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Title: SU-F-T-196: Hypo-Fractionation with Intensity Modulated Proton Therapy for Unilateral Metallic Prosthesis Prostate Cancer Patients

Abstract

Purpose: The purpose of this study is to investigate the dosimetric feasibility of hypo-fractionated intensity modulated proton therapy (IMPT) for unilateral metallic prosthesis prostate cancer patients based on proton collaborative group (PCG)-GU002-10 (NCT01230866) protocol criteria. Methods: A total of five unilateral metallic prosthesis prostate cancer cases were included in this retrospective study. For each case, IMPT plans were generated for treatment to be delivered with 7.6 Gy[RBE] per fraction in 5 fractions per week for a total dose of 38 Gy(RBE). Each plan was generated using two anterior-oblique beams and one lateral beam. Treatment plans were optimized with an objective meeting PCG-GU002-10 (NCT01230866) protocol criteria: (i) planning target volume (PTV): D99.5% > 36.1 Gy[RBE], (ii) rectum: V24 < 35%, V33.6 < 10%, (iii) bladder: V39 < 8 cc, and (iv) femoral head: V23 < 1cc. Results: All five cases satisfied PTV D99.5% (average=36.82 Gy[RBE]; range, 36.36–37.13 Gy[RBE]). PTV D95% ranged from 36.66 Gy[RBE] to 38.65 Gy[RBE] and PTV V100 ranged from 95.47% to 97.95%. For the rectum, V24 was less than 35% (average=14.07 Gy[RBE]; range, 6.22–18.42%, whereas V33.6 Gy[RBE] was less than 10% (average=6.83; range, 3.06 – 9.15%). Rectal mean dose ranged from 4.22 Gy[RBE] to 9.97 Gy[RBE]. For themore » bladder, V39 was found to be less than 8 cc (average=3.69 cc; range, 0.19–7.68 cc). Bladder mean dose ranged from 4.22 Gy[RBE] to 18.83 Gy[RBE]. For the femoral head, V23 was 0 in all five cases. Conclusion: All five unilateral metallic prosthesis prostate cancer IMPT plans generated with one lateral and two anterior-oblique beams satisfied the dosimetric criteria of PCG-GU002-10 (NCT01230866) protocol.« less

Authors:
;  [1];  [2];  [3];  [4];  [5]
  1. McLaren Proton Therapy Center, Karmanos Cancer Institute at McLaren-Flint, Flint, MI (United States)
  2. Procure Proton Therapy Center, Oklahoma City, OK (United States)
  3. University of Cincinnati Medical Center, Liberty Township, OH (United States)
  4. 21st Century Oncology, Estero, FL (United States)
  5. Vantage Oncology, West Hills, CA (United States)
Publication Date:
OSTI Identifier:
22648813
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BLADDER; NEOPLASMS; PATIENTS; PLANNING; PROSTATE; PROSTHESES; PROTON BEAMS; RADIATION DOSES; RADIOTHERAPY; RBE; RECTUM

