The aim was to identify preimplant factors affecting postimplant prostate volume and the increase in prostate volume after transperineal interstitial prostate brachytherapy with 125I free seeds.
We reviewed the records of 180 patients who underwent prostate brachytherapy with 125I free seeds for clinical T1/T2 prostate cancer. Eighty-one (45%) of the 180 patients underwent neoadjuvant hormonal therapy. No patient received supplemental external beam radiotherapy. Postimplant computed tomography was undertaken, and postimplant dosimetric analysis was performed. Univariate and multivariate analyses were performed to identify preimplant factors affecting postimplant prostate volume by computed tomography and the increase in prostate volume after implantation.
Preimplant prostate volume by transrectal ultrasound, serum prostate-specific antigen, number of needles, and number of seeds implanted were significantly correlated with postimplant prostate volume by computed tomography. The increase in prostate volume after implantation was significantly higher in patients with neoadjuvant hormonal therapy than in those without. Preimplant prostate volume by transrectal ultrasound, number of needles, and number of seeds implanted were significantly correlated with the increase in prostate volume after implantation. Stepwise multiple linear regression analysis showed that preimplant prostate volume by transrectal ultrasound and neoadjuvant hormonal therapy were significant independent factors affecting both postimplant prostate volume by computed tomography and the increase in prostate volume after implantation.
The results of the present study show that preimplant prostate volume by transrectal ultrasound and neoadjuvant hormonal therapy are significant preimplant factors affecting both postimplant prostate volume by computed tomography and the increase in prostate volume after implantation.
Prostate brachytherapy is a treatment for prostate cancer using radioactive seeds that are permanently implanted in the prostate. The treatment success depends on adequate coverage of the target gland with a therapeutic dose, while sparing the surrounding tissue. Since seed implantation is performed under transrectal ultrasound (TRUS) imaging, intraoperative localization of the seeds in ultrasound can provide physicians with dynamic dose assessment and plan modification. However, since all seeds cannot be seen in the ultrasound images, registration between ultrasound and fluoroscopy is a practical solution for intraoperative dosimetry. In this manuscript, we introduce a new image-based nonrigid registration method that obviates the need for manual seed segmentation in TRUS images and compensates for the prostate displacement and deformation due to TRUS probe pressure. First, we filter the ultrasound images for subsequent registration using thresholding and Gaussian blurring. Second, a computationally efficient point-to-volume similarity metric, an affine transformation and an evolutionary optimizer are used in the registration loop. A phantom study showed final registration errors of 0.84 ± 0.45 mm compared to ground truth. In a study on data from 10 patients, the registration algorithm showed overall seed-to-seed errors of 1.7 ± 1.0 mm and 1.5 ± 0.9 mm for rigid and nonrigid registration methods, respectively, performed in approximately 30 seconds per patient.
Prostate Brachytherapy; Registration; Fluoroscopy; Ultrasound
To determine prostate volume (Pvol) changes at 3 different time points during the course of I125 permanent seed brachytherapy (PB). To assess the impact of these changes on acute urinary retention (AUR) and dosimetric outcome.
We analyzed 149 hormone-naïve patients. Measurements of the prostate volume were done using three-dimensional transrectal ultrasound (3D-TRUS) in the operating room before insertion of any needle (V1), after the insertion of 2 fixation needles with a harpoon (V2) and upon completion of the implant (V3). The quality of the implant was analyzed with the D90 (minimum dose in Grays received by 90% of the prostate volume) at day 30.
Mean baseline prostate volume (V1) was 37.4 ± 9.6 cc. A volume increase of >5% was seen in 51% between V1-V2 (mean = 2.5 cc, p < 0.01), in 42% between V2-V3 (mean = 1.9 cc, p < 0.01) and in 71% between V1-V3 (mean = 4.5 cc, p < 0.01). Pvol changes caused by insertion of the fixation needles were not statistically different than those caused by the implant itself (p = 0.23).
In multivariate linear regression analysis, baseline Pvol is predictive of Pvol changes between V2 and V1 and V3 and V1 but not between V3 and V2. The extent of prostate swelling had an influence on D90. An increase of 10% in prostate volume between V1 and V2 results in an increase of D90 at Day 30 by 11.7%. Baseline Pvol (V1) was the only predictor of the duration of urinary retention in both univariate and multivariate (p = 0.04) regression analysis.
A large part of intraoperative swelling occurs already after the insertion of the fixation needles. This early prostate swelling predicts for D90 but not for AUR.
Prostate; Permanent seed brachytherapy; Intra-operative edema
Post-implant dosimetry following prostate seed implantation (PSI) occasionally reveals suboptimal dosimetric coverage of the gland. Published reports of re-implantation techniques have focused on earlier-generation techniques, including preplanned approaches and stranded seeds. The purpose of this case report is to describe a customizable approach to perform corrective re-implantation using loose seeds and intraoperative planning technique.
