Background: In order to improve the evaluation of possible rectal toxicity based on the rectal normal tissue complication probability (NTCP), we consider the fractional dependence of the NTCP on the wall thickness (tW) and rectal displacement (RM). Materials and Methods: The two-dimensional NTCP model (NTCP2D) was developed using radiotherapy plans of ten randomly selected patients with prostat...

BACKGROUND Rectal cancer patients that show a pathological complete response (pCR) after neo-adjuvant chemo-radiotherapy, have better prognosis. To increase pCR rates several studies escalate the tumor irradiation dose. However, due to lacking tumor contrast on online imaging techniques, no direct tumor setup can be performed and large boost margins are needed to ensure tumor coverage. The purp...

PURPOSE Hydrogel prostate-rectum spacers, biomaterials placed between the prostate and rectum, continue to gain interest as a method to reduce or limit rectal dose during dose escalated prostate cancer radiation therapy. Because the spacer is initially injected into the perirectal space as a liquid, the final distribution can vary. The purpose of this study was to evaluate hydrogel spacer (Spac...

Figure shows the absolute change in the Dmean for the anal sphincter (left y-axis) and relative change in the V64Gy for the rectal wall (right y-axis) expressed as a function of the relative increase in the homogeneity index HI of the dose distribution in the PTV. Conclusions: By increasing the inhomogeneity of the targeted dose to the PTV in prostate RT plans the dose delivered to the rectal w...

The inability to avoid rectal wall irradiation has been a limiting factor in prostate cancer treatment planning. Treatment planners must not only consider the maximum dose that the rectum receives throughout a course of treatment, but also the dose that any volume of the rectum receives. As treatment planning techniques have evolved and prescription doses have escalated, limitations of rectal d...

A novel FDA approved in vivo dosimetry device system using plastic scintillating detectors placed in an endorectal balloon to provide real-time in vivo dosimetry for prostatic rectal interface was tested for use with stereotactic body radiotherapy (SBRT). The system was used for the first time ever to measure dose during linear accelerator based SBRT. A single patient was treated with a total d...

BACKGROUND MOSFET dosimetry is a method that has been used to measure in-vivo doses during brachytherapy treatments and during linac based radiotherapy treatment. Rectal displacement devices (RDDs) allow for safe dose escalation for prostate cancer treatment. This study used dual MOSkin detectors to assess real-time in vivo rectal wall dose in patients with an RDD in place during a high dose pr...

High-dose rate endorectal brachytherapy (HDR-EBT) is mainly used as a palliative treatment modality. In this paper, we compare dosimetry distributions for a single-channel catheter (Miami) applicator with distributions of the inflatable multichannel (Novi Sad) endorectal applicator. The comparisons were made with respect to dose coverage to the clinical tumor volume as well as to the bladder, r...

the effect of intracerebroventricular injections of prostaglandins e2 and f2a was studied on the rectal temperature of sheep. pge2 but not pgf2a at the same dose of 50mg elevated the 1h post-injection of rectal temperature. pge2 but not pgf2a at the same dose of 100mg increased 3.5 and 2h post-injection of rectal temperature, respectively. elavation of rectal temperature following pge2 and pgf2...

PURPOSE To describe dose-volume values with the use of water alone vs. a rectal balloon (RB) for the treatment of prostate cancer with proton therapy. MATERIALS AND METHODS We analyzed 30 proton plans for 15 patients who underwent CT and MRI scans with an RB or water alone. Simulation was performed with a modified MRI endorectal coil and an RB with 100 mL of water or water alone. Doses of 78-...