Supine craniospinal irradiation in pediatric patients by proton pencil beam scanning

Farace, Paolo; Bizzocchi, Nicola; Righetto, Roberto; Fellin, F.; Fracchiolla, F.; Lorentini, Stefano; Widesott, L.; Algranati, Carlo; Rombi, Barbara; Vennarini, Sabina; Amichetti, Maurizio; Schwarz, Marco

doi:10.1016/j.radonc.2017.02.008

Cited by 38 publications

(25 citation statements)

References 28 publications

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“…Furthermore, the effect of patient (re)positioning uncertainties on the dose distribution has not been taken into account in this analysis. In fact, one technique might be more robust than another resulting in smaller detrimental effects on the ideal static dose distribution calculated by the treatment planning system [49][50][51]. Comparing the robustness of the different techniques is part of a future work.…”

Section: Discussionmentioning

confidence: 99%

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group)

et al. 2018

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Purpose: Conventional techniques (3D-CRT) for craniospinal irradiation (CSI) are still widely used. Modern techniques (IMRT, VMAT, TomoTherapy V R , proton pencil beam scanning [PBS]) are applied in a limited number of centers. For a 14-year-old patient, we aimed to compare dose distributions of five CSI techniques applied across Europe and generated according to the participating institute protocols, therefore representing daily practice. Material and methods: A multicenter (n ¼ 15) dosimetric analysis of five different techniques for CSI (3D-CRT, IMRT, VMAT, TomoTherapy V R , PBS; 3 centers per technique) was performed using the same patient data, set of delineations and dose prescription (36.0/1.8 Gy). Different treatment plans were optimized based on the same planning target volume margin. All participating institutes returned their best treatment plan applicable in clinic. Results: The modern radiotherapy techniques investigated resulted in superior conformity/homogeneity-indices (CI/HI), particularly in the spinal part of the target (CI: 3D-CRT:0.3 vs. modern:0.6; HI: 3D-CRT:0.2 vs. modern:0.1), and demonstrated a decreased dose to the thyroid, heart, esophagus and pancreas. Dose reductions of >10.0 Gy were observed with PBS compared to modern photon techniques for parotid glands, thyroid and pancreas. Following this technique, a wide range in dosimetry among centers using the same technique was observed (e.g., thyroid mean dose: VMAT: 5.6-24.6 Gy; PBS: 0.3-10.1 Gy). Conclusions: The investigated modern radiotherapy techniques demonstrate superior dosimetric results compared to 3D-CRT. The lowest mean dose for organs at risk is obtained with proton therapy. However, for a large number of organs ranges in mean doses were wide and overlapping between techniques making it difficult to recommend one radiotherapy technique over another. ARTICLE HISTORY

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Section: Discussionmentioning

confidence: 99%

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group)

et al. 2018

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“…Given the same setup errors, a larger gradient length reduced the associated dose deviations . Even though in the gradient method there is some anatomical limitation to the upper junction length, potential dose deviations in the upper and lower junctions were small after kilovoltage alignment …”

Section: Discussionmentioning

confidence: 99%

“…It has recently been shown that the most robust field‐junction to setup errors is obtained by the so‐called gradient‐optimized methods, i.e. by producing a slow, linear and complementary dose gradient at the beam edges in the overlapping region between adjacent beams . These methods showed a reduced sensitivity to longitudinal setup errors compared to the conventional feathering methods .…”

Section: Introductionmentioning

confidence: 99%

Universal field matching in craniospinal irradiation by a background‐dose gradient‐optimized method

