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Intensity Modulated Proton Therapy as a Boost Treatment after Prostate Seed Implant: A Treatment Planning Study  [PDF]
Junqing Wu, Huanmei Wu, Chee-Wai Cheng
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2015, DOI: 10.4236/ijmpcero.2015.41011
Abstract:
Purpose: Combination of Prostate Seed Implant (PSI) with External Beam Radiation Therapy (EBRT) remains as an attractive option for patients with intermediate or high-risk prostate cancer. One of the most widely used approaches is to use external beam radiation therapy (EBRT) to deliver boost doses after permanent prostate seed implant (PSI). In this study, the feasibility of using Intensity Modulated Proton Therapy (IMPT) as an alternative EBRT boost treatment for PSI patients was investigated in the presence of a large number of high Z metallic seeds. The dosimetry of IMPT boost plans was compared with that of conventional Intensity Modulated Radiation Therapy (IMRT) boost plans. Methods: Ten post prostate seed implants with seeds of I-125 were randomly selected for this study. Proton treatment plans were created with two lateral opposed proton beams in Eclipse treatment planning system. IMRT boost plans were generated with seven co-planner beams for comparison. Several plan evaluation parameters such as the planning target volume (PTV) dose homogeneity, dose conformity and dose to surrounding normal tissues were evaluated. Results: Compared to conventional IMRT boost plans, IMPT demonstrated better sparing of normal tissues while providing similar satisfactory PTV coverage. The high Z implanted seeds is not a problem for IMPT as boost treatment. Conclusions: PSI with an IMPT boost can be a valuable option for prostate cancer patient treatment. It delivers comparable or better radiation dose distribution in terms of normal tissue sparing compared to IMRT boost plan.
Prophylactic urethral stenting with Memokath 028SW in prostate cancer patients undergoing prostate 125I seed implants: phase I/II study
Samuel T. Chao,Kenneth Angermeier,Eric A. Klein,Chandana A. Reddy
Journal of Contemporary Brachytherapy , 2011,
Abstract: Purpose: To study the feasibility/toxicity of urethral stenting with the Memokath 028SW stent in patients undergoing prostate implant (PI) for prostate adenocarcinoma. Material and methods: An Investigational Device Exemption from the Food and Drug Administration (FDA) and institutional review board (IRB) approval were obtained. Twenty patients enrolled. Baseline American Urological Association (AUA) score was obtained prior to PI. Follow-up information was obtained with weekly phone calls for the first 12 weeks and biweekly calls for the next 12 weeks to assess toxicity and AUA score. Removal of the stent was planned at six months after PI, or earlier due to excessive toxicity/patient request. Results: Median age was 66.5 years. The median prostate volume was 39 cc (range: 10-90). The median baseline AUA score was 7.5 (range: 1-21). Three patients required intermittent self-catheterization (ISC) within 3 days after PI. No patients required ISC beyond day 3 after PI. The median duration of ISC was 1 day (range: 1-2). AUA scores returned to baseline values 6 weeks after PI. The week 6 AUA score was 10 (range: 4-16). Seven patients (35%) underwent early removal because of patient preference. The reasons were: incontinence (n = 3), discomfort (n = 2), hematuria (n = 1), and obstructive symptoms (n = 1). The median time of stent removal in these patients was 13.9 weeks (range: 0.9-21.4). Thirteen patients (65%) had ISC and/or urinary catheterization post stent removal. Median time for ISC use was 10 days (range: 1-90). Conclusions: Urethral stenting with Memokath in patients undergoing PI was feasible, but resulted in relatively high rate of urinary incontinence and discomfort. Given the adverse effects experienced by patients of this study, further studies should focus only on patients with highest risk of urinary obstruction from PI or those with obstruction needing ISC.
