Analysis of prostate bed motion using daily cone-beam computed tomography during postprostatectomy radiotherapy.

PURPOSE: To report on the interfraction total positioning error of the postoperative prostate bed and to quantify its components (bony misalignment [BM] and prostate bed motion [PBM]) using daily kilovoltage cone-beam computed tomography (CBCT). The role of an adaptive radiotherapy schedule (ART) was investigated. METHODS AND MATERIALS: A total of 547 daily CBCT images from 15 consecutive patients who had been treated with prostate bed radiotherapy were retrospectively analyzed. The positioning error was measured by rigid co-registration of the daily CBCT with pretreatment CT planning scan. The total positioning error was quantified by co-registration of the CBCT with the CT planning scan to match the anterior rectal wall. Automatic bony pelvis co-registration was performed to separate BM and PBM. The ART was determined by the average total positioning error from the first 5 CBCT images. RESULTS: The systematic error for the total positioning error in the left-right, superoinferior, and anteroposterior direction was 2.69, 2.00, and 2.65 mm with a random error of 1.99, 1.49, and 2.25 mm, resulting in a planning target volume margin of 8, 6, and 8 mm, respectively. ART reduced the margin by 54%, 44%, and 40%, respectively. Systematic errors in the left-right, superoinferior, and anteroposterior direction for BM was 2.66, 1.83, and 2.60 mm and for PBM was 0.44, 0.92, and 2.50 mm with a random error of 1.88, 1.24, and 1.77 mm for BM and 0.99, 1.38, and 2.32 mm for PBM, respectively. CONCLUSION: Without treatment verifications, 6-8-mm planning target volume margins are required because of PBM and BM. The anteroposterior PBM was significant. An ART protocol can reduce these planning target volume margins.

Vaporización fotoselectiva de la prostata (VFP) vs enucleación de la próstata con láser Holmio (HOLEP): resultados actuales y estrategias / PVP vs HOLEP current outcomes and future strategies

La vaporización foto selectiva de la próstata (VFP), con un láser de fosfato de titanio y potasio (KTP) y la enucleación de la próstata con láser Holmio (HoLEP) representan en la actualidad las técnicas más prometedoras en el tratamiento de la hiperplasia benigna de próstata (HBP) asociada con obstrucción benigna de próstata (OBP). Las características específicas del láser y las interacciones óptimas entre el láser y el tejido prostático resultan en una uniforme y eficiente ablación de la próstata con la consiguiente formación de una celda prostática claramente desobstruida. El KTP y el HoLEP pueden ser considerados procedimientos ambulatorios, ya que solo requieren unas pocas horas de cateterización y están asociados con mínimo discomfort postoperatorio, mientras que al mismo tiempo ofrecen resultados al menos equivalentes a los estándares de referencia de la resección transuretral de próstata y la prostatectomía abierta. No hay duda de que se necesitan grandes estudios con seguimiento más largo para definir con mayor precisión la duración de los resultados del KTP y el HoLEP en el manejo de la HBP. Esta revisión abordará cuestiones de actualidad acerca de cómo se llevan a cabo ambas técnicas, sus resultados y limitaciones, así como su papel en el manejo futuro de la HBP(AU)

Photoselective vaporization of the prostate (PVP) with a potassium titanyl phosphate (KTP) láser and Holmium láser enucleation of the prostate (HoLEP) currently represent the most promising new technologies applied to the treatment of benign prostatic hyperplasia (BPH) associated with benign prostatic obstruction (BPO). The specific láser-light characteristics and the optimal interactions between lásers and prostatic tissue result in an even and efficient ablation of the prostate resulting in the formation of a clearly de-obstructed prostate cavity. PVP and HoLEP can be considered day-case procedures, as they require only a few hours of catheterization and are associated with minimal postoperative discomfort, while at the same time they offer results at least equivalent to the reference standards transurethral resection of the prostate and open prostatectomy. There is no doubt that larger studies with longer follow-up are necessary to further define the durability of results of PVP and HoLEP in the management of BPH, this review will address current issues regarding how both techniques are performed, their results and limitations as well as their role in the future management of BPH(AU)

Does a history of previous surgery or radiation to the prostate affect outcomes of robot-assisted radical prostatectomy?