Citation Formats

Rana, S, Park, S, Zheng, Y, Zhang, Y, Pokharel, and Cheng, C. SU-F-T-196: Hypo-Fractionation with Intensity Modulated Proton Therapy for Unilateral Metallic Prosthesis Prostate Cancer Patients. United States: N. p., 2016. Web. doi:10.1118/1.4956333.
Rana, S, Park, S, Zheng, Y, Zhang, Y, Pokharel, & Cheng, C. SU-F-T-196: Hypo-Fractionation with Intensity Modulated Proton Therapy for Unilateral Metallic Prosthesis Prostate Cancer Patients. United States. doi:10.1118/1.4956333.
Rana, S, Park, S, Zheng, Y, Zhang, Y, Pokharel, and Cheng, C. Wed . "SU-F-T-196: Hypo-Fractionation with Intensity Modulated Proton Therapy for Unilateral Metallic Prosthesis Prostate Cancer Patients". United States. doi:10.1118/1.4956333.
@article{osti_22648813,
title = {SU-F-T-196: Hypo-Fractionation with Intensity Modulated Proton Therapy for Unilateral Metallic Prosthesis Prostate Cancer Patients},
author = {Rana, S and Park, S and Zheng, Y and Zhang, Y and Pokharel and Cheng, C},
abstractNote = {Purpose: The purpose of this study is to investigate the dosimetric feasibility of hypo-fractionated intensity modulated proton therapy (IMPT) for unilateral metallic prosthesis prostate cancer patients based on proton collaborative group (PCG)-GU002-10 (NCT01230866) protocol criteria. Methods: A total of five unilateral metallic prosthesis prostate cancer cases were included in this retrospective study. For each case, IMPT plans were generated for treatment to be delivered with 7.6 Gy[RBE] per fraction in 5 fractions per week for a total dose of 38 Gy(RBE). Each plan was generated using two anterior-oblique beams and one lateral beam. Treatment plans were optimized with an objective meeting PCG-GU002-10 (NCT01230866) protocol criteria: (i) planning target volume (PTV): D99.5% > 36.1 Gy[RBE], (ii) rectum: V24 < 35%, V33.6 < 10%, (iii) bladder: V39 < 8 cc, and (iv) femoral head: V23 < 1cc. Results: All five cases satisfied PTV D99.5% (average=36.82 Gy[RBE]; range, 36.36–37.13 Gy[RBE]). PTV D95% ranged from 36.66 Gy[RBE] to 38.65 Gy[RBE] and PTV V100 ranged from 95.47% to 97.95%. For the rectum, V24 was less than 35% (average=14.07 Gy[RBE]; range, 6.22–18.42%, whereas V33.6 Gy[RBE] was less than 10% (average=6.83; range, 3.06 – 9.15%). Rectal mean dose ranged from 4.22 Gy[RBE] to 9.97 Gy[RBE]. For the bladder, V39 was found to be less than 8 cc (average=3.69 cc; range, 0.19–7.68 cc). Bladder mean dose ranged from 4.22 Gy[RBE] to 18.83 Gy[RBE]. For the femoral head, V23 was 0 in all five cases. Conclusion: All five unilateral metallic prosthesis prostate cancer IMPT plans generated with one lateral and two anterior-oblique beams satisfied the dosimetric criteria of PCG-GU002-10 (NCT01230866) protocol.},
doi = {10.1118/1.4956333},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}
  • Purpose: The main purpose of this study is to investigate the optimum oblique-beam arrangement for bilateral metallic prosthesis prostate cancer treatment in pencil beam scanning (PBS) proton therapy. Methods: A computed tomography dataset of bilateral metallic prosthesis prostate cancer case was selected for this retrospective study. A total of four beams (rightanterior- oblique [RAO], left-anterior-oblique [LAO], left-posterior-oblique [LPO], and right-posterior-oblique [RPO]) were selected for treatment planning. PBS plans were generated using multi-field-optimization technique for a total dose of 79.2 Gy[RBE] to be delivered in 44 fractions. Specifically, five different PBS plans were generated based on 2.5% ± 2 mm rangemore » uncertainty using five different beam arrangements (i)LAO+RAO+LPO+RPO, (ii)LAO+RAO, (iii)LPO+RPO, (iv)RAO+LPO, and (v)LAO+RPO. Each PBS plan was optimized by applying identical dose-volume constraints to the PTV, rectum, and bladder. Treatment plans were then compared based on the dose-volume histograms results. Results: The PTV coverage was found to be greater than 99% in all five plans. The homogeneity index (HI) was found to be almost identical (range, 0.03–0.04). The PTV mean dose was found to be comparable (range, 81.0–81.1 Gy[RBE]). For the rectum, the lowest mean dose (8.0 Gy[RBE]) and highest mean dose (31.1 Gy[RBE]) were found in RAO+LAO plan and LPO+RPO plan, respectively. LAO+RAO plan produced the most favorable dosimetric results of the rectum in the medium-dose region (V50) and high-dose region (V70). For the bladder, the lowest (5.0 Gy[RBE]) and highest mean dose (10.3 Gy[RBE]) were found in LPO+RPO plan and RAO+LAO plan, respectively. Other dosimetric results (V50 and V70) of the bladder were slightly better in LPO+RPO plan than in other plans. Conclusion: Dosimetric findings from this study suggest that two anterior-oblique proton beams arrangement (LAO+RAO) is a more favorable option with the possibility of reducing rectal dose significantly while maintaining comparable target coverage and acceptable bladder dose.« less
  • Purpose: To examine how much lifetime attributable risk (LAR) as an in silico surrogate marker of radiation-induced secondary cancer would be lowered by using proton beam therapy (PBT) in place of intensity modulated x-ray therapy (IMXT) in pediatric patients. Methods: From 242 pediatric patients with cancers who were treated with PBT, 26 patients were selected by random sampling after stratification into four categories: a) brain, head, and neck, b) thoracic, c) abdominal, and d) whole craniospinal (WCNS) irradiation. IMXT was re-planned using the same computed tomography and region of interest. Using dose volume histogram (DVH) of PBT and IMXT, themore » LAR of Schneider et al. was calculated for the same patient. The published four dose-response models for carcinoma induction: i) full model, ii) bell-shaped model, iii) plateau model, and ix) linear model were tested for organs at risk. In the case that more than one dose-response model was available, the LAR for this patient was calculated by averaging LAR for each dose-response model. Results: Calculation of the LARs of PBT and IMXT based on DVH was feasible for all patients. The