Material and methods
This case report describes a 63-year-old male with favorable risk prostate adenocarcinoma receiving PSI. Thirty day post-implant dosimetric evaluation revealed suboptimal coverage of the base of the gland. Using guidance from post-implant CT-images and real-time planning, the patient received a corrective re-implantation with intraoperative planning.
Post-implant dosimetry after re-implantation procedure with intraoperative planning yielded improved target volume coverage that achieved standard dosimetric criteria.
Re-implantation as a salvage treatment technique after sub-optimal PSI is a valid treatment option performed with intraoperative real-time planning.
low-dose-rate brachytherapy; prostate cancer; re-implantation; salvage therapy; seeds
Transrectal ultrasound (TRUS) facilitates intra-treatment delineation of the prostate gland (PG) to guide insertion of brachytherapy seeds, but the prostate substructure and apex are not always visible which may make the seed placement sub-optimal. Based on an elastic model of the prostate created from MRI, where the prostate substructure and apex are clearly visible, we use a Bayesian approach to estimate the posterior distribution on deformations that aligns the pre-treatment MRI with intra-treatment TRUS. Without apex information in TRUS, the posterior prediction of the location of the prostate boundary, and the prostate apex boundary in particular, is mainly determined by the pseudo stiffness hyper-parameter of the prior distribution. We estimate the optimal value of the stiffness through likelihood maximization that is sensitive to the accuracy as well as the precision of the posterior prediction at the apex boundary. From a data-set of 10 pre- and intra-treatment prostate images with ground truth delineation of the total PG, 4 cases were used to establish an optimal stiffness hyper-parameter when 15% of the prostate delineation was removed to simulate lack of apex information in TRUS, while the remaining 6 cases were used to cross-validate the registration accuracy and uncertainty over the PG and in the apex.
To investigate whether a longer sagittal view and less movement using a dual sagittal crystal probe (DSCP) for trans rectal ultra sound (TRUS) allow for more accurate online-planning in I-125 permanent implant brachytherapy of the prostate, compared to a single sagittal crystal probe (SSCP).
Material and methods
Between March 2008 and March 2010, 50 patients with prostate cancer were consecutively included in the study. The first 25 of these patients had both their pre- and online-planning based on a single sagittal crystal probe (SSCP). The treatment-plans of the other 25 patients were based on a DSCP TRUS. Three weeks after implantation a post-planning was made based on CT. TRUS online and CT post-plan dose-volume histogram (DVH) parameters, D90 and V100, were compared for both groups. Also, the post-plan DVH parameters of SSCP were compared to DSCP. The possible factors that might influence the post-plan D90 and V100 were analysed using Analysis of Variance (ANOVA).
SSCP and DSCP online mean D90 and V100 were significantly larger than post-plan mean D90 and V100 (P < 0.01). The post-plan mean D90 and mean V100 were both non-significantly larger for SSCP based post-plans compared to DSCP based post plans (P = 0.76 and P = 0.68). ANOVA showed significant impact of prostate volume on the post-plan D90 and V100.
The advantages of the dual sagittal crystal probe did not lead to more accurate online planning by investigating DVH-parameters. The only factor found to have influence on the DVH-parameters was the prostate volume.
prostatic neoplasms; brachytherapy; computer assisted radiotherapy planning; transrectal ultrasound; D90; V100
Background & Purpose
Rectal toxicity is less common after 125I seed implant brachytherapy for prostate cancer, and intraoperative rectal dose-volume constraints (the constraint) is still undetermined in pioneering studies. As our constraint failed to prevent grade 2 or 3 rectal bleeding (bled-pts) in 5.1% of patients, we retrospectively explored another constraint for the prevention of rectal bleeding.
Materials and methods
The study population consisted of 197 patients treated with the brachytherapy as monotherapy using real-time intraoperative transrectal ultrasound (US)-guided treatment at a prescribed dose of 145 Gy. Post-implant dosimetry was performed on Day 1 and Day 30 after implantation using computed tomography (CT) imaging. Rectal bleeding toxicity was classified by CTC-AE ver. 3.0 during a mean 29-month (range, 12-48 months) period after implantation. The differences in rV100s were compared among intraoperative, Day 1 and Day 30 dosimetry, and between that of patients with grade 2 or 3 rectal bleeding (the bled-pts) and of the others (the spared-pts). All patients were divided into groups based on provisional rV100s that were increased stepwise in 0.1-cc increments from 0 to 1.0 cc. The difference in the ratios of the bled-pts to the spared-pts was tested by chi-square tests, and their odds ratios were calculated (bled-OR). All statistical analyses were performed by t-tests.