Traneus

Bizzocchi²,

Fellin³

et al. 2017

J Applied Clin Med Phys

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PurposeThe gradient‐optimized methods are overcoming the traditional feathering methods to plan field junctions in craniospinal irradiation. In this note, a new gradient‐optimized technique, based on the use of a background dose, is described.MethodsTreatment planning was performed by RayStation (RaySearch Laboratories, Stockholm, Sweden) on the CT scans of a pediatric patient. Both proton (by pencil beam scanning) and photon (by volumetric modulated arc therapy) treatments were planned with three isocenters. An ‘in silico’ ideal background dose was created first to cover the upper‐spinal target and to produce a perfect dose gradient along the upper and lower junction regions. Using it as background, the cranial and the lower‐spinal beams were planned by inverse optimization to obtain dose coverage of their relevant targets and of the junction volumes. Finally, the upper‐spinal beam was inversely planned after removal of the background dose and with the previously optimized beams switched on.ResultsIn both proton and photon plans, the optimized cranial and the lower‐spinal beams produced a perfect linear gradient in the junction regions, complementary to that produced by the optimized upper‐spinal beam. The final dose distributions showed a homogeneous coverage of the targets.DiscussionOur simple technique allowed to obtain high‐quality gradients in the junction region. Such technique universally works for photons as well as protons and could be applicable to the TPSs that allow to manage a background dose.

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“…For pediatric patients who require anesthesia, many proton facilities generally allot a fixed time slot of 30–90 min for a treatment session depending upon the patient characteristics. Farace et al demonstrated that the average total in‐room time for craniospinal irradiation (CSI) pediatric patients was 80 min, under anesthesia, and 67 min without anesthesia, which included 32 min for beam delivery. Therefore, for efficient treatment‐room operation, it is important to complete the treatment within 30 min, irrespective of beam delivery with or without gating.…”

Section: Introductionmentioning

confidence: 99%

“…13 For pediatric patients who require anesthesia, many proton facilities generally allot a fixed time slot of 30-90 min for a treatment session depending upon the patient characteristics. Farace et al 14 15 However, to the best of our knowledge, the treatment process time for synchrotron-based gated proton-beam therapy has not been analyzed. The results of our study would be beneficial for many proton therapy facilities planning to introduce marker-based gated proton-beam therapy.…”

Section: Introductionmentioning

confidence: 99%

Analysis of treatment process time for real‐time‐image gated‐spot‐scanning proton‐beam therapy (RGPT) system

Yoshimura

Shimizu

Hashimoto

et al. 2019

J Applied Clin Med Phys

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We developed a synchrotron‐based real‐time‐image gated‐spot‐scanning proton‐beam therapy (RGPT) system and utilized it to clinically operate on moving tumors in the liver, pancreas, lung, and prostate. When the spot‐scanning technique is linked to gating, the beam delivery time with gating can increase, compared to that without gating. We aim to clarify whether the total treatment process can be performed within approximately 30 min (the general time per session in several proton therapy facilities), even for gated‐spot‐scanning proton‐beam delivery with implanted fiducial markers. Data from 152 patients, corresponding to 201 treatment plans and 3577 sessions executed from October 2016 to June 2018, were included in this study. To estimate the treatment process time, we utilized data from proton beam delivery logs during the treatment for each patient. We retrieved data, such as the disease site, total target volume, field size at the isocenter, and the number of layers and spots for each field, from the treatment plans. We quantitatively analyzed the treatment process, which includes the patient load (or setup), bone matching, marker matching, beam delivery, patient unload, and equipment setup, using the data obtained from the log data. Among all the cases, 90 patients used the RGPT system (liver: n = 34; pancreas: n = 5; lung: n = 4; and prostate: n = 47). The mean and standard deviation (SD) of the total treatment process time for the RGPT system was 30.3 ± 7.4 min, while it was 25.9 ± 7.5 min for those without gating treatment, excluding craniospinal irradiation (CSI; head and neck: n = 16, pediatric: n = 31, others: n = 15); for CSI (n = 11) with two or three isocenters, the process time was 59.9 ± 13.9 min. Our results demonstrate that spot‐scanning proton therapy with a gating function can be achieved in approximately 30‐min time slots.

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Supine craniospinal irradiation in pediatric patients by proton pencil beam scanning

Cited by 38 publications

References 28 publications

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group)

Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group)

Universal field matching in craniospinal irradiation by a background‐dose gradient‐optimized method

Analysis of treatment process time for real‐time‐image gated‐spot‐scanning proton‐beam therapy (RGPT) system

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