Radiobiological evaluation of the influence of dwell time modulation restriction in HIPO optimized HDR prostate brachytherapy implants  [cached]
Panayiotis Mavroidis,Zaira Katsilieri,Vasiliki Kefala,Natasa Milickovic
Journal of Contemporary Brachytherapy , 2010,
Abstract: Purpose: One of the issues that a planner is often facing in HDR brachytherapy is the selective existence of high dose volumes around some few dominating dwell positions. If there is no information available about its necessity (e.g. location of a GTV), then it is reasonable to investigate whether this can be avoided. This effect can be eliminated by limiting the free modulation of the dwell times. HIPO, an inverse treatment plan optimization algorithm, offers this option.In treatment plan optimization there are various methods that try to regularize the variation of dose non-uniformity using purely dosimetric measures. However, although these methods can help in finding a good dose distribution they do not provide any information regarding the expected treatment outcome as described by radiobiology based indices.Material and methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO and modulation restriction (MR) has been compared to alternative plans with HIPO and free modulation (without MR).All common dose-volume indices for the prostate and the organs at risk have been considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by calculating the response probabilities of the tumors and organs-at-risk (OARs) involved in these prostate cancer cases. The radiobiological models used are the Poisson and the relative seriality models. Furthermore, the complication-free tumor control probability, P+ and the biologically effective uniform dose (D = ) were used for treatment plan evaluation and comparison.Results: Our results demonstrate that HIPO with a modulation restriction value of 0.1-0.2 delivers high quality plans which are practically equivalent to those achieved with free modulation regarding the clinically used dosimetric indices.In the comparison, many of the dosimetric and radiobiological indices showed significantly different results. The modulation restricted clinical plans demonstrated a lower total dwell time by a mean of 1.4% that was proved to be statistically significant (p = 0.002). The HIPO with MR treatment plans produced a higher P+ by 0.5%, which stemmed from a better sparing of the OARs by 1.0%.Conclusions: Both the dosimetric and radiobiological comparison shows that the modulation restricted optimization gives on average similar results with the optimization without modulation restriction in the examined clinical cases. Concluding, based on our results, it appears that the applied dwell time regularization technique is expected
Assessment of I-125 seed implant accuracy when using the live-planning technique for low dose rate prostate brachytherapy  [cached]
Moorrees Joshua,Lawson John M,Marcu Loredana G
Radiation Oncology , 2012, DOI: 10.1186/1748-717x-7-196
Abstract: Background Low risk prostate cancers are commonly treated with low dose rate (LDR) brachytherapy involving I-125 seeds. The implementation of a ‘live-planning’ technique at the Royal Adelaide Hospital (RAH) in 2007 enabled the completion of the whole procedure (i.e. scanning, planning and implant) in one sitting. ‘Live-planning’ has the advantage of a more reliable delivery of the planned treatment compared to the ‘traditional pre-plan’ technique (where patient is scanned and planned in the weeks prior to implant). During live planning, the actual implanted needle positions are updated real-time on the treatment planning system and the dosimetry is automatically recalculated. The aim of this investigation was to assess the differences and clinical relevance between the planned dosimetry and the updated real-time implant dosimetry. Methods A number of 162 patients were included in this dosimetric study. A paired t-test was performed on the D90, V100, V150 and V200 target parameters and the differences between the planned and implanted dose distributions were analysed. Similarly, dosimetric differences for the organs at risk (OAR) were also evaluated. Results Small differences between the primary dosimetric parameters for the target were found. Still, the incidence of hotspots was increased with approximately 20% for V200. Statistically significant increases were observed in the doses delivered to the OAR between the planned and implanted data; however, these increases were consistently below 3% thus probably without clinical consequences. Conclusions The current study assessed the accuracy of prostate implants with I-125 seeds when compared to initial plans. The results confirmed the precision of the implant technique which RAH has in place. Nevertheless, geographical misses, anatomical restrictions and needle displacements during implant can have repercussions for centres without live-planning option if dosimetric changes are not taken into consideration.
Brachytherapy for Prostate Cancer: A Systematic Review  [PDF]
Georgios Koukourakis,Nikolaos Kelekis,Vassilios Armonis,Vassilios Kouloulias
Advances in Urology , 2009, DOI: 10.1155/2009/327945
Abstract: Low-dose rate brachytherapy has become a mainstream treatment option for men diagnosed with prostate cancer because of excellent long-term treatment outcomes in low-, intermediate-, and high-risk patients. To a great extend due to patient lead advocacy for minimally invasive treatment options, high-quality prostate implants have become widely available in the US, Europe, and Japan. High-dose-rate (HDR) afterloading brachytherapy in the management of localised prostate cancer has practical, physical, and biological advantages over low-dose-rate seed brachytherapy. There are no free live sources used, no risk of source loss, and since the implant is a temporary procedure following discharge no issues with regard to radioprotection use of existing facilities exist. Patients with localized prostate cancer may benefit from high-dose-rate brachytherapy, which may be used alone in certain circumstances or in combination with external-beam radiotherapy in other settings. The purpose of this paper is to present the essentials of brachytherapies techniques along with the most important studies that support their effectiveness in the treatment of prostate cancer.