The mean values of rV100us, rV100CT_1, and rV100CT_30 were 0.31 ± 0.43, 0.22 ± 0.36, and 0.59 ± 0.68 cc, respectively. These values temporarily decreased (p = 0.020) on Day 1 and increased (p = 0.000) on Day 30. There was no significant difference in rV100s between the bled-pts and spared-pts at any time of dosimetry. The maximum bled-OR was identified among patients with an rV100us value above 0.1 cc (p = 0.025; OR = 7.8; 95% CI, 1.4-145.8); an rV100CT_1 value above 0.3 cc (p = 0.014; OR = 16.2; 95% CI, 3.9-110.7), and an rV100CT_30 value above 0.5 cc (p = 0.019; OR = 6.3; 95% CI, 1.5-42.3).
By retrospective analysis exploring rV100 as intraoperative rectal dose-volume thresholds in 125I seed implant brachytherapy for prostate cancer, it is proved that rV100 should be less than 0.1 cc for preventing rectal bleeding.
prostate cancer; brachytherapy; dose-volume histogram
To evaluate the long term effectiveness of transrectal ultrasound (TRUS)-guided permanent radioactive I125 implantation of the prostate for organ confined adenocarcinoma of the prostate compared with historical data of prostatectomy and external beam radiotherapy (EBRT) within a cooperative group setting.
Methods and Materials
Patients accrued to this study had histologically confirmed, locally confined, adenocarcinoma of the prostate clinical stage T1b, T1c, or T2a, no nodal or metastatic disease, prostate specific antigen (PSA) level of ≤ 10 ng/ml and a Gleason score of ≤ 6. All patients underwent TRUS-guided radioactive I125 seed implantation into the prostate. The prescribed dose was 145 Gy to the prostate planning target volume (PTV).
A total of 101 patients from 27 institutions were accrued to this protocol; by design no single institution accrued more than 8 patients. There were 94 eligible patients. The median follow up was 8.1 years (range 0.1 to 9.2 years). After 8 years, 8 patients had protocol-defined biochemical (PSA) failure (cumulative incidence 8.0%), 5 patients had local failure (cumulative incidence 5.5%), and 1 patient had distant failure (cumulative incidence 1.1%; this patient also had biochemical failure and non-prostate cancer related death). The 8-year overall survival (OS) rate was 88%. At last follow up, no patient died of prostate cancer or related toxicities. Three patients had maximum late toxicity of Grade 3 and all were genitourinary (GU). There were no Grade 4 or 5 toxicities observed.
The long term results of this clinical trial have demonstrated that this kind of trial can be successfully completed through the RTOG and that results in terms of biochemical failure and toxicity compare very favorably with other brachytherapy published series as well as surgical and external beam radiotherapy series. Additionally, the prospective, multi-centered design highlights the probably generalizability of the outcomes.
Prostate; brachytherapy; low dose rate (LDR)
To report the clinical outcome of high dose rate brachytherapy as sole treatment for clinically localised prostate cancer.
Between March 2004 and January 2008, a total of 351 consecutive patients with clinically localised prostate cancer were treated with transrectal ultrasound guided high dose rate brachytherapy. The prescribed dose was 38.0 Gy in four fractions (two implants of two fractions each of 9.5 Gy with an interval of 14 days between the implants) delivered to an intraoperative transrectal ultrasound real-time defined planning treatment volume. Biochemical failure was defined according to the Phoenix Consensus and toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 3.
The median follow-up time was 59.3 months. The 36 and 60 month biochemical control and metastasis-free survival rates were respectively 98%, 94% and 99%, 98%. Toxicity was scored per event with 4.8% acute Grade 3 genitourinary and no acute Grade 3 gastrointestinal toxicity. Late Grade 3 genitourinary and gastrointestinal toxicity were respectively 3.4% and 1.4%. No instances of Grade 4 or greater acute or late adverse events were reported.
Our results confirm high dose rate brachytherapy as safe and effective monotherapy for clinically organ-confined prostate cancer.
Prostate cancer; Brachytherapy; High dose rate; Iridium; Monotherapy
To perform a dosimetric comparison between a pre-planned technique and a pre-plan based intraoperative technique in prostate cancer patients treated with I-125 permanent seed implantation.
Material and methods
Thirty patients were treated with I-125 permanent seed implantation using TRUS guidance. The first 15 of these patients (Arm A) were treated with a pre-planned technique using ultrasound images acquired prior to seed implantation. To evaluate the reproducibility of the prostate volume, ultrasound images were also acquired during the procedure in the operating room (OR). A surface registration was applied to determine the 6D offset between different image sets in arm A. The remaining 15 patients (Arm B) were planned by putting the pre-plan on the intraoperative ultrasound image and then re-optimizing the seed locations with minimal changes to the pre-plan needle locations. Post implant dosimetric analyses included comparisons of V100(prostate), D90(prostate) and V100(rectum).
