Development of a geometry‐based respiratory motion– simulating patient model for radiation treatment dosimetry

Zhang, Juying; Xu, George; Shi, Chengyu; Fuß, Martin

doi:10.1120/jacmp.v9i1.2700

Cited by 27 publications

(31 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 4D VIP-Man Chest phantom was used to study external-beam treatment planning for a lung cancer patient [233]. The group later decided to apply the BREP techniques to a more challenging problem and, in 2007, reported the development of a series of phantoms representing a pregnant woman and her fetus at the end of 3-, 6-, and 9-month gestations [109].…”

Section: Brep Phantoms From 2000s To Presentmentioning

confidence: 99%

“…Computational phantoms have been used extensive at RPI for diverse health physics and medical physics applications, including external photon beams from 10 keV to 10 MeV [132,133], external electron beams [134,135], external neutron beam in low energies (10 -9 -20 MeV) and in high energy (20-10,000 MeV) [134,136], external proton beams [137], photon dose to the red bone marrow [174], internal electron dosimetry [138,139], SPECT and PET brain imaging [140], X-ray radiographs [141], X-ray image quality ROC/AUC analysis [142], interventional cardiological examinations [143], adjoint Monte Carlo algorithm for external-beam prostate radiation treatment planning [231], non-target organ doses from proton radiation treatments [145], respiration management in IGRT [233], imaging doses in IGRT [44], kV CBCT and MDCT [146], and time-resolved proton range telescope [147]. More information can be found at the website for Rensselaer Radiation Dosimetry and Measurement Group (http://rrmdg.rpi.edu).…”

Section: Applications Of Computational Phantoms At Rpimentioning

confidence: 99%

See 1 more Smart Citation

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

2013

The Phantoms of Medical and Health Physics

View full text Add to dashboard Cite

Dosimetry for ionizing radiation has to do with the determination of amount and distribution pattern of the energy deposited in a part or parts of the human body from internal or external radiation sources. To protect against occupational exposures, dose limits for radiosensitive organs are recommended by international organizations and are adopted as national regulations. In both diagnostic radiology and nuclear medicine, X-ray photons and gamma rays traverse through body tissues to form images of the anatomy, depositing radiation energy in organs along the pathway via secondary electrons. Accurate radiation dosimetry is essential but also quite challenging for three reasons: (1) there are many diverse exposure scenarios resulting in unique spatial and temporal relationships between the source and human body; (2) an exposure can involve multiple radiation types, each of which is governed by different radiation physics principles, such as photons (X-ray photons, gamma rays, and positrons), electrons, alpha particles, neutrons, and protons; (3) the human body consists of a large number of anatomical structures of diverse shape, composition and density, leading to complex radiation interaction patterns. Since it is inconvenient to place a dosimeter inside the human body, organ dose estimates have been obtained mostly using a physical phantom or a computational phantom that mimics the interior and exterior anatomical features of the human body.Historically, the term phantom was used in most radiological science literature to mean a physical model of the human body. In the radiation protection community, however, the term has also been used to refer to a mathematically defined anatomical model that is distinctly different from a physiologically based model such as that related to respiration or blood flow. In this chapter, the phrases, ''computational phantom'' and ''physical phantom,'' are used to avoid confusion.

show abstract

Section: Brep Phantoms From 2000s To Presentmentioning

confidence: 99%

Section: Applications Of Computational Phantoms At Rpimentioning

confidence: 99%

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

2013

The Phantoms of Medical and Health Physics

View full text Add to dashboard Cite

show abstract

“…Dynamic models of the lungs, the liver and the prostate have been developed [23][24][25][26][27][28][29] and used in radiation therapy applications. [30][31][32][33] Compared with 4DCT, 4D models have a few advantages including better temporal resolution and flexibility of motion pattern change so they may be used in guidance for real time tracking delivery.…”

Section: Introductionmentioning

confidence: 99%

Real time 4D IMRT treatment planning based on a dynamic virtual patient model: Proof of concept

Guo

Shi

2011

Med. Phys.

