Dose variation during hypofractionated image-guided radiotherapy for prostate cancer: Planned versus delivered

Murthy, Vedang; Shukla, Pragya; Adurkar, Pranjal; Master, Zubin; Mahantshetty, Umesh; Shrivastava, Shyam K.

doi:10.4103/0973-1482.82920

Cited by 15 publications

(12 citation statements)

References 28 publications

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“…Several studies have confirmed differences between planned and delivered doses to the rectum. 2,6,7,10,11 These early data support the hypothesis that accumulated dose ( D A ) to the rectum over the course of treatment differs from the planned dose in some patients. Development of methods to accurately estimate D A is critical for a better understanding of the relationship between dose and effect.…”

supporting

confidence: 57%

Random variation in rectal position during radiotherapy for prostate cancer is two to three times greater than that predicted from prostate motion

Scaife

Harrison²,

Romanchikova³

et al. 2014

BJR

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Objective:Radiotherapy for prostate cancer does not explicitly take into account daily variation in the position of the rectum. It is important to accurately assess accumulated dose (DA) to the rectum in order to understand the relationship between dose and toxicity. The primary objective of this work was to quantify systematic (Σ) and random (σ) variation in the position of the rectum during a course of prostate radiotherapy.Methods:The rectum was manually outlined on the kilo-voltage planning scan and 37 daily mega-voltage image guidance scans for 10 participants recruited to the VoxTox study. The femoral heads were used to produce a fixed point to which all rectal contours were referenced.Results:Σ [standard deviation (SD) of means] between planning and treatment was 4.2 mm in the anteroposterior (AP) direction and 1.3 mm left–right (LR). σ (root mean square of SDs) was 5.2 mm AP and 2.7 mm LR. Superior–inferior variation was less than one slice above and below the planning position.Conclusion:Our results for Σ are in line with published data for prostate motion. σ, however, was approximately twice as great as that seen for prostate motion. This suggests that DA may differ from planned dose in some patients treated with radiotherapy for prostate cancer.Advances in knowledge:This work is the first to use daily imaging to quantify Σ and σ of the rectum in prostate cancer. σ was found to be greater than published data, providing strong rationale for further investigation of individual DA.

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supporting

confidence: 57%

Random variation in rectal position during radiotherapy for prostate cancer is two to three times greater than that predicted from prostate motion

Scaife

Harrison²,

Romanchikova³

et al. 2014

BJR

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“…The need for adaptive radiation therapy for prostate cancer due to inter-and intrafraction motion is well documented in the literature. (33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43) We applied a known deformation in the ImSimQA to mimic a distended rectum and introduce rectal gas in the synthetically deformed image. This, in turn, deforms the prostate, as routinely seen in prostate IGRT.…”

Section: B Clinical Rationale and Description Of Applied Known Deformentioning

confidence: 99%

A framework for deformable image registration validation in radiotherapy clinical applications