In Arm A, the 6D offsets between the two image sets were θx=−1.4±4.3; θy=−1.7±2.6; θz=−0.5±2.6; X=0.5±1.8 mm; Y=−1.3±−3.5 mm; Z=−1.6±2.2 mm. These differences alone degraded V100 by 6.4% and D90 by 9.3% in the pre-plan, respectively. Comparing Arm A with Arm B, the pre-plan based intraoperative optimization of seed locations used in the plans for patients in Arm B improved the V100 and D90 in their post-implant studies by 4.0% and 5.7%, respectively. This was achieved without significantly increasing the rectal dose (V100(rectum)).
We have progressively moved prostate seed implantation from a pre-planned technique to a pre-plan based intraoperative technique. In addition to reserving the advantage of cost-effective seed ordering and efficient OR implantation, our intraoperative technique demonstrates increased accuracy and precision compared to the pre-planned technique.
pre-plan; intraoperative planning; seed implant; prostate cancer
To evaluate the outcomes of patients presenting with cancer at the base of the prostate after brachytherapy as monotherapy.
Material and methods
We retrospectively reviewed the medical records of all patients who had undergone transperineal ultrasound-guided implantation with 125I or 103Pd seeds as monotherapy between March 1998 and December 2006, at our institution. A minimum follow-up interval of 2 years was required for inclusion in our analysis. Dosimetry was assessed using computed tomography 30 days after the implant. Treatment failure was defined as the appearance of biopsy-proved tumor after seed implantation, radiographic evidence of metastases, receipt of salvage therapy, or elevation of the prostate-specific antigen level beyond the nadir value plus 2 ng/mL.
With a median follow-up interval of 89 months (range 25–128 months), all 52 of the identified patients had no evidence of disease progression or biochemical failure. The mean number of cores sampled at the prostate base was 2.84 (median 2); Gleason scores assigned at central review were 6-8 in all patients. Of the 30 patients (58%) for whom dosimetric data were available at day 30, the median V100 values of the right and left base were 92.0% and 93.5%, respectively, and the median D90 values of the right and left base were 148 Gy and 151 Gy, respectively.
Permanent prostate brachytherapy as monotherapy results in a high probability of disease-free survival for men with cancer at the base of the prostate.
prostate cancer; monotherapy; sector analysis
We investigated the usefulness of the fusion image created by transrectal ultrasonography (TRUS) and large-bore computed tomography (CT) for predicting pubic arch interference (PAI) during prostate seed brachytherapy. The TRUS volume study was performed in 21 patients, followed by large-bore computed tomography of patients in the lithotomy position. Then, we created TRUS-CT fusion images using a radiation planning treatment system. TRUS images in which the prostate outline was the largest were overlaid on CT images with the narrowest pubic arch. PAI was estimated in the right and left arch separately and classified to three grades: no PAI, PAI positive within 5 mm and PAI of >5 mm. If the estimated PAI was more than 5 mm on at least one side of the arch, we judged there to be a significant PAI. Brachytherapy was performed in 18 patients who were evaluated as not having significant PAI on TRUS. Intra-operative PAI was observed in one case, which was also detected with a fusion image. On the other hand, intra-operative PAI was not observed in one case that had been evaluated as having significant PAI with a fusion image. In the remaining three patients, TRUS suggested the presence of significant PAI, which was also confirmed by a fusion image. Intra-operative PAI could be predicted by TRUS-CT fusion imaging, even when it was undetectable by TRUS. Although improvement of the reproducibility of the patients’ position to avoid false-positive cases is warranted, TRUS-CT fusion imaging has the possibility that the uncertainty of TRUS can be supplemented.
prostate cancer; brachytherapy; seed implantation; pubic arch interference; fusion image
To evaluate in a multicenter setting the ability of centers to perform pre-implant permanent prostate brachytherapy planning, fulfilling dosimetric goals and constraints based on the Groupe de Curiethérapie-European Society for Radiotherapy and Oncology guidelines in the setting of implantation after prior prostate transurethral resection (TURP).
Material and methods
A reference transrectal ultrasound image set of the prostate gland from a patient who had undergone TURP was used. Contouring of the prostate, clinical target volume and organs at risk was performed by the coordinating center. Goals and constraints regarding the dosimetry were defined.
Seventeen of twenty-five centers invited to participate were able to import the Digital Imaging and Communications in Medicine-images into their planning computer and plan the implant using the defined guidelines. All centers were able to plan treatment, and achieve the recommended objectives and constraints. However, sector analysis has shown a risk of under-dosage in the anterior part of the prostate.