Conformal prostate brachytherapy guided by realtime dynamic dose calculations using permanent 125iodine implants: technical description and preliminary experience
Prada,Pedro J.; Juan,German; Fernández,José; H,González-Suárez; Martínez,álvaro; González,José; Alonso,Ana;
Archivos Espa?oles de Urología (Ed. impresa) , 2006, DOI: 10.4321/S0004-06142006000900021
Abstract: objetive: low dose rate (ldr) prostate brachytherapy (permanent 125i or 103pd seeds) is an accepted treatment option for low risk prostate cancer patients. however, differences in prostate spatial location, volume and gland deformation between the images obtained during pre-planning and later on during the implant procedure prevent the pre-planned intended dose to be accurately delivered. we are reporting on a new technique based on interactive real-time dynamic intra-operative dose calculation with avoidance of post-implant ct for final dosimetry. the reasons leading us to implementing this new technique are discussed and preliminary results reported. methods: a pre-planning trus for volumetric analysis is performed in all our patients prior to implantation. this trus accomplishes two objectives: 1) assessment of implantability of the gland, of organs at risk and anatomical considerations and 2) determination of seed activity and total number of seeds. on the day of the implant, new trus images from base to apex are obtained using a motorized stepper connected to the ultrasound and planning system. each real time needle position placed on the target is identified and capture by the planning system in the true position. once all real needle positions have been captured, dosimetry is performed intra-operatively and the physician approves the corresponding isodoses on real time. flexible cystoscopy is then performed followed by seed placement. each seed implanted is then identified upon withdrawing the needle using trus guidance. this allows real-time intra-operative dosimetric analysis, allowing for correction of under-dosed zones during implantation in an interactive dynamic manner. peripheral loading is used. results: we began our ldr prostate brachytherapy program on 1999. while we have treated 700 patients with ldr, the last 63 patients were treated with our real time dynamic intra-operative planning system. the median time duration for the procedure was 90 minut
Incidence of seed migration to the chest, abdomen, and pelvis after transperineal interstitial prostate brachytherapy with loose 125I seeds
Akitomo Sugawara, Jun Nakashima, Etsuo Kunieda, Hirohiko Nagata, Ryuichi Mizuno, Satoshi Seki, Yutaka Shiraishi, Ryuichi Kouta, Mototsugu Oya, Naoyuki Shigematsu
Radiation Oncology , 2011, DOI: 10.1186/1748-717x-6-130
Abstract: We reviewed the records of 267 patients who underwent prostate brachytherapy with loose 125I seeds. After seed implantation, orthogonal chest radiographs, an abdominal radiograph, and a pelvic radiograph were undertaken routinely to document the occurrence and sites of seed migration. The incidence of seed migration to the chest, abdomen, and pelvis was calculated. All patients who had seed migration to the abdomen and pelvis subsequently underwent a computed tomography scan to identify the exact location of the migrated seeds. Postimplant dosimetric analysis was undertaken, and dosimetric results were compared between patients with and without seed migration.A total of 19,236 seeds were implanted in 267 patients. Overall, 91 of 19,236 (0.47%) seeds migrated in 66 of 267 (24.7%) patients. Sixty-nine (0.36%) seeds migrated to the chest in 54 (20.2%) patients. Seven (0.036%) seeds migrated to the abdomen in six (2.2%) patients. Fifteen (0.078%) seeds migrated to the pelvis in 15 (5.6%) patients. Seed migration occurred predominantly within two weeks after seed implantation. None of the 66 patients had symptoms related to the migrated seeds. Postimplant prostate D90 was not significantly different between patients with and without seed migration.We showed the incidence of seed migration to the chest, abdomen and pelvis. Seed migration did not have a significant effect on postimplant prostate D90.Seed migration is a well-recognized event that occurs after transperineal interstitial prostate brachytherapy, and it is observed more often with loose seeds than with linked seeds [1-5].It is well known that the most frequent site of seed migration is the chest. The American Brachytherapy Society has advised that a chest radiograph should be undertaken at the first follow-up visit to scan the lungs for embolized seeds [6]. Consequently, the incidence of seed migration to the chest has been well reported [1,2,4,5,7-19]. However, documentation of the incidence of seed migration
Mixed integer programming improves comprehensibility and plan quality in inverse optimization of prostate HDR-brachytherapy  [PDF]
Bram L. Gorissen,Dick den Hertog,Aswin L. Hoffmann
Physics , 2014, DOI: 10.1088/0031-9155/58/4/1041
Abstract: Current inverse treatment planning methods that optimize both catheter positions and dwell times in prostate HDR brachytherapy use surrogate linear or quadratic objective functions that have no direct interpretation in terms of dose-volume histogram (DVH) criteria, do not result in an optimum or have long solution times. We decrease the solution time of existing linear and quadratic dose-based programming models (LP and QP, respectively) to allow optimizing over potential catheter positions using mixed integer programming. An additional average speed-up of 75% can be obtained by stopping the solver at an early stage, without deterioration of the plan quality. For a fixed catheter configuration, the dwell time optimization model LP solves to optimality in less than 15 seconds, which confirms earlier results. We propose an iterative procedure for QP that allows to prescribe the target dose as an interval, while retaining independence between the solution time and the number of dose calculation points. This iterative procedure is comparable in speed to the LP model, and produces better plans than the non-iterative QP. We formulate a new dose-volume based model that maximizes $V_{100\%}$ while satisfying pre-set DVH-criteria. This model optimizes both catheter positions and dwell times within a few minutes depending on prostate volume and number of catheters, optimizes dwell times within 35 seconds, and gives better DVH statistics than dose-based models. The solutions suggest that the correlation between objective value and clinical plan quality is weak in existing dose-based models.
