Commissioning of the discrete spot scanning proton beam delivery system at the University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston

Gillin, Michael; Sahoo, Narayan; Bues, Martin; Ciangaru, G.; Sawakuchi, Gabriel O.; Poenisch, Falk; Arjomandy, B.; Martin, C.J.; Titt, Uwe; Suzuki, Kazumichi; Smith, Alfred R.; Zhu, Xiaorong Ronald

doi:10.1118/1.3259742

Cited by 247 publications

(293 citation statements)

References 9 publications

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“…The in‐air proton spot size of our beam lines is smaller than those of the Hitachi system reported by Gillin et al (35) Furthermore, because the built‐in posterior bolus and U‐shaped anterior and lateral bolus are closer to the patient surface than range shifters mounted on the PBS nozzle, the spot size incident on the patient is smaller than systems that use nozzle‐mounted range shifters. Therefore, conclusions drawn from this study may not be applicable to other beam lines.…”

Section: Discussionmentioning

confidence: 61%

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Lin

Kang

Huang

et al. 2015

J Applied Clin Med Phys

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The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ±3% uncertainty in stopping power and ±3 mm uncertainty in patient setup in each direction, were used to create 8×12×10=960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p‐values <0.05, with the exception of the heart V45 (p=0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion‐related uncertainties is essential.PACS number: 87.55.D

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Section: Discussionmentioning

confidence: 61%

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Lin

Kang

Huang

et al. 2015

J Applied Clin Med Phys

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“…As shown in the study by Gillin et al, (20) they could also be used to measure absorbed dose. Regarding the measurement of relative dose distributions, we identified the following applications for the detectors under investigation:

Bragg peak chamber: is the current clinical standard for acquisition of pristine depth dose curves (e.g., TPS commissioning) or as reference depth‐dose curve for Giraffe (with a maximum energy beam).

…”

Section: Discussionmentioning

confidence: 95%

Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Bäumer

Koska

Lambert

et al. 2015

J Applied Clin Med Phys

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Acquisition of quasi‐monoenergetic ("pristine") depth‐dose curves is an essential task in the frame of commissioning and quality assurance of a proton therapy treatment head. For pencil beam scanning delivery modes this is often accomplished by measuring the integral ionization in a plane perpendicular to the axis of an unscanned beam. We focus on the evaluation of three integral detectors: two of them are plane‐parallel ionization chambers with an effective radius of 4.1 cm and 6.0 cm, respectively, mounted in a scanning water phantom. The third integral detector is a 6.0 cm radius multilayer ionization chamber. The experimental results are compared with the corresponding measurements under broad field conditions, which are performed with a small radius plane‐parallel chamber and a small radius multilayer ionization chamber. We study how a measured depth‐dose curve of a pristine proton field depends on the detection device, by evaluating the shape of the depth‐dose curve, the relative charge collection efficiency, and intercomparing measured ranges. Our results show that increasing the radius of an integral chamber from 4.1 cm to 6.0 cm increases the collection efficiency by 0%–3.5% depending on beam energy and depth. Ranges can be determined by the large electrode multilayer ionization chamber with a typical uncertainty of 0.4 mm on a routine basis. The large electrode multilayer ionization chamber exhibits a small distortion in the Bragg Peak region. This prohibits its use for acquisition of base data, but is tolerable for quality assurance. The good range accuracy and the peak distortion are characteristics of the multilayer ionization chamber design, as shown by the direct comparison with the small electrode counterpart.PACS number: 87.55.Qr

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“…For a majority of the current commercial proton beam systems, the minimum proton beam energy ranges from 70 to 100 MeV which is about 4.1–7.5 cm in water‐equivalent thickness (WET). In order to treat superficial target volume such as patients with head and neck cancer (HNC), and brain tumors, a range shifter (RS) is normally needed to attenuate the proton beam energy 3, 4, 5…”

Section: Introductionmentioning

confidence: 99%

“…The RS which is normally composed of slab of plastics such as acrylonitrile butadiene styrene (ABS) and polyethylene 3, 4, 5 which broadens the proton beams due to the secondary scattering 6. In order to reduce the scattering and keep a smaller spot size, the air gap between the gantry nozzle and patient's skin must be reduced.…”

Section: Introductionmentioning

confidence: 99%

Redefine the role of range shifter in treating bilateral head and neck cancer in the era of Intensity Modulated Proton Therapy

Ding

Qin

et al. 2018

J Applied Clin Med Phys

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Commissioning of the discrete spot scanning proton beam delivery system at the University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston

Abstract: The dosimetric parameters of the discrete spot scanning proton beam have been measured as part of the clinical commissioning program, and the machine is found to function in a safe manner, making it suitable for patient treatment.

Cited by 247 publications

References 9 publications

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Beam‐specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors

Evaluation of detectors for acquisition of pristine depth‐dose curves in pencil beam scanning

Redefine the role of range shifter in treating bilateral head and neck cancer in the era of Intensity Modulated Proton Therapy

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