Correct pre-implantation planning with adherence to protocol guidelines and in compliance with defined dosimetric constraints seems feasible in a post-TURP setting, at least on a theoretical basis. A prospective study evaluating the outcome of prostate brachytherapy performed after TURP can therefore be undertaken with an expectation of a correct dosimetry in the multicenter setting.
brachytherapy; permanent seed implant; prostate cancer; transurethral resection; TURP
In prostate brachytherapy, a transrectal ultrasound (TRUS) will show the prostate boundary but not all the implanted seeds, while fluoroscopy will show all the seeds clearly but not the boundary. We propose an intensity-based registration between TRUS images and the implant reconstructed from uoroscopy as a means of achieving accurate intra-operative dosimetry. The TRUS images are first filtered and compounded, and then registered to the uoroscopy model via mutual information. A training phantom was implanted with 48 seeds and imaged. Various ultrasound filtering techniques were analyzed, and the best results were achieved with the Bayesian combination of adaptive thresholding, phase congruency, and compensation for the non-uniform ultrasound beam profile in the elevation and lateral directions. The average registration error between corresponding seeds relative to the ground truth was 0.78 mm. The effect of false positives and false negatives in ultrasound were investigated by masking true seeds in the uoroscopy volume or adding false seeds. The registration error remained below 1.01 mm when the false positive rate was 31%, and 0.96 mm when the false negative rate was 31%. This fully automated method delivers excellent registration accuracy and robustness in phantom studies, and promises to demonstrate clinically adequate performance on human data as well. Keywords: Prostate brachytherapy, Ultrasound, Fluoroscopy, Registration.
Prostate cancer foci have a characteristic feature in magnetic resonance imaging (MRI). We aimed to assess the clinical value of MRI before prostate biopsy in prostate cancer detection.
Materials and Methods
From March 2009 to June 2010, 154 patients were enrolled in this study. A total of 51 patients with a clinical suspicion of prostate cancer underwent prostate MRI by a 3T scanner before transrectal ultrasound (TRUS)-guided biopsies. A total of 103 patients with a clinical suspicion of prostate cancer underwent prostate MRI after biopsies. The sensitivity, specificity, and positive predictive value (PPV) were evaluated. In addition, tumor location of pathologic findings and ADC mapping on MRI were matched and compared.
The sensitivity of MRI before and after biopsy was 84.8% and 92.4%, respectively. The PPV of MRI before and after biopsy was 75.7% and 92.4%, respectively. The MRI location match percentage before and after biopsy was 89.3% and 94.1%, respectively.
Compared with other previous reports, our results show that the prostate cancer detection sensitivity of MRI is on the rise. Furthermore, MRI before prostate biopsy can provide more information by which to identify prostate cancer during prostate biopsy and thus reduce the false-negative rate.
Biopsy; MRI; Prostate cancer
There is a 0.16% chance of a rectourethral fistula after prostate brachytherapy monotherapy using Palladium-103 or Iodine-125 implants. We present an unusual case report of a rectourethral fistula following brachyradiotherapy monotherapy for prostate adenocarcinoma. It was also associated with unusual management of the fistula.
A 58-year-old Caucasian man underwent brachyradiotherapy monotherapy as definitive treatment for verified intracapsular prostate adenocarcinoma receiving 56 Iodine-125 implants using a transrectal ultrasound-guided technique. The patient started to complain of severe perineal pain and mild rectal bleeding 15Â months after brachyradiotherapy. A biopsy of mucosa of his anterior rectal wall was performed. A moderate sized rectourethral fistula was confirmed 23Â months after implantation of Iodine-125 seeds. Laparoscopic sigmoidostomy and suprapubic cystostomy were then performed. Long-term cortisone applications in combination with 30 sessions of hyperbaric oxygen therapy, and antibacterial therapies were initiated due to necrotic infection. A gracilis muscle interposition to create a partition between the patient's rectum and urethra in conjunction with primary rectal repair but without urethral repair were performed 6 months later. The 3cm rectal defect was repaired via a 3cm-long horizontal perineal incision. The 1.5cm urethral defect just below the prostate was not repaired. The patient underwent an optic internal urethrotomy 3Â months later for a 1.5cm-long urethral stricture. Several planned preventive urethral buginages were performed to avoid urethral stricture recurrence. At 12Â months postoperatively, there were no signs of a fistula and cancer recurrence. He now has a normal voiding and anal continence.
