PhD Offer: Evaluation of the Clinical and Dosimetric Benefits of Non-Invasive Ventilation for Lung SBRT.

Position:

Institution: Centre Léon Bérard, Lyon, France

Location:

Application closes at: Jun 14th, 2025 20:00

Scientific Context: One of the challenges in thoracic radiotherapy is the tumor motion induced by the patient breathing all along the treatment delivery. Tumors located in the inferior lobes are more subjected to large amplitudes, up to 4cm (1). Consequently, a larger target volume has to be considered, namely the Internal Target Volume (ITV), at the cost of a larger proportion of healthy tissue irradiated.

For lung stereotactic treatments (SBRT), performed in free-breathing, and delivering 10 to 30Gy per fraction, the 4-dimensional computed tomography (4D-CT) remains the standard imaging as it depicts the patient-specific motion (2). Due to patient irregular breathing (amplitude variation) and longer breathing period, artifacts can occur in the 4D-CT images, detrimentally impacting the tumor volume accuracy (3).

Several motion management strategies were developed to compensate for the tumor movement (4): passive techniques (ITV, Mid-P and Mid-V strategies) and active techniques (Gating, Tracking and Breath-hold). Several authors recently demonstrated the safety and feasibility of using Non-Invasive Mechanical Ventilation in radiotherapy as an alternative solution for motion management (5,6). NIMV consists in using a mechanical ventilator to constrain the patient’s respiratory (in rate and volume), inducing regular and reproducible breathing (volume-controlled mode). With appropriate parameters, NIMV can also reduce the breathing amplitude or induce repeated end-inspiration breath-hold of a few seconds or even minutes.

In our institution, patients receiving lung SBRT are currently treated either with the ITV strategy on a conventional Linac, or with the tracking strategy on the Cyberknife. To reduce artifacts in 4D-CT scans (Tracking - Cyberknife) or freeze tumor motion (Breath-Hold - conventional Linac), NIMV will be implemented in the next few months.

In this context, the goal of this PhD project will be to:

1/ Assess the artifacts reduction in 4D-CT images using NIMV (for free-breathing treatment)

2/ Quantify the intra-fraction shifts using CBCT for Breath-hold treatment

3/ Assess the dosimetric and clinical benefits using NIMV (volume-controlled mode/ breath-hold mode)

4/ Establish a decision-tree for tailored lung SBRT integrating the different strategies available in our institution (ITV/Tracking/Breath-Hold).

The PhD will be conducted in the CREATIS lab, team “tomoradio”, located in the radiation therapy department of the Léon Bérard cancer center, Lyon, France.

The PhD student will work in close collaboration with the clinicians of the CLB and searchers from the CREATIS laboratory.  A clinical partnership is also underway between the Centre Léon Bérard and the University of Louvain, involving Dr. Geneviève Van Ooteghem.

References:

(1) Seppenwoolde Y, Shirato H, Kitamura K, et al. Precise and real-time measurement of 3D tumor motion in lung due to breathing and heartbeat, measured during radiotherapy. Int J Radiat Oncol Biol Phys 2002;53:822-34. DOI: 10.1016/s0360-3016(02)02803-1

(2) Guckenberger M, Andratschke N, Dieckmann K, Hoogeman MS, Hoyer M, Hurkmans C, Tanadini-Lang S, Lartigau E, Méndez Romero A, Senan S, Verellen D. ESTRO ACROP consensus guideline on implementation and practice of stereotactic body radiotherapy for peripherally located early stage non-small cell lung cancer. Radiother Oncol. 2017 Jul;124(1):11-17. doi: 10.1016/j.radonc.2017.05.012.

(3) Yamamoto T, Langner U, Loo BW Jr, Shen J, Keall PJ. Retrospective analysis of artifacts in four-dimensional CT images of 50 abdominal and thoracic radiotherapy patients. Int J Radiat Oncol Biol Phys. 2008 Nov 15;72(4):1250-8. doi: 10.1016/j.ijrobp.2008.06.1937.

(4) Keall PJ, Mageras GS, Balter JM, Emery RS, Forster KM, Jiang SB, Kapatoes JM, Low DA, Murphy MJ, Murray BR, Ramsey CR, Van Herk MB, Vedam SS, Wong JW, Yorke E. The management of respiratory motion in radiation oncology report of AAPM Task Group 76. Med Phys. 2006 Oct;33(10):3874-900. doi: 10.1118/1.2349696.

(5) Van Ooteghem G, Dasnoy-Sumell D, Lee JA, Geets X. Mechanically-assisted and non-invasive ventilation for radiation therapy: A safe technique to regularize and modulate internal tumour motion. Radiother Oncol. 2019 Dec;141:283-291. doi: 10.1016/j.radonc.2019.09.021.

(6) Nicholas S West, Michael J Parkes, Christopher Snowden, James Prentis, Jill McKenna, Muhammad Shahid Iqbal, Jason Cashmore, Christopher Walker. Mitigating Respiratory Motion in Radiation Therapy: Rapid, Shallow, Non-invasive Mechanical Ventilation for Internal Thoracic Targets. Int J Radiat Oncol Biol Phys. 2019 Mar 15;103(4):1004-1010. doi: 10.1016/j.ijrobp.2018.11.040.

 

Applicant profile: Medical physicist, data analysis

Location: Léon Bérard center, Medical Physics unit, Radiotherapy department, CREATIS lab, Lyon, France

Length: 3 years starting in September 2025

Contact: Please send your CV and application letter by email to:

- Myriam Ayadi-Zahra, medical physicist PhD, Medical Physics unit, Radiotherapy department, Leon Bérard Center, Lyon, myriam.ayadi@lyon.unicancer.fr

- Marie-Claude Biston, Head of the Medical Physics unit, HDR, Radiotherapy department, Leon Bérard Center, Lyon, &CREATIS laboratory, Lyon, marie-claude.biston@lyon.unicancer.fr

- Dr Isabelle Martel-Lafay, Radiation-Oncologist, Radiotherapy department, Leon Bérard Center, Lyon, isabelle.martel-lafay@lyon.unicancer.fr

Applications will be gathered until end of May 2025. Interviews will be conducted by videoconference or in Lyon depending on availability.