Clinical Characterization of a Table Mounted Range Shifter Board for Synchrotron-Based Intensity Modulated Proton Therapy for Pediatric Craniospinal Irradiation

Overview

Journal Cancers (Basel)

Publisher MDPI

Specialty Oncology

Date 2023 Jun 10

PMID 37296845

Authors

William T Hrinivich

Heng Li

Anh Tran

Sahaja Acharya

Matthew M Ladra

Khadija Sheikh

Affiliations

Soon will be listed here.

Abstract

: To report our design, manufacturing, commissioning and initial clinical experience with a table-mounted range shifter board (RSB) intended to replace the machine-mounted range shifter (MRS) in a synchrotron-based pencil beam scanning (PBS) system to reduce penumbra and normal tissue dose for image-guided pediatric craniospinal irradiation (CSI). : A custom RSB was designed and manufactured from a 3.5 cm thick slab of polymethyl methacrylate (PMMA) to be placed directly under patients, on top of our existing couch top. The relative linear stopping power (RLSP) of the RSB was measured using a multi-layer ionization chamber, and output constancy was measured using an ion chamber. End-to-end tests were performed using the MRS and RSB approaches using an anthropomorphic phantom and radiochromic film measurements. Cone beam CT (CBCT) and 2D planar kV X-ray image quality were compared with and without the RSB present using image quality phantoms. CSI plans were produced using MRS and RSB approaches for two retrospective pediatric patients, and the resultant normal tissue doses were compared. : The RLSP of the RSB was found to be 1.163 and provided computed penumbra of 6.9 mm in the phantom compared to 11.8 mm using the MRS. Phantom measurements using the RSB demonstrated errors in output constancy, range, and penumbra of 0.3%, -0.8%, and 0.6 mm, respectively. The RSB reduced mean kidney and lung dose compared to the MRS by 57.7% and 46.3%, respectively. The RSB decreased mean CBCT image intensities by 86.8 HU but did not significantly impact CBCT or kV spatial resolution providing acceptable image quality for patient setup. : A custom RSB for pediatric proton CSI was designed, manufactured, modeled in our TPS, and found to significantly reduce lateral proton beam penumbra compared to a standard MRS while maintaining CBCT and kV image-quality and is in routine use at our center.

References

Lin H, Ding X, Kirk M, Liu H, Zhai H, Hill-Kayser C . Supine craniospinal irradiation using a proton pencil beam scanning technique without match line changes for field junctions. Int J Radiat Oncol Biol Phys. 2014; 90(1):71-8. DOI: 10.1016/j.ijrobp.2014.05.029. View

Seravalli E, Bosman M, Lassen-Ramshad Y, Vestergaard A, Oldenburger F, Visser J . Dosimetric comparison of five different techniques for craniospinal irradiation across 15 European centers: analysis on behalf of the SIOP-E-BTG (radiotherapy working group). Acta Oncol. 2018; 57(9):1240-1249. DOI: 10.1080/0284186X.2018.1465588. View

Stoker J, Grant J, Zhu X, Pidikiti R, Mahajan A, Grosshans D . Intensity modulated proton therapy for craniospinal irradiation: organ-at-risk exposure and a low-gradient junctioning technique. Int J Radiat Oncol Biol Phys. 2014; 90(3):637-44. DOI: 10.1016/j.ijrobp.2014.07.003. View

Winterhalter C, Lomax A, Oxley D, Weber D, Safai S . A study of lateral fall-off (penumbra) optimisation for pencil beam scanning (PBS) proton therapy. Phys Med Biol. 2018; 63(2):025022. DOI: 10.1088/1361-6560/aaa2ad. View

Kirby D, Green S, Palmans H, Hugtenburg R, Wojnecki C, Parker D . LET dependence of GafChromic films and an ion chamber in low-energy proton dosimetry. Phys Med Biol. 2009; 55(2):417-33. DOI: 10.1088/0031-9155/55/2/006. View

Yuh G, Loredo L, Yonemoto L, Bush D, Shahnazi K, Preston W . Reducing toxicity from craniospinal irradiation: using proton beams to treat medulloblastoma in young children. Cancer J. 2005; 10(6):386-90. DOI: 10.1097/00130404-200411000-00009. View