Self Cite

View full text Add to dashboard Cite

Purpose: To develop a novel four-dimensional (4D) intensity modulated radiation therapy (IMRT) treatment planning methodology based on dynamic virtual patient models. Methods: The 4D model-based planning (4DMP) is a predictive tracking method which consists of two main steps: (1) predicting the 3D deformable motion of the target and critical structures as a function of time during treatment delivery; (2) adjusting the delivery beam apertures formed by the dynamic multi-leaf collimators (DMLC) to account for the motion. The key feature of 4DMP is the application of a dynamic virtual patient model in motion prediction, treatment beam adjustment, and dose calculation. A lung case was chosen to demonstrate the feasibility of the 4DMP. For the lung case, a dynamic virtual patient model (4D model) was first developed based on the patient's 4DCT images. The 4D model was capable of simulating respiratory motion of different patterns. A model-based registration method was then applied to convert the 4D model into a set of deformation maps and 4DCT images for dosimetric purposes. Based on the 4D model, 4DMP treatment plans with different respiratory motion scenarios were developed. The quality of 4DMP plans was then compared with two other commonly used 4D planning methods: maximum intensity projection (MIP) and planning on individual phases (IP). Results: Under regular periodic motion, 4DMP offered similar target coverage as MIP with much better normal tissue sparing. At breathing amplitude of 2 cm, the lung V 20 was 23.9% for a MIP plan and 16.7% for a 4DMP plan. The plan quality was comparable between 4DMP and IP: PTV V 97 was 93.8% for the IP plan and 93.6% for the 4DMP plan. Lung V 20 of the 4DMP plan was 2.1% lower than that of the IP plan and D max to cord was 2.2 Gy higher. Under a real time irregular breathing pattern, 4DMP had the best plan quality. PTV V 97 was 90.4% for a MIP plan, 88.6% for an IP plan and 94.1% for a 4DMP plan. Lung V 20 was 20.1% for the MIP plan, 17.8% for the IP plan and 17.5% for the 4DMP plan. The deliverability of the real time 4DMP plan was proved by calculating the maximum leaf speed of the DMLC. Conclusions: The 4D model-based planning, which applies dynamic virtual patient models in IMRT treatment planning, can account for the real time deformable motion of the tumor under different breathing conditions. Under regular motion, the quality of 4DMP plans was comparable with IP and superior to MIP. Under realistic motion in which breathing amplitude and period change, 4DMP gave the best plan quality of the three 4D treatment planning techniques.

show abstract

“…However, the most advanced computational phantoms are now based on tomographic images or high-resolution color photographs of real patient anatomy and are available in sub-millimeter anatomical detail (Caon 2004, Dimbylow 2005, Fill et al 2004, Xu et al 2000, Zaidi and Xu 2007). In addition, 4D motion, such as motion due to respiration and the beating heart, are now incorporated into many computational phantoms (Garrity et al 2003, Segars 2001, Segars et al 1999, Zhang et al 2008). …”

Section: Introductionmentioning

confidence: 99%

Extension of the NCAT phantom for the investigation of intra-fraction respiratory motion in IMRT using 4D Monte Carlo

McGurk¹,

Seco²,

Riboldi³

et al. 2010

Phys. Med. Biol.

View full text Add to dashboard Cite

The purpose of this work was to create a computational platform for studying motion in intensity modulated radiotherapy (IMRT). Specifically, the non-uniform rational B-spline (NURB) cardiac and torso (NCAT) phantom was modified for use in a four-dimensional Monte Carlo (4D-MC) simulation system to investigate the effect of respiratory-induced intra-fraction organ motion on IMRT dose distributions as a function of diaphragm motion, lesion size and lung density. Treatment plans for four clinical scenarios were designed: diaphragm peak-to-peak amplitude of 1 cm and 3 cm, and two lesion sizes—2 cm and 4 cm diameter placed in the lower lobe of the right lung. Lung density was changed for each phase using a conservation of mass calculation. Further, a new heterogeneous lung model was implemented and tested. Each lesion had an internal target volume (ITV) subsequently expanded by 15 mm isotropically to give the planning target volume (PTV). The PTV was prescribed to receive 72 Gy in 40 fractions. The MLC leaf sequence defined by the planning system for each patient was exported and used as input into the MC system. MC simulations using the dose planning method (DPM) code together with deformable image registration based on the NCAT deformation field were used to find a composite dose distribution for each phantom. These composite distributions were subsequently analyzed using information from the dose volume histograms (DVH). Lesion motion amplitude has the largest effect on the dose distribution. Tumor size was found to have a smaller effect and can be mitigated by ensuring the planning constraints are optimized for the tumor size. The use of a dynamic or heterogeneous lung density model over a respiratory cycle does not appear to be an important factor with a ≤ 0.6% change in the mean dose received by the ITV, PTV and right lung. The heterogeneous model increases the realism of the NCAT phantom and may provide more accurate simulations in radiation therapy investigations that use the phantom. This work further evaluates the NCAT phantom for use as a tool in radiation therapy research in addition to its extensive use in diagnostic imaging and nuclear medicine research. Our results indicate that the NCAT phantom, combined with 4D-MC simulations, is a useful tool in radiation therapy investigations and may allow the study of relative effects in many clinically relevant situations.

show abstract

Development of a geometry‐based respiratory motion– simulating patient model for radiation treatment dosimetry

Cited by 27 publications

References 44 publications

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

Real time 4D IMRT treatment planning based on a dynamic virtual patient model: Proof of concept

Extension of the NCAT phantom for the investigation of intra-fraction respiratory motion in IMRT using 4D Monte Carlo

Contact Info

Product

Resources

About