Severe rectal pain, bleeding, and local anterior necrotic proctitis are predictors of a rectourethral fistula. Urinary and fecal diversion is the first-step operation. Gracilis muscle interposition in conjunction with primary rectal repair but without urethral reconstruction is one of the reconstructive surgery options for moderate 2cm to 3cm rectourethral fistulas. Internal urethrotomy is a procedure for postoperative urethral strictures of 1.5cm in length.
Brachytherapy; Gracilis interposition; Prostate cancer; Radiotherapy; Rectal repair; Rectourethral fistula
Brachytherapy was developed to treat prostate cancer 50 years ago. Current advanced techniques using transrectal ultrasonography were established 25 years ago. Transrectal ultrasound (TRUS) has enabled the prostate to be viewed with improved resolution with the use of modern ultrasound machines. Moreover, the development of software that can provide images captured in real time has improved treatment outcomes. Other new radiologic imaging technologies or a combination of magnetic resonance and TRUS could be applied to brachytherapy in the future. The therapeutic value of brachytherapy for early-stage prostate cancer is comparable to that of radical prostatectomy in long-term follow-up. Nevertheless, widespread application of brachytherapy cannot be achieved for several reasons. The treatment outcome of brachytherapy varies according to the skill of the operator and differences in patient selection. Currently, only three radioactive isotopes are available for use in low dose rate prostate brachytherapy: I-125, Pd-103, and Cs-131; therefore, more isotopes should be developed. High dose rate brachytherapy using Ir-192 combined with external beam radiation, which is needed to verify the long-term effects, has been widely applied in high-risk patient groups. Recently, tumor-selective therapy or focal therapy using brachytherapy, which is not possible by surgical extraction, has been developed to maintain the quality of life in selected cases. However, this new application for prostate cancer treatment should be performed cautiously because we do not know the oncological outcome, and it would be an interim treatment method. This technique might evolve into a hybrid of whole-gland treatment and focal therapy.
Brachytherapy; Neoplasms; Prostate
C-arm X-ray fluoroscopy-based radioactive seed localization for intraoperative dosimetry of prostate brachytherapy is an active area of research. The fluoroscopy tracking (FTRAC) fiducial is an image-based tracking device composed of radio-opaque BBs, lines, and ellipses that provides an effective means for pose estimation so that three-dimensional reconstruction of the implanted seeds from multiple X-ray images can be related to the ultrasound-computed prostate volume. Both the FTRAC features and the brachytherapy seeds must be segmented quickly and accurately during the surgery, but current segmentation algorithms are inhibitory in the operating room (OR). The first reason is that current algorithms require operators to manually select a region of interest (ROI), preventing automatic pipelining from image acquisition to seed reconstruction. Secondly, these algorithms fail often, requiring operators to manually correct the errors. We propose a fast and effective ROI-free automatic FTRAC and seed segmentation algorithm to minimize such human intervention. The proposed algorithm exploits recent image processing tools to make seed reconstruction as easy and convenient as possible. Preliminary results on 162 patient images show this algorithm to be fast, effective, and accurate for all features to be segmented. With near perfect success rates and subpixel differences to manual segmentation, our automatic FTRAC and seed segmentation algorithm shows promising results to save crucial time in the OR while reducing errors.
segmentation; localization; C-arm; X-ray; fiducial; prostate brachytherapy
Periprostatic brachytherapy doses impact biochemical control. In this study, we evaluate extracapsular volumetric dosimetry following permanent prostate brachytherapy in patients entered in a multi-institutional community database.
Material and methods
In the database, 4547 patients underwent brachytherapy (3094 – 125I, 1437 – 103Pd and 16 – 131Cs). Using the originally determined prostate volume, a 5 mm, 3-dimensional peri-prostatic anulus was constructed around the prostate (except for a 2 mm posterior margin), and evaluated in its entirety and in 90° segments. Prostate dosimetric parameters consisted of a V100 and D90 while the annular dosimetry was reported as a V100.
The intraprostatic V100 and D90 for 103Pd, and 125I were statistically comparable when stratified by isotope and/or monotherapy vs. boost. The overall mean V100 for the periprostatic annulus was 62.8%. The mean V100 at the base (51.6%) was substantially less than the apex (73.5%) and midgland (65.9%). In addition, for all patients, the anterior V100 (45.7%) was less than the lateral (68.8%) and the posterior (75.0%). The geometric V100 annular differences were consistent when evaluated by isotope. Overall, the V100 was higher in the 125I cohort.
The optimal extracapsular brachytherapy dose and radial extent remains unknown, but will prove increasingly important with reductions and/or elimination of supplemental external beam radiation therapy. The large multi-institutional community database demonstrates periprostatic annular doses that are not as robust as those in selected high volume brachytherapy centers, and may be inadequate for optimal biochemical control following monotherapeutic brachytherapy, especially in higher risk patients.
brachytherapy; dosimetry; prostate cancer; treatment margins
The optimal protocol for 125I-transperineal prostatic brachytherapy (TPPB) in intermediate-risk prostate cancer (PCa) patients remains controversial. Data on the efficacy of combining androgen-deprivation therapy (ADT) with 125I-TPPB in this group remain limited and consequently the guidelines of the American Brachytherapy Society (ABS) provide no firm recommendations.