Farace P, Bizzocchi N, Righetto R, Fellin F, Fracchiolla F, Lorentini S . Supine craniospinal irradiation in pediatric patients by proton pencil beam scanning. Radiother Oncol. 2017; 123(1):112-118. DOI: 10.1016/j.radonc.2017.02.008. View

Safai S, Bortfeld T, Engelsman M . Comparison between the lateral penumbra of a collimated double-scattered beam and uncollimated scanning beam in proton radiotherapy. Phys Med Biol. 2008; 53(6):1729-50. DOI: 10.1088/0031-9155/53/6/016. View

Shen J, Liu W, Anand A, Stoker J, Ding X, Fatyga M . Impact of range shifter material on proton pencil beam spot characteristics. Med Phys. 2015; 42(3):1335-40. PMC: 5148134. DOI: 10.1118/1.4908208. View

10.

Yoon M, Shin D, Kim J, Kim J, Kim D, Park S . Craniospinal irradiation techniques: a dosimetric comparison of proton beams with standard and advanced photon radiotherapy. Int J Radiat Oncol Biol Phys. 2010; 81(3):637-46. DOI: 10.1016/j.ijrobp.2010.06.039. View

11.

Bernier V, Klein O . Late effects of craniospinal irradiation for medulloblastomas in paediatric patients. Neurochirurgie. 2018; 67(1):83-86. DOI: 10.1016/j.neuchi.2018.01.006. View

12.

Kang M, Hasan S, Press R, Yu F, Abdo M, Xiong W . Using patient-specific bolus for pencil beam scanning proton treatment of periorbital disease. J Appl Clin Med Phys. 2020; 22(1):203-209. PMC: 7856513. DOI: 10.1002/acm2.13134. View

13.

Arjomandy B, Taylor P, Ainsley C, Safai S, Sahoo N, Pankuch M . AAPM task group 224: Comprehensive proton therapy machine quality assurance. Med Phys. 2019; 46(8):e678-e705. DOI: 10.1002/mp.13622. View

14.

Lin H, Shi C, Huang S, Shen J, Kang M, Chen Q . Applications of various range shifters for proton pencil beam scanning radiotherapy. Radiat Oncol. 2021; 16(1):146. PMC: 8344212. DOI: 10.1186/s13014-021-01873-8. View

15.

Miralbell R, Lomax A, Cella L, Schneider U . Potential reduction of the incidence of radiation-induced second cancers by using proton beams in the treatment of pediatric tumors. Int J Radiat Oncol Biol Phys. 2002; 54(3):824-9. DOI: 10.1016/s0360-3016(02)02982-6. View

16.

Newhauser W, Fontenot J, Mahajan A, Kornguth D, Stovall M, Zheng Y . The risk of developing a second cancer after receiving craniospinal proton irradiation. Phys Med Biol. 2009; 54(8):2277-91. PMC: 4144016. DOI: 10.1088/0031-9155/54/8/002. View

17.

Sorriaux J, Testa M, Paganetti H, de Xivry J, Lee J, Traneus E . Experimental assessment of proton dose calculation accuracy in inhomogeneous media. Phys Med. 2017; 38:10-15. DOI: 10.1016/j.ejmp.2017.04.020. View

18.

Kern A, Baumer C, Kroninger K, Wulff J, Timmermann B . Impact of air gap, range shifter, and delivery technique on skin dose in proton therapy. Med Phys. 2020; 48(2):831-840. DOI: 10.1002/mp.14626. View

19.

Zhang R, Howell R, Taddei P, Giebeler A, Mahajan A, Newhauser W . A comparative study on the risks of radiogenic second cancers and cardiac mortality in a set of pediatric medulloblastoma patients treated with photon or proton craniospinal irradiation. Radiother Oncol. 2014; 113(1):84-8. PMC: 4256116. DOI: 10.1016/j.radonc.2014.07.003. View

20.

Gillin M, Sahoo N, Bues M, Ciangaru G, Sawakuchi G, Poenisch F . Commissioning of the discrete spot scanning proton beam delivery system at the University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston. Med Phys. 2010; 37(1):154-63. PMC: 11078095. DOI: 10.1118/1.3259742. View