions.

An extended registration framework for the triple registration of IBZM SPECT, DATSCAN SPECT and MRI brain images to support the evaluation of brain dopamine receptor scintigraphies.

An extended registration model is presented to register medical image triples acquired for brain dopamine receptor scintigraphies. The model operates with rigid and nonlinear transformations in parallel, where all transformation parameters are optimized by one optimization method. The concept of the transformation-sampling-similarity measurement minimizes the memory usage of a real implementation. A partial-fine sampling method is proposed to decrease the processing time of the registration. Real medical data was collected to compare our method with well-known prior ones. The first tests show that the model outperforms the classic registration methods in both speed and accuracy.

Automated lymph node detection and classification on breast and prostate cancer SPECT-CT images.

We present a novel detection and classification method to process SPECT-CT images representing breast and prostate lymph nodes. Lymph nodes are those nodes that are near the primer tumor and may become cancerous in time, hence their early detection is a key factor for the successful treatment of the patient. Prior methods focus on the visual aid to manually detect the lymph nodes which still makes the process time-consuming. Other solutions segment the lymph nodes only on CT, where the small lymph nodes may not be located accurately. Our solution processed both SPECT and CT data to provide an accurate classification of all SPECT hot spots. The method has been validated on a huge amount of medical data. Results show that our method is a very effective tool to support physicians working with related images in the field of nuclear medicine.