Peta's project assesses the radiation exposure of normal healthy tissue which inevitably arises during radiotherapy for breast cancer. In Australia, 16,000 women are diagnosed with breast cancer every year. Approximately half of those diagnosed would benefit from at least one course of radiotherapy as part of their overall treatment, translating to a large number of women exposed to radiation. Treatment-related side effects are therefore an important consideration for a large number of patients. With modern treatment options offering breast cancer patients favourable long-term outcomes, treatment-related toxicities are becoming an increasingly important factor in quality of life after cancer treatment. This work examined how both technology and patient related factors affect the additional radiation exposure to untargeted healthy tissue, provides improved methods of estimating out-of-field dose, and provides recommendations for reducing this additional radiation exposure.

 Significance & other outcomes:

As a result of this project, a specialised high-sensitivity radiation detector has been implemented for routine patient measurements at the Peter MacCallum Cancer Centre, which treats approximately 7,000 patients annually across its 5 campuses in Victoria. These small, detectors can be placed on patients' skin during radiation treatment and are used to verify doses to the treated area as well as assess low doses to normal healthy tissue located away from the radiation beams. This has allowed several low-dose assessments under various clinical scenarios with examples including dose to the lens of eyes, and foetal doses in pregnant patients.

Summary of outputs

5 first-author publications & 15 conference presentations (listed below).

First author publications:

1.  Lonski P, Keehan S, Siva S, Pham D, Franich R, Taylor M, et al. Out-of-field in vivo dosimetry using TLD in SABR for primary kidney cancer involving mixed photon fields. Physica Medica. 2017;37:9-15.

2.  Lonski P, Kron T, Taylor M, Phipps A, Franich R, Chua B. Assessment of leakage dose in vivo in patients undergoing radiotherapy for breast cancer. Physics and Imaging in Radiation Oncology. 2018;5:97-101.

3.  Lonski P, Ramachandran P, Franich R, Kron T. Surface dose measurements in and out of field: Implications for breast radiotherapy with megavoltage photon beams. Zeitschrift für Medizinische Physik. 2017.

4.  Lonski P, Taylor ML, Franich RD, Kron T. A collimated detection system for assessing leakage dose from medical linear accelerators at the patient plane. Australas Phys Eng Sci Med. 2014;37(1):15-23.

5.  Lonski P, Taylor ML, Franich RD, Harty P, Kron T. Assessment of leakage doses around the treatment heads of different linear accelerators. Radiat Prot Dosimetry. 2012;152(4):304-12.

Conference presentations:

•P Lonski*, R Antony, L Marsh and T Kron, “Impact of in vivo dosimetry in a large radiotherapy department”, Engineering and Physical Scientists in Medicine (EPSM) 2017, Hobart, Tasmania

•P Lonski*, RD Franich, R Prabhakar and T Kron, “Assessment of surface dose from a TrueBeam linear accelerator for breast radioatherapy”, EPSM 2016, Sydney, Australia

•P Lonski*, RD Franich, R Prabhakar and T Kron, “Surface dose measurements in FFF beams using a thin window chamber”, ICMP 2016, Bangkok, Thailand

•P Lonski*, D Jolly, B Chua, D Philips, M Portillo, S David, A Philips and T Kron, “Change in Hounsfield Units due to lung expansion as a predictor of LAD and heart displacement in patients undergoing deep inspiration breath hold for left sided breast cancer” IUPESM World Congress Meeting, 2015, Toronto, Canada

•P Lonski*, D Jolly, S Siva, D Ball, B Chua, D Philips, M Portillo, S David, A Philips and T Kron, “Assessment of lung dose in patients undergoing deep inspiration breath hold for left sided breast cancer”, IUPESM World Congress Meeting, 2015, Toronto, Canada

•P Lonski*, RD Franich, W Hackworth, S Keehan, ML Taylor and T Kron, “Out-of-field radiation dose during radiotherapy for breast cancer: improvement of dose estimation by addition of a correction for leakage dose” ARPS conference 2014, Hobart, Tasmania

•P Lonski*, RD Franich, S Keehan, ML Taylor, D Pham, S Siva and T Kron, “Out-of-field in vivo dosimetry in patients undergoing stereotactic ablative body radiotherapy for primary kidney cancer”, 2014 Combined Scientific Meeting, Melbourne Australia

•P Lonski*, R. Franich, M. Taylor, W. Hackworth, T. Kron, ”Shielding effects of the primary collimator: Assessment of the accuracy of treatment planning system dose calculations out-of-field” 2014 Combined Scientific Meeting, Melbourne Australia

•P Lonski*, RD Franich, S Siva, S Keehan, ML Taylor and T Kron, “In vivo neutron detection in patients undergoing SABR for primary kidney cancer using 6Li and 7Li enriched TLD pairs”, AAPM, Austin, Texas, USA, 2014

•P Lonski*, ML Taylor, Alicia Phipps, RD Franich and T Kron, “In vivo verification of treatment planning system dose calculations at out-of-field locations”, ICCR, Melbourne, 2013

•P Lonski*, RD Franich, S Siva, ML Taylor and T Kron, “In-vivo detection of neutrons produced during high-energy radiotherapy using Li-6 and Li-7 enriched TLD pairs EPSM”, November 2013, Perth, Australia

•T Kron, P. Lonski*, C.J. Hornby, E. Muir, J. Hagekyriakou and A. Wirth, “Mediastinal radiotherapy for lymphoma: breast dose reduction by breast repositioning”, EPSM, November 2013, Perth, Australia

•P Lonski*, ML Taylor, A Phipps, RD Franich, B Chua and T Kron, “In vivo verification of radiation dose delivered to healthy tissue during tangential beam radiotherapy for breast cancer”, EPSM, Gold Coast, Queensland Australia, December 2012

•P Lonski*, ML Taylor RD Franich, and T Kron, “A focused measurement system for analysing leakage dose from medical linear accelerators”, EPSM, Gold Coast, Queensland Australia, December 2012

•P Lonski, ML Taylor, RD Franich, P Harty, N Clements and T Kron*, “Leakage patterns of linear accelerator treatment heads from multiple vendors”, conference abstract EPSM conference, Darwin, August 14 -18, 2011