OBJECTIVE: To evaluate retrospectively whether or not previous treatment to the prostate alters the perioperative outcomes from robot-assisted radical prostatectomy (RARP) after the initial 'learning curve', as there are conflicting data on outcomes of RP in patients with previous treatment to the prostate. PATIENTS AND METHODS: We retrospectively reviewed the charts of patients who had RARP between March 2005 and August 2007, and analysed demographic, perioperative variables and pathological data. In all, 510 patient charts were reviewed, identifying 24 patients with a history of previous treatment to the prostate including transurethral resection or incision of the prostate, transurethral microwave therapy, transurethral needle ablation, photoselective vaporization, simple prostatectomy, external beam radiotherapy, brachytherapy, and open bladder neck reconstruction (group 1) and 486 with no previous treatment (group 2). RESULTS: There was no significant difference between the groups in body mass index, clinical stage, grade or prostate volume, but the patients in group 1 were older (70 vs 65 years, P = 0.001). Outcome analysis comparing groups 1 and 2 showed an estimated blood loss of 155 vs 137 mL, length of hospital stay of 2.2 vs 1.5 days, operative duration of 200 vs 186 min and catheter time of 12 vs 8 days, respectively; only the last was statistically significant (P = 0.03). There was an 8.3% and 6.8% complication rate in groups 1 and 2, respectively, and the respective overall positive margin rate was 20.8% and 22.6%. CONCLUSIONS: A history of previous treatment of the prostate does not appear to compromise the perioperative outcomes of RARP.

[Laser therapy in the complex treatment of prostatic tuberculosis at the sanatorium stage of rehabilitation].

Seventy nine patients with prostatic tuberculosis were examined and treated at the specialized "Glukhovskaya" sanatorium. All the patients were divided into 2 groups: a study group and a control one. In the study group patients, low-intensity laser radiotherapy was additionally performed in combination with etiological and pathogenetical treatments. The performed studies demonstrated that in the patients exposed to low-intensity laser radiation, there was a rapid relief of dysuric symptoms, cessation or diminishment of the signs of copulative dysfunction; positive changes in life quality indices and laboratory parameters were statistically significantly more frequently and more rapidly recorded. Laser therapy simultaneously was found to affect a few links of the pathogenesis of genitourinary tuberculosis, to have limited number of contraindications, to be well tolerated, and to be an effective method of the complex treatment of patients with prostatic tuberculosis during sanatorium rehabilitation.

Prostatic edema in 125I permanent prostate implants: dynamical dosimetry taking volume changes into account.

The purpose of this study is to determine the impact of edema on the dose delivered to the target volume. An evaluation of the edema characteristics was first made, and then a dynamical dosimetry algorithm was developed and used to compare its results to a standard clinical (static) dosimetry. Source positions and prostate contours extracted from 66 clinical cases on images taken at different points in time (planning, implant day, post-implant evaluation) were used, via the mean interseed distance, to characterize edema [initial increase (deltar0), half-life (tau)]. An algorithm was developed to take into account the edema by summing a time series of dose-volume histograms (DVHs) with a weight based on the fraction of the dose delivered during the time interval considered. The algorithm was then used to evaluate the impact of edema on the dosimetry of permanent implants by comparing its results to those of a standard clinical dosimetry. The volumetric study yielded results as follows: the initial prostate volume increase was found to be 1.58 (ranging from 1.15 to 2.48) and the edema half-life, approximately 30 days (range: 3 to 170 days). The dosimetric differences in D90 observed between the dynamic dosimetry and the clinical one for a single case were up to 15 Gy and depended on the edema half-life and the initial volume increase. The average edema half-life, 30 days, is about 3 times longer than the previously reported 9 days. Dosimetric differences up to 10% of the prescription dose are observed, which can lead to differences in the quality assertion of an implant. The study of individual patient edema resorption with time might be necessary to extract meaningful clinical correlation or biological parameters in permanent implants.

Post-implant computed tomography-magnetic resonance prostate image registration using feature line parallelization and normalized mutual information.