Varadhan

Karangelis²,

Krishnan

et al. 2013

J Applied Clin Med Phys

124

147

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Quantitative validation of deformable image registration (DIR) algorithms is extremely difficult because of the complexity involved in constructing a deformable phantom that can duplicate various clinical scenarios. The purpose of this study is to describe a framework to test the accuracy of DIR based on computational modeling and evaluating using inverse consistency and other methods. Three clinically relevant organ deformations were created in prostate (distended rectum and rectal gas), head and neck (large neck flexion), and lung (inhale and exhale lung volumes with variable contrast enhancement) study sets. DIR was performed using both B‐spline and diffeomorphic demons algorithms in the forward and inverse direction. A compositive accumulation of forward and inverse deformation vector fields was done to quantify the inverse consistency error (ICE). The anatomical correspondence of tumor and organs at risk was quantified by comparing the original RT structures with those obtained after DIR. Further, the physical characteristics of the deformation field, namely the Jacobian and harmonic energy, were computed to quantify the preservation of image topology and regularity of spatial transformation obtained in DIR. The ICE was comparable in prostate case but the B‐spline algorithm had significantly better anatomical correspondence for rectum and prostate than diffeomorphic demons algorithm. The ICE was 6.5 mm for demons algorithm for head and neck case when compared to 0.7 mm for B‐spline. Since the induced neck flexion was large, the average Dice similarity coefficient between both algorithms was only 0.87, 0.52, 0.81, and 0.67 for tumor, cord, parotids, and mandible, respectively. The B‐spline algorithm accurately estimated deformations between images with variable contrast in our lung study, while diffeomorphic demons algorithm led to gross errors on structures affected by contrast variation. The proposed framework offers the application of known deformations on any image datasets, to evaluate the overall accuracy and limitations of a DIR algorithm used in radiation oncology. The evaluation based on anatomical correspondence, physical characteristics of deformation field, and image characteristics can facilitate DIR verification with the ultimate goal of implementing adaptive radiotherapy. The suitability of application of a particular evaluation metric in validating DIR is dependent on the clinical deformation observed.PACS numbers: 87.57 nj, 87.55‐x,87.55 Qr

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“…Çalışmalarda, prostat ışınlamasında tedavi öncesi günlük CBCT değer-lendirmesi ile mesane ve rektumun aldığı dozların planlamada kabul edilen dozlardan anlamlı olarak farklı olduğu gösterilmiştir. [29,30] Kliniğimizde de 2009 yılından itibaren prostat kanserli olgularda kV-CBCT cihazları ile görüntü kılavuzluğunda yoğunluk ayarlı radyoterapi uygulanmaktadır. Çalışmamızda, kV-CBCT rehberliğin-de uygulanan ortanca 76 Gy IMRT ile ciddi erken yan etki düzeyi çok düşüktür.…”

Section: Discussionunclassified

Acute toxicity in prostate carcinoma patients treated with kV-CBCT guided IMRT/VMAT

Özdemir¹

2014

TJ Oncol

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obJecTIveSTo evaluate acute toxicity of image guided IMRT/VMAT in prostate carcinoma patients. MeTHodSAcute toxicities of 101 prostate carcinoma patients, treated with radical radiotherapy were evaluated. Prostate, prostate and seminal vesicles, and pelvic lymph nodes were enrolled into the treatment volume in 50, 40 and 11cases respectively. All patients were planned with Eclipse treatment planning system using dynamic IMRT/ VMAT. The median doses to the planning target volumes of prostate, seminal vesicles and pelvic lymphatics were 76Gy, 56Gy and 54Gy respectively, delivered simultaneously. All patients were observed per week during radiotherapy and at 1st and 3rd month following completion of therapy. Acute toxicities were graded according to the RTOG scoring criteria. reSULTSGrade 2 and 1genitourinary acute toxicity were observed in 3 and 57 patients, respectively. Grade1 gastrointestinal toxicity was detected in 15 patients, 3 patients developed grade1 skin reaction. Grade 1 leukopenia was detected in 2 cases. No grade 3-4 toxicity was observed. coNcLUSIoNIn prostate cancer, higher doses radiotherapy with kV-CBCT guided IMRT/VMAT technique was given more accurately and well tolerated. Expected side effects depending on size of irradiated volume with pelvic radiotherapy, were not observed.

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Dose variation during hypofractionated image-guided radiotherapy for prostate cancer: Planned versus delivered

Abstract: This study demonstrates the usefulness of daily soft tissue image guidance in negating the effects of physiological variation of the rectum and bladder on the dose delivered to the prostate.

Cited by 15 publications

References 28 publications

Random variation in rectal position during radiotherapy for prostate cancer is two to three times greater than that predicted from prostate motion

Random variation in rectal position during radiotherapy for prostate cancer is two to three times greater than that predicted from prostate motion

A framework for deformable image registration validation in radiotherapy clinical applications

Acute toxicity in prostate carcinoma patients treated with kV-CBCT guided IMRT/VMAT

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