Seed and Hormone for Intermediate-risk Prostate Cancer (SHIP) 0804 is a phase III, multicenter, randomized, controlled study that will investigate the impact of adjuvant ADT following neoadjuvant ADT and 125I-TPPB. Prior to the end of March, 2011, a total of 420 patients with intermediate-risk, localized PCa will be enrolled and randomized to one of two treatment arms. These patients will be recruited from 20 institutions, all of which have broad experience of 125I-TPPB. Pathological slides will be centrally reviewed to confirm patient eligibility. The patients will initially undergo 3-month ADT prior to 125I-TPPB. Those randomly assigned to adjuvant therapy will subsequently undergo 9 months of adjuvant ADT. All participants will be assessed at baseline and at the following intervals: every 3 months for the first 24 months following 125I-TPPB, every 6 months during the 24- to 60-month post-125I-TPPB interval, annually between 60 and 84 months post-125I-TPPB, and on the 10th anniversary of treatment.
The primary endpoint is biochemical progression-free survival (BPFS). Secondary endpoints are overall survival (OS), clinical progression-free survival, disease-specific survival, salvage therapy non-adaptive interval, acceptability (assessed using the international prostate symptom score [IPSS]), quality of life (QOL) evaluation, and adverse events. In the correlative study (SHIP36B), we also evaluate biopsy results at 36 months following treatment to examine the relationship between the results and the eventual recurrence after completion of radiotherapy.
These two multicenter trials (SHIP0804 & SHIP36B) are expected to provide crucial data regarding the efficacy, acceptability and safety of adjuvant ADT. SHIP36B will also provide important information about the prognostic implications of PSA levels in intermediate-risk PCa patients treated with 125I-TPPB.
NCT00664456, NCT00898326, JUSMH-BRI-GU05-01, JUSMH-TRIGU0709
Permanent prostate brachytherapy (PPB) is a common treatment for early stage prostate cancer. While the modern approach using trans-rectal ultrasound guidance has demonstrated excellent outcome, the efficacy of PPB depends on achieving complete radiation dose coverage of the prostate by obtaining a proper radiation source (seed) distribution. Currently, brachytherapy seed placement is guided by trans-rectal ultrasound imaging and fluoroscopy. A significant percentage of seeds are not detected by trans-rectal ultrasound because certain seed orientations are invisible making accurate intra-operative feedback of radiation dosimetry very difficult, if not impossible. Therefore, intra-operative correction of suboptimal seed distributions cannot easily be done with current methods. Vibro-acoustography (VA) is an imaging modality that is capable of imaging solids at any orientation, and the resulting images are speckle free.
Objective and methods
The purpose of this study is to compare the capabilities of VA and pulse-echo ultrasound in imaging PPB seeds at various angles and show the sensitivity of detection to seed orientation. In the VA experiment, two intersecting ultrasound beams driven at f1 = 3.00 MHz and f2 = 3.020 MHz respectively were focused on the seeds attached to a latex membrane while the amplitude of the acoustic emission produced at the difference frequency 20 kHz was detected by a low frequency hydrophone.
Finite element simulations and results of experiments conducted under well-controlled conditions in a water tank on a series of seeds indicate that the seeds can be detected at any orientation with VA, whereas pulse-echo ultrasound is very sensitive to the seed orientation.
It is concluded that vibro-acoustography is superior to pulse-echo ultrasound for detection of PPB seeds.
Acoustic emission; Brachytherapy; Finite element; Pulse-echo; Ultrasound imaging; Vibro-acoustography
Prostate brachytherapy guided by transrectal ultrasound is a common treatment option for early stage prostate cancer. Prostate cancer accounts for 28% of cancer cases and 11% of cancer deaths in men with 217,730 estimated new cases and 32,050 estimated deaths in 2010 in the United States alone. The major current limitation is the inability to reliably localize implanted radiation seeds spatially in relation to the prostate. Multimodality approaches that incorporate X-ray for seed localization have been proposed, but they require both accurate tracking of the imaging device and segmentation of the seeds. Some use image-based radiographic fiducials to track the X-ray device, but manual intervention is needed to select proper regions of interest for segmenting both the tracking fiducial and the seeds, to evaluate the segmentation results, and to correct the segmentations in the case of segmentation failure, thus requiring a significant amount of extra time in the operating room. In this paper, we present an automatic segmentation algorithm that simultaneously segments the tracking fiducial and brachytherapy seeds, thereby minimizing the need for manual intervention. In addition, through the innovative use of image processing techniques such as mathematical morphology, Hough transforms, and RANSAC, our method can detect and separate overlapping seeds that are common in brachytherapy implant images. Our algorithm was validated on 55 phantom and 206 patient images, successfully segmenting both the fiducial and seeds with a mean seed segmentation rate of 96% and sub-millimeter accuracy.