Post-implant dosimetry for permanent prostate brachytherapy is typically performed using computed tomography (CT) images, for which the clear visualization of soft tissue structures is problematic. Registration of CT and magnetic resonance (MR) image volumes can improve the definition of all structures of interest (soft tissues, bones, and seeds) in the joint image set. In the present paper, we describe a novel two-stage rigid-body registration algorithm that consists of (1) parallelization of straight lines fit to image features running primarily in the superior-inferior (Z) direction, followed by (2) normalized mutual information registration. The first stage serves to fix rotation angles about the anterior-posterior (Y) and left-right (X) directions, and the second stage determines the remaining Z-axis rotation angle and the X, Y, Z translation values. The new algorithm was applied to CT and 1.5T MR (T2-weighted and balanced fast-field echo sequences) axial image sets for three patients acquired four weeks after prostate brachytherapy using 125I seeds. Image features used for the stage 1 parallelization were seed trains in CT and needle tracks and seed voids in MR. Simulated datasets were also created to further investigate algorithm performance. Clinical image volumes were successfully registered using the two-stage approach to within a root-mean-squares (RMS) distance of <1.5 mm, provided that some pubic bone and anterior rectum were included in the registration volume of interest and that no motion artifact was apparent. This level of accuracy is comparable to that obtained for the same clinical datasets using the Procrustes algorithm. Unlike Procrustes, the new algorithm can be almost fully automated, and hence we conclude that its further development for application in post-implant dosimetry is warranted.

Multi-objective optimization in radiotherapy: applications to stereotactic radiosurgery and prostate brachytherapy.

Treatment planning for radiation therapy is a multi-objective optimization process. Here we present a machine intelligent scheme for treatment planning based on multi-objective decision analysis (MODA) and genetic algorithm (GA) optimization. Multi-objective ranking strategies are represented in the L(p) metric under the displaced ideal model. Goal setting, protocol satisficing and fuzzy ranking of objective importance can be incorporated into the decision scheme to assimilate clinical decision making. For distance measures in the L(p) metric, a dynamic gauge function is defined based on the state energy of the decision system, which is assumed to undergo thermodynamic cooling with iteration time. The MODA scheme interacts with a robust GA engine, which adaptively evolves in the multi-modal landscape that defines the treatment plan quality. A conventionally challenging case of stereotactic radiosurgery of a brain lesion was selected for GA optimization. The resulting dose distributions are compared to human-developed plans, which are commonly regarded as clinically relevant and empirically optimal. The GA-optimized plans achieve substantially better sparing of critical normal neuroanatomy surrounding the brain lesion while respecting the preset constraints on tumor dose uniformity. In addition, machine optimization tends to produce novel treatment strategies which complements expert knowledge. The run time for producing an optimal plan is considerably shorter than the typical planning time for human experts, thus GA can also be used to aid the human treatment planning process. In prostate brachytherapy, MODA-GA was specifically applied to non-ideal conditions in which typical surgical uncertainties in seed implant positioning occur, where noisy objectives were introduced into the optimization scheme. The noisy system is found to be manageable by MODA-GA at uncertainty levels corresponding to reasonably proficient surgery teams. In contrast, noisy objectives would be very difficult to explore by human expert planners. Potential use of noisy optimization with time series analysis is being explored for error-corrective computer guidance in the operating room for prostate seed implantation. In conclusion, the combination of MODA and GA optimization offers both a solution to practical treatment planning tasks and the potential for real time applications in radiotherapy.

Healthful radiation.

This title of this article sounds paradoxical to most people because the general public is not fully aware of the many benefits radiation has brought to people's healthcare. Radiation has provided the most effective means of noninvasive diagnosis of many diseases, thus reducing the need for exploratory surgery, at significantly reduced risks. Furthermore, radiotherapy has been effective in treating many diseases without surgical removal of the diseased part. The breast is one excellent example of the benefits of radiation in both diagnosis and treatment with preservation. Yet the public still regards radiation as mysterious and dangerous, while trained experts regard it as beneficial with manageable risks. This article suggests ways of presenting this material to the public in a manner that is interesting and informative.