mean±standard deviation of the cumulative LAR difference between PBT and IMXT for the four categories was a) 0.77±0.44% (n=7, p=0.0037), b) 23.1±17.2%,(n=8, p=0.0067), c) 16.4±19.8% (n=8, p=0.0525), and d) 49.9±21.2% (n=3, p=0.0275, one tailed t-test), respectively. The LAR was significantly lower by PBT than IMXT for the the brain, head, and neck region, thoracic region, and whole craniospinal irradiation. Conclusion: In pediatric patients who had undergone PBT, the LAR of PBT was significantly lower than the LAR of IMXT estimated by in silico modeling. This method was suggested to be useful as an in silico surrogate marker of secondary cancer induced by different radiotherapy techniques. This research was supported by the Translational Research Network Program, JSPS KAKENHI Grant No. 15H04768 and the Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, founded by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.« less
  • Megavoltage photon intensity-modulated radiation therapy (IMRT) is typically used in the treatment of prostate cancer at our institution. Approximately 1% to 2% of patients with prostate cancer have hip prostheses. The presence of the prosthesis usually complicates the planning process because of dose perturbation around the prosthesis, radiation attenuation through the prosthesis, and the introduction of computed tomography artifacts in the planning volume. In addition, hip prostheses are typically made of materials of high atomic number, which add uncertainty to the dosimetry of the prostate and critical organs in the planning volume. When the prosthesis is bilateral, treatment planning ismore » further complicated because only a limited number of beam angles can be used to avoid the prostheses. In this case study, we will report the observed advantages of using noncoplanar beams in the delivery of IMRT to a prostate cancer patient with bilateral hip prostheses. The treatment was planned for 75.6 Gy using a 7-field coplanar approach and a noncoplanar arrangement, with all fields avoiding entrance though the prostheses. Our results indicate that, compared with the coplanar plan, the noncoplanar plan delivers the prescribed dose to the target with a slightly better conformality and sparing of rectal tissue versus the coplanar plan.« less
  • Purpose: Recurrent chordomas are difficult to control locally. This dosimetric study investigates the feasibility of dose escalation to hypoxic regions, visualized on FMISO-PET, while respecting the dose constraints to the neighboring normal tissues/organs. We propose to deliver a higher dose to the areas of hypoxia (84.5Gy) using IMPT with the goal of improving local control. Methods: We currently have four patients with hypoxic subvolumes (HSV) greater than 10cc from the FMISO-PET image. The HSV was delineated based on the standardized uptake values of greater than 1.4 times of the muscle mean. Gross tumor volume (GTV) was delineated using planning CTmore » with the assistance of MRI fusion. The dose scheme is 50.4Gy RBE to CTV in 1.8Gy fractions, followed by an integrated boost of 27.0Gy RBE to GTV in 1.8Gy fractions and 34.5Gy RBE to HSV in 2.3Gy fractions. IMPT integrated boost plans were optimized with multi-criteria optimization (MCO). Posterior-anterior beam angles were used for these plans. We also propose using two posterior oblique fields to boost HSV to spare the skin folding. A medium spot size with 8mm to 15 mm (σ) in air at isocenter with energies from 220 MeV down to 90 MeV was used. Aperture was used for the medium spot size. A small spot size of 2.5 mm to 4.5 mm (σ) in air at isocenter with energies from 240 MeV down to 70 MeV was also proposed. Target coverage and dose to OARs were evaluated. Results: For the sacral chordoma patient that has been planned, the target homogeneity index is 3.2% for HSV, 55.9% for CTV and 11.9% for GTV. The max dose is 77GyRBE to rectum, 86.2GyRBE to sacral nerves and 73.9GyRBE to cauda equina. Conclusion: IMPT with integrated high dose boost to HSV determined from FMISO PET image is feasible. OAR dose constraints were met.« less
  • Purpose: Clinical implementations of adaptive radiotherapy (ART) are limited mainly by the requirement of delivery QA (DQA) prior to the treatment. Small segment size and small segment MU are two dominant factors causing failures of DQA. The aim of this project is to explore the feasibility of ART treatment without DQA by using a partial optimization approach. Methods: A retrospective simulation study was performed on two prostate cancer patients treated with SMLC-IMRT. The prescription was 180cGx25 fractions with daily CT-on-rail imaging for target alignment. For each patient, seven daily CTs were selected randomly across treatment course. The contours were deformablelymore » transferred from the simulation CT onto the daily CTs and modified appropriately. For each selected treatment, dose distributions from original beams were calculated on the daily treatment CTs (DCT plan). An ART plan was also created by optimizing the segmental MU only, while the segment shapes were preserved and the minimum MU constraint was respected. The overlaps, between PTV and the rectum, between PTV and the bladder, were normalized by the PTV volume. This ratio was used to characterize the difficulty of organs-at-risk (OAR) sparing. Results: Comparing to the original plan, PTV coverage was compromised significantly in DCT plans (82% ± 7%) while all ART plans preserved PTV coverage. ART plans showed similar OAR sparing as the original plan, such as V40Gy=11.2cc (ART) vs 11.4cc (original) for the rectum and D10cc=4580cGy vs 4605cGy for the bladder. The sparing of the rectum/bladder depends on overlap ratios. The sparing in ART was either similar or improved when overlap ratios in treatment CTs were smaller than those in original plan. Conclusion: A partial optimization method is developed that may make the real-time ART feasible on selected patients. Future research is warranted to quantify the applicability of the proposed method.« less