Cold spot mapping inferred from MRI at time of failure predicts biopsy-proven local failure after permanent seed brachytherapy in prostate cancer patients: implications for focal salvage brachytherapy.

Background And Purpose: (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf.

Material And Methods: Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI.

Feasibility of MR imaging/MR spectroscopy-planned focal partial salvage permanent prostate implant (PPI) for localized recurrence after initial PPI for prostate cancer.

Purpose: To assess the feasibility of magnetic resonance imaging (MRI)-planned partial salvage permanent prostate implant (psPPI) among patients with biopsy-proven local recurrence after initial PPI without evidence of distant disease.

Methods And Materials: From 2003-2009, 15 patients underwent MRI/magnetic resonance spectroscopy (MRS) planning for salvage brachytherapy (psPPI, I-125 [n=14; 144 Gy]; Pd-103 [n=1; 125 Gy]) without hormone therapy. Full dose was prescribed to areas of recurrence and underdosage, without entire prostate implantation.

Inverse planning optimization for hybrid prostate permanent-seed implant brachytherapy plans using two source strengths.

The purpose is to demonstrate the ability to generate clinically acceptable prostate permanent seed implant plans using two seed types which are identical except for their activity. The IPSA inverse planning algorithms were modified to include multiple dose matrices for the calculation of dose from different sources, and a selection algorithm was implemented to allow for the swapping of source type at any given source position. Five previously treated patients with a range of prostate volumes from 20-48 cm3 were re-optimized under two hybrid scenarios: (1) using 0.

Equivalent biochemical control and improved prostate-specific antigen nadir after permanent prostate seed implant brachytherapy versus high-dose three-dimensional conformal radiotherapy and high-dose conformal proton beam radiotherapy boost.

Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT.

Patients And Methods: A total of 249 patients were treated with PPI at the University of California, San Francisco, and the outcomes were compared with those from a 3D-CRT cohort and the published results of a high-dose CPBRT boost (CPBRTB) trial.

Salvage permanent perineal radioactive-seed implantation for treating recurrence of localized prostate adenocarcinoma after external beam radiotherapy.

Objective: To assess our experience with salvage permanent perineal radioactive-seed implantation (SPPI) as a possible therapeutic option for recurrent prostate adenocarcinoma, as salvage therapies for recurrences after definitive external beam radiotherapy (EBRT) for localized adenocarcinoma of the prostate are associated with significant morbidity and biochemical failure.

Patients And Methods: We retrospectively analysed on patients who had SPPI for localized recurrent prostate adenocarcinoma from 1996 to 2007 after primary treatment with EBRT. Excluded were patients who had other primary treatment or had no follow-up.

Proposed rectal dose constraints for patients undergoing definitive whole pelvic radiotherapy for clinically localized prostate cancer.

Purpose: Although several institutions have reported rectal dose constraints according to threshold toxicity, the plethora of trials has resulted in multiple, confusing dose-volume histogram recommendations. A set of standardized, literature-based constraints for patients undergoing whole pelvic radiotherapy (RT) for prostate cancer would help guide the practice of prostate RT. The purpose of this study was to develop these constraints, demonstrate that they are achievable, and assess the corresponding rectal toxicity.

Prostate cancer: role of pretreatment MR in predicting outcome after external-beam radiation therapy--initial experience.

Purpose: To retrospectively determine if pretreatment endorectal magnetic resonance (MR) imaging findings are predictive of outcome in patients who undergo external-beam radiation therapy for prostate cancer.

Materials And Methods: Committee on Human Research approval, with waiver of the requirement for informed consent, was obtained for this HIPAA-compliant study. Eighty men with biopsy-proved prostate cancer (mean age, 59 years; range, 47-75 years) who underwent endorectal MR imaging of the prostate prior to external-beam radiation therapy were retrospectively identified; details of baseline tumor characteristics, treatment, and outcome were recorded.

Class solution for inversely planned permanent prostate implants to mimic an experienced dosimetrist.