Treatment plan comparison of Linac step and shoot,Tomotherapy, RapidArc, and Proton therapy for prostate cancer using dosimetrical and biological index  [PDF]
Suk Lee,Yuan Jie Cao,Kyung Hwan Chang,Jang Bo Shim,Kwang Hyeon Kim,Nam Kwon Lee,Young Je Park,Chul Yong Kim,Sam Ju Cho,Sang Hoon Lee,Chul Kee Min,Woo Chul Kim,Kwang Hwan Cho,Hyun Do Huh,Sangwook Lim,Dongho Shin
Physics , 2015,
Abstract: The purpose of this study was to use various dosimetrical indices to determine the best IMRT modality technique for treating patients with prostate cancer. Ten patients with prostate cancer were included in this study. Intensity modulated radiation therapy plans were designed to include different modalities, including the linac step and shoot, Tomotherapy, RapidArc, and Proton systems. Various dosimetrical indices, like the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Biological indices such as the generalized equivalent uniform dose (gEUD), based tumor control probability (TCP), and normal tissue complication probability (NTCP) were also calculated and used to compare the treatment plans. The RapidArc plan attained better PTV coverage, as evidenced by its superior PITV, CI, TCI, MHI, and CN values. Regarding OARs, proton therapy exhibited superior dose sparing for the rectum and bowel in low dose volumes, whereas the Tomotherapy and RapidArc plans achieved better dose sparing in high dose volumes. The QF scores showed no significant difference among these plans (p=0.701). The average TCPs for prostate tumors in the RapidArc, Linac, and Proton plans were higher than the average TCP for Tomotherapy (98.79%, 98.76%, and 98.75% vs. 98.70%, respectively). Regarding the rectum NTCP, RapidArc showed the most favorable result (0.09%), whereas Linac resulted in the best bladder NTCP (0.08%).
Iodine-125 Seed Implantation (Permanent Brachytherapy) for Clinically Localized Prostate Cancer  [PDF]
Ebara,Shin,Katayama,Yoshihisa,Tanimoto,Ryuta,Edamura,Kohei
Acta Medica Okayama , 2008,
Abstract: From January 2004 to March 2007, 308 patients with clinically localized prostate cancer were treated using iodine-125 (125I) seed implantation (permanent brachytherapy) at Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences. We evaluated the treatment’s effi cacy and morbidity in 300 prostate cancer patients who were followed up for more than 1 month after brachytherapy. Based on the National Comprehensive Cancer Network (NCCN) guidelines, patients with a prostate volume of less than 40 ml in transrectal ultrasound imaging were classifi ed as low or intermediate risk. The median patient age was 67 years (range 50 to 79 years), the median prostate-specific antigen (PSA) value before biopsy was 6.95 ng/ml (range 1.13 to 24.7 ng/ml), and the median prostate volume was 24.33 ml (range 9.3 to 41.76 ml). The median follow-up was 18 months (range 1 to 36 months) and the PSA levels decreased in almost all patients after brachytherapy. Although 194 of 300 patients (64.7%) complained of diffi culty in urination, pollakisuria/urgency, miction pain, and/or urinary incontinence, all of which might be associated with radiation prostatitis during the fi rst month after brachytherapy, these symptoms gradually improved. 125I seed implantation brachytherapy is safe and eff ective for localized prostate cancer within short-term follow up.
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