prostate brachytherapy; seed localization; X-ray; non-isocentric C-arm; fiducial; segmentation; overlapping seeds
Prostatic calculi are common and are associated with inflammation of the prostate. Recently, it has been suggested that this inflammation may be associated with prostate carcinogenesis. The aim of this study was to investigate the relationship between prostatic calculi and prostate cancer (PCa) in prostate biopsy specimens. We retrospectively analyzed 417 consecutive patients who underwent transrectal ultrasonography (TRUS) and prostate biopsies between January 2005 and January 2008. Based on the biopsy findings, patients were divided into benign prostatic hyperplasia and PCa groups. TRUS was used to detect prostatic calculi and to measure prostate volume. The correlations between PCa risk and age, serum total PSA levels, prostate volume, and prostatic calculi were analyzed. Patient age and PSA, as well as the frequency of prostatic calculi in the biopsy specimens, differed significantly between both the groups (P < 0.05). In the PCa group, the Gleason scores (GSs) were higher in patients with prostatic calculi than in patients without prostatic calculi (P = 0.023). Using multivariate logistic regression analysis, we found that patient age, serum total PSA and prostate volume were risk factors for PCa (P = 0.001), but that the presence of prostatic calculi was not associated with an increased risk of PCa (P = 0.13). In conclusion, although the presence of prostatic calculi was not shown to be a risk factor for PCa, prostatic calculi were more common in patients with PCa and were associated with a higher GS among these men.
calculi; prostate; prostatic neoplasms; risk factors
To analyze the correlations among comorbidity and overall survival (OS), biochemical progression-free survival (b-PFS) and toxicity in elderly patients with localized prostate cancer treated with 125I brachytherapy.
Elderly men, aged ≥65 years, with low-intermediate risk prostate cancer, were treated with permanent 125I brachytherapy as monotherapy. Comorbidity data were obtained from medical reports using age-adjusted Charlson comorbidity index (a-CCI). The patients were categorized into two age groups (<75 and ≥75 years old), and two comorbidity score groups (a-CCI ≤3 and >3). Toxicity was scored with Radiation Therapy Oncology Group (RTOG) scale.
From June 2003 to October 2009, a total of 92 elderly patients underwent prostate brachytherapy, including 57 men (62%) with low-risk prostate cancer, and 35 men (38%) with intermediate-risk prostate cancer. The median age of patients was 75 years (range, 65-87 years). Forty-seven patients (51%) had a-CCI ≤3 and 45 patients (49%) a-CCI >3. With a median follow-up period of 56 months (range, 24-103 months), the 5-year actuarial OS and b-PFS were 91.3% and 92.4% respectively, without statistical significance between two Charlson score groups. Toxicity was mild. None of the patients experienced gastrointestinal (GI) toxicity, and only 4 patiens (4%) experienced late genitourinary (GU) grade-3 (G3) toxicity. No correlation between acute GU and GI toxicity and comorbidity was showed (P=0.50 and P=0.70, respectively).
Our data suggest that elderly men with low-intermediate risk prostate cancer and comorbidity can be considered for a radical treatment as 125I low-dose rate brachytherapy.
Prostate cancer; brachytherapy; elderly; comorbidity; toxicity; overall survival; biochemical control
In a community-based study, the relationship between age and human prostate size was investigated in a population of men between the ages of 40 and 70 years to determine the normal prostate increase curve equation. One thousand male volunteers were randomly recruited from the Shanghai community, and the length, width, height, volume of the transition zone (TZ) and the whole prostates were measured by transrectal ultrasound (TRUS). Each volunteer was evaluated by the International Prostate Symptom Score (IPSS). Among those who completed the examination, the mean prostate parameters were all positively associated with increased age. There were statistically significant differences between each age group (P<0.05). The mean transition zone volume (TZV) had a higher increase rate with age than the mean total prostate volume (TPV), indicating that the enlargement of the TZ contributed the most to the increase in TPV. While all prostate parameters were positively correlated with the IPSS, the strongest correlation was associated with the TZ length (TZL) and TZV. The growth curve equations for prostate width, height and length were also positively associated with increasing age.
benign prostate hyperplasia (BPH); growth equation; International Prostate Symptom Score (IPSS); prostate; transrectal ultrasound (TRUS)