The purpose of this paper is to present a method for the selection of inverse planning parameters and to establish a set of inverse planning parameters (class solution) for the inverse planning included in a commercial permanent prostate implant treatment planning system. The manual planning of more than 750 patients since 1996 led to the establishment of general treatment planning rules. A class solution is tuned to fulfill the treatment planning rules and generate equivalent implants.

Three-dimensional conformal external beam radiotherapy compared with permanent prostate implantation in low-risk prostate cancer based on endorectal magnetic resonance spectroscopy imaging and prostate-specific antigen level.

Purpose: To evaluate the metabolic response by comparing the time to resolution of spectroscopic abnormalities (TRSA) and the time to prostate-specific antigen level in low-risk prostate cancer patients after treatment with three-dimensional conformal external beam radiotherapy (3D-CRT) compared with permanent prostate implantation (PPI). Recent studies have suggested that the treatment of low-risk prostate cancer yields similar results for patients treated with 3D-CRT or PPI.

Methods And Materials: A total of 50 patients, 25 in each group, who had been treated with 3D-CRT or PPI, had undergone endorectal magnetic resonance spectroscopy imaging before and/or at varying times after therapy.

Use of MRI and spectroscopy in evaluation of external beam radiotherapy for prostate cancer.

Purpose: To characterize the metabolic response in the prostate, the time to resolution of disease, and the correlation between magnetic resonance imaging (MRI) with spectroscopy (MRSI) results, biopsy findings, and serum prostate-specific antigen (PSA) level after external beam radiotherapy.

Methods And Materials: A total of 55 patients underwent MRSI before and/or at varying times after external beam radiotherapy. The percentage of the cancerous, healthy, and atrophic voxels was calculated, and the time to resolution of disease was determined and compared with the PSA nadir.

Endorectal MR imaging and MR spectroscopic imaging for locally recurrent prostate cancer after external beam radiation therapy: preliminary experience.

Purpose: To evaluate endorectal magnetic resonance (MR) imaging and MR spectroscopic imaging for the depiction of locally recurrent prostate cancer after external beam radiation therapy.

Materials And Methods: Endorectal MR imaging and MR spectroscopic imaging were performed in 21 patients with biochemical failure after external beam radiation therapy for prostate cancer. Two readers independently and retrospectively reviewed MR images and rated the likelihood of recurrent tumor on a five-point scale.

The effect of the radial function on I-125 seeds used for permanent prostate implantation.

The purpose of this study was to evaluate the integrity of eight commercially-available low-activity Iodine-125 (125I) seeds for their radial function g(r) and its effect on the dose delivered to the adjacent critical structures when used in permanent prostate implants (PPI). Ten previously treated patients were retrospectively used in this comparison. The Amersham Health Oncura seed was used to peripherally design an isodose distribution with urethral and anterior rectal wall sparing.

Time to metabolic atrophy after permanent prostate seed implantation based on magnetic resonance spectroscopic imaging.

Purpose: To characterize the time to metabolic atrophy (TMA) after permanent prostate implantation (PPI) using combined MRI and magnetic resonance spectroscopic imaging (MRSI) compared with the time to prostate-specific antigen (PSA) nadir.

Methods And Materials: This study was based on a posttreatment analysis comparing the MRI/MRSI findings with the PSA levels of 65 patients treated with PPI alone or combined with external beam radiotherapy and/or HT. The fraction of interpretable voxels demonstrating metabolic atrophy was used to compare the TMA with the time to PSA nadir.

(Non)-migration of radiopaque markers used for on-line localization of the prostate with an electronic portal imaging device.

Purpose: Radiopaque gold markers can be implanted in the prostate to visualize its position on portal images during radiation therapy. This procedure assumes that the markers do not move within the prostate. In this work we test this assumptiom.

The effect of beam energy and number of fields on photon-based IMRT for deep-seated targets.

Purpose: To examine the influence of energy and number of beams on nontarget dose when using intensity-modulated radiation therapy (IMRT) to treat deep-seated targets.

Methods And Materials: Ten patients with prostate cancer (36-226 cc) treated locally to 75.6 Gy were studied.