Proton therapy in clinical practice

Liu, Hui; Chang, Joe Y.

doi:10.5732/cjc.010.10529

Cited by 72 publications

(52 citation statements)

References 58 publications

(80 reference statements)

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“…PBS of proton beams allows for highly conformal treatment deliveries, minimizing dose to surrounding tissue (Saini et al, 2017, Liu andChang, 2011). This is accomplished by careful placement of spots tightly around the target volume in a way that limits dose to healthy tissue (Liu and Chang, 2011). However, other proton beam delivery techniques, such as passive scattering, employ aperture collimation that allows for sharper lateral penumbra than PBS without apertures.…”

Section: Introductionmentioning

confidence: 99%

Parametric characterization of penumbra reduction for aperture-collimated pencil beam scanning (PBS) proton therapy

Maes¹,

Regmi²,

Taddei³

et al. 2019

Biomed. Phys. Eng. Express

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Recently, a commercial treatment planning system (TPS) has implemented aperture collimators for PBS dose calculations which can serve to reduce lateral penumbra. This study characterized the variation in magnitude of lateral penumbra for collimated and un-collimated PBS fields versus the parameters of air gap, depth, and range shifter thickness. Comparisons were performed in a homogenous geometry between measured data and calculations made by a commercial TPS. Beam-specific target volumes were generated for collimated and un-collimated PBS fields and optimized for various range shifter thicknesses and air gaps. Lateral penumbra (80%-20% distance) was measured across each target volume to characterize penumbra variation with depth and air gap. An analytic equation was introduced to predict the reduction in lateral penumbra between un-collimated and collimated PBS treatments. Calculated penumbra values increased with depth across all combinations of range shifters for a constant air gap. At 2 cm depth, the reductions in penumbra due to the aperture were 2.7 mm, 3.7 mm and 4.2 mm when using range shifter thicknesses of 0 cm, 4.0 cm and 7.5 cm, respectively. At a depth of approximately 20 cm and air gap of 5 cm, differences between penumbras of collimated and un-collimated beams were less than 1 mm. Penumbra reductions for the collimated beams were largest at small air gaps. All TPScalculated penumbra values derived in this study were within 1 mm of film measurement values. Finally, the analytic equation was tested using a clinical CT scan, and we found good dosimetric agreement between the model predictions and the result calculated by the TPS. In conclusion, application of collimators to PBS fields can sharpen penumbra by several mm and are most beneficial for shallow targets. Furthermore, measurements indicate that the dose calculation accuracy in the penumbra region of PBS-collimated fields is adequate for clinical use. AbstractRecently, a commercial treatment planning system (TPS) has implemented aperture collimators for PBS dose calculations which can serve to reduce lateral penumbra. This study characterized the variation in magnitude of lateral penumbra for collimated and uncollimated PBS fields versus the parameters of air gap, depth, and range shifter thickness. Comparisons were performed in a homogenous geometry between measured data and calculations made by a commercial TPS. Beam-specific target volumes were generated for collimated and un-collimated PBS fields and optimized for various range shifter thicknesses and air gaps. Lateral penumbra (80%-20% distance) was measured across each target volume to characterize penumbra variation with depth and air gap. An analytic equation was introduced to predict the reduction in lateral penumbra between uncollimated and collimated PBS treatments. Calculated penumbra values increased with depth across all combinations of range shifters for a constant air gap. At 2 cm depth, the reductions in penumbra due to the aperture were 2.7 mm, 3.7 mm and 4.2 mm when using ran...

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Section: Introductionmentioning

confidence: 99%

Parametric characterization of penumbra reduction for aperture-collimated pencil beam scanning (PBS) proton therapy

Maes¹,

Regmi²,

Taddei³

et al. 2019

Biomed. Phys. Eng. Express

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“…Bu uygulamalar arasında glioblastoma, hipofiz adenomları, serebral arteriyo-venöz anevrizmalar, kafa tabanı sarkomları ve uveal melanomlar bulunmaktadır. [5] Hastane temelli proton tedavisi 1990'da Loma Linda Üniversite-sinde başlamış ve 2008 yılı sonuna kadar yaklaşık 13 bin hasta tedavi edilmiştir. [6] 2001'de MGH'de, 2006'da MD Anderson kanser merkezinde proton tedavi merkezleri faaliyete geçmiştir.1980'lerden 2000'li yıllara kadar araştırma enstitüleri içinde veya hastane temelli olmak üzere geniş bir yelpazede büyük bir çoğrafik bölgede proton tedavisi yayılmıştır.…”

Section: Tarihiunclassified

Role of proton therapy in the treatment of cancer

Hiçsönmez

2013

TJ Oncol

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“…Recently, studies focused on predicting patient‐specific dosimetric benefits of PT and dose escalation. For example, Liu et al . demonstrated that proton radiation dose escalation improved local control but also increased toxicity.…”

Section: Introductionmentioning

confidence: 99%

“…5 Recently, studies focused on predicting patient-specific dosimetric benefits of PT 6 and dose escalation. For example, Liu et al 7 demonstrated that proton radiation dose escalation improved local control but also increased toxicity. However, the lack of identifying biomarkers for conclusive patient outcome, limits the transfer of PT into personalized medicine.…”

Section: Introductionmentioning

confidence: 99%

Dosimetry and characterization of a 25‐MeV proton beam line for preclinical radiobiology research

et al. 2019

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Purpose With the increase in proton therapy centers, there is a growing need to make progress in preclinical proton radiation biology to give accessible data to medical physicists and practicing radiation oncologists. Methods A cyclotron usually producing radioisotopes with a proton beam at an energy of about 25 MeV after acceleration, was used for radiobiology studies. Depleted silicon surface barrier detectors were used for the beam energy measurement. A complementary metal oxide semiconductor (CMOS) sensor and a plastic scintillator detector were used for fluence measurement, and compared to Geant4 and an in‐house analytical dose modeling developed for this purpose. Also, from the energy measurement of each attenuated beam, the dose‐averaged linear energy transfer (LETd) was calculated with Geant4. Results The measured proton beam energy was 24.85 ± 0.14 MeV with an energy straggling of 127 ± 22 keV before scattering and extraction in air. The measured flatness was within ± 2.1% over 9 mm in diameter. A wide range of LETd is achievable: constant between the entrance and the exit of the cancer cell sample ranging from 2.2 to 8 keV/μm, beyond 20 keV/μm, and an average of 2–5 keV/μm in a scattering spread‐out Bragg peak calculated for an example of a 6‐mm‐thick xenograft tumor. Conclusion The dosimetry and the characterization of a 25‐MeV proton beam line for preclinical radiobiology research was performed by measurements and modeling, demonstrating the feasibility of delivering a proton beam for preclinical in vivo and in vitro studies with LETd of clinical interest.

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Proton therapy in clinical practice

Cited by 72 publications

References 58 publications

Parametric characterization of penumbra reduction for aperture-collimated pencil beam scanning (PBS) proton therapy

Parametric characterization of penumbra reduction for aperture-collimated pencil beam scanning (PBS) proton therapy

Role of proton therapy in the treatment of cancer

Dosimetry and characterization of a 25‐MeV proton beam line for preclinical radiobiology research

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