A study on prostate movement and dosimetric variation because of bladder and rectum volumes changes during the course of image-guided radiotherapy in prostate cancer

Gurjar, Om Prakash; Arya, Rajeev; Goyal, Harsh

doi:10.1016/j.prnil.2019.12.003

Cited by 10 publications

(9 citation statements)

References 17 publications

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“…We have observed pronounced intra-and intersubject variation of the filling status of the rectum, as reported in Table 1: in our dataset of 17 patients and 85 fractions, the volumes of the rectum and bladder are 83 ± 39cm 3 and 278 ± 162cm 3 respectively, compared to 50 ± 10cm 3 and 401 ± 130cm 3 across 30 patients without surgery. 33 Furthermore, our data exhibit air pockets with much higher frequency and severity compared to typical male pelvic imaging. This is possibly caused by postsurgical side effects such as abdominal bloating, diarrhea, or constipation in postprostatec-tomy patients, 34 and postsurgery abnormal bowel movement makes it harder to comply to imaging protocols.…”

Section: Discussionmentioning

confidence: 57%

“…Our observation agrees with the reported assessment for postprostatectomy patients that the daily variations of the rectum and bladder filling status are larger than the patients with intact prostate. 33,35,36 The composition with artifacts caused by severe air bubbles further challenges rectum segmentation 37 and also leads to high uncertainty in human contours used as training labels.…”

Section: Discussionmentioning

confidence: 99%

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Ensemble learning and tensor regularization for cone‐beam computed tomography‐based pelvic organ segmentation

et al. 2022

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Purpose Cone‐beam computed tomography (CBCT) is a widely accessible low‐dose imaging approach compatible with on‐table patient anatomy observation for radiotherapy. However, its use in comprehensive anatomy monitoring is hindered by low contrast and low signal‐to‐noise ratio and a large presence of artifacts, resulting in difficulty in identifying organ and structure boundaries either manually or automatically. In this study, we propose and develop an ensemble deep‐learning model to segment post‐prostatectomy organs automatically. Methods We utilize the ensemble logic in various modules during the segmentation process to alleviate the impact of low image quality of CBCT. Specifically, (1) semantic attention was obtained from an ensemble 2.5D You‐only‐look‐once detector to consistently define regions of interest, (2) multiple view‐specific two‐stream 2.5D segmentation networks were developed, using auxiliary high‐quality CT data to aid CBCT segmentation, and (3) a novel tensor‐regularized ensemble scheme was proposed to aggregate the estimates from multiple views and regularize the spatial integrity of the final segmentation. Results A cross‐validation study achieved Dice similarity coefficient and mean surface distance of 0.779 ±$\pm$ 0.069 and 2.895 ±$\pm$ 1.496 mm for the rectum, and 0.915 ±$\pm$ 0.055 and 1.675 ±$\pm$ 1.311 mm for the bladder. Conclusions The proposed ensemble scheme manages to enhance the geometric integrity and robustness of the contours derived from CBCT with light network components. The tensor regularization approach generates organ results conforming to anatomy and physiology, without compromising typical quantitative performance in Dice similarity coefficient and mean surface distance, to support further clinical interpretation and decision making.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Ensemble learning and tensor regularization for cone‐beam computed tomography‐based pelvic organ segmentation

et al. 2022

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“…Gurjar et al reported about prostate movement and dosimetric variations because of bladder and rectum volume changes using daily cone-beam CT(CBCT). They concluded that bladder and rectum volume affects the position of the prostate, but no data was shown to substantiate the correlation [25]. This makes us believe that the correlation between UV changes and prostate movement is still not proven and that confounding factors such as PV could have affected the correlation.…”

Section: Discussionmentioning

confidence: 95%

The Impact of Daily Urinary Volume Variations and Prostate Volume on Prostate Position During Radiotherapy

Nishioka¹,

Hashimoto²,

Abe³

et al. 2020

Preprint

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BackgroundDaily variations in bladder volumes are thought to be a major cause of prostate position changes during radiotherapy, however, the impact of such changes on prostate position is not fully established. We hypothesized that prostate volume (PV) could also be related to the susceptibility of prostate movement to changes in urinary volume (UV). The purpose of this study is to investigate the impact of daily UV variations and PV on the prostate position during radiotherapy.MethodsA total of 268 treatment sessions in 12 consecutive prostate cancer patients who were treated with proton beam therapy in our hospital were retrospectively analyzed. All patients were instructed to void urine and feces one hour before the treatment and the UV was measured by a portable ultrasound device just before the treatment. After the positional registration based on bone structure, the prostate positional difference from the planned position was measured using fiducial markers in the prostate and a real-time tumor tracking system. The measurements were for the differences in the left-right (LR), cranial-caudal (CC), and anterior-posterior (AP) directions. The PV was measured by ultrasound imaging before every treatment. The impact of the UV variations on the prostate position was evaluated by the linear mixed effect model, and including PV (<20ml and ≥20ml) as covariates. ResultsThere was significant movement of the prostate in the posterior direction with increasing UV in patients with PV ≥ 20 ml (p=0.04, estimated coefficient of regression -0.436 mm/100ml, 95% CI from -0.854 to -0.018). However, there was no significant correlation between UV changes and movement of the prostate in either of the LR, CC, or AP directions in all cases and patients with PV < 20 ml.ConclusionsOur results suggest that the increase of UV could result in posterior prostate movement in patients with prostatic hyperplasia, however, the clinical impact is thought to be small. There is however a need for further research to identify other factors that could affect the daily changes in prostate position as well as a need for a more ideal preparation protocol to improve the reproducibility of the treatment-planning CT.

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“…PCa is a common cancer that mainly occurs in the elderly, 8 one of the leading causes of death in men in the world. 9 , 10 Efforts are being made to overcome it by applying AI technology.…”

Section: Introductionmentioning

confidence: 99%

Dr. Answer AI for prostate cancer: Intention to use, expected effects, performance, and concerns of urologists

Rho

Park

Moon

et al. 2022

Prostate International

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A study on prostate movement and dosimetric variation because of bladder and rectum volumes changes during the course of image-guided radiotherapy in prostate cancer

Cited by 10 publications

References 17 publications

Ensemble learning and tensor regularization for cone‐beam computed tomography‐based pelvic organ segmentation

Ensemble learning and tensor regularization for cone‐beam computed tomography‐based pelvic organ segmentation

The Impact of Daily Urinary Volume Variations and Prostate Volume on Prostate Position During Radiotherapy

Dr. Answer AI for prostate cancer: Intention to use, expected effects, performance, and concerns of urologists

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