1406 ORAL Parotid gland sparing in paediatric patients receiving radiotherapy for infratentorial tumours: Optimization of treatment technique to improve normal tissue sparing

AbstractPurpose:To compare the dosimetric results regarding the sparing effect on normal tissue between RapidArc (RA) and helical tomotherapy (HT) plans for nasopharyngeal carcinoma (NPC) patients in cases of the equal target dose controls utilising two techniques.Materials and Methods:Thirteen NPC patients treated with HT were replanned using the Varian Eclipse treatment planning system (TPS) for the RA plan. The target dose of the RA plan was optimised equally to the HT plan in terms of target coverage, dose conformity (CI) and dose homogeneity (HI) for assessing the normal tissue sparing between two techniques. All dose–volume parameters monitor units (MUs) and delivery time were also investigated.Results:All dosimetric parameter comparisons of organs-at-risk (OARs) between the RA and HT plans were not significantly different for brain stem, spinal cord and cochlea. However, the RA plan showed a significantly lower dose to the left parotid gland. The mean and median dose were significantly lower in the RA plan versus the HT plan by p-value 0·005 and 0·039, respectively. The MUs and delivery time were also significantly lower in the RA plan with a p-value of 0·00.Conclusions:With the same planning target volume coverage, homogeneity and conformity, almost all of RA and HT treatment planning met the planning goal for normal tissue sparing. There were no significant differences between the two techniques except in the left parotid gland. The RA plans were superior to HT plans by effectively reducing the MUs and treatment time.

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Normal tissue sparing potential of scanned proton beams with and without respiratory gating for the treatment of internal mammary nodes in breast cancer radiotherapy

Physica Medica ◽

10.1016/j.ejmp.2018.06.639 ◽

2018 ◽

Vol 52 ◽

pp. 81-85 ◽

Cited By ~ 3

Author(s):

Alexandru Dasu ◽

Anna M. Flejmer ◽

Anneli Edvardsson ◽

Petra Witt Nyström

Keyword(s):

Breast Cancer ◽

Normal Tissue ◽

Respiratory Gating ◽

Cancer Radiotherapy ◽

Proton Beams ◽

Normal Tissue Sparing ◽

Internal Mammary Nodes ◽

Breast Cancer Radiotherapy ◽

Internal Mammary ◽

Tissue Sparing

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The normal tissue sparing obtained with simultaneous treatment of pelvic lymph nodes and bladder using intensity-modulated radiotherapy

Acta Oncologica ◽

10.1080/02841860802251575 ◽

2009 ◽

Vol 48 (2) ◽

pp. 238-244 ◽

Cited By ~ 33

Author(s):

Jimmi Søndergaard ◽

Morten Høyer ◽

Jørgen B. Petersen ◽

Pauliina Wright ◽

Cai Grau ◽

...

Keyword(s):

Lymph Nodes ◽

Normal Tissue ◽

Intensity Modulated Radiotherapy ◽

Simultaneous Treatment ◽

Pelvic Lymph Nodes ◽

Intensity Modulated ◽

Normal Tissue Sparing ◽

Tissue Sparing

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Normal tissue sparing using different techniques for prostate irradiation

Reports of Practical Oncology & Radiotherapy ◽

10.1016/j.rpor.2019.11.001 ◽

2020 ◽

Vol 25 (1) ◽

pp. 85-90

Author(s):

Barbara Melles-Bencsik ◽

Tamás Pócza ◽

Tibor Major ◽

Péter Ágoston ◽

Kliton Jorgo ◽

...

Keyword(s):

Normal Tissue ◽

Normal Tissue Sparing ◽

Tissue Sparing

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Influence of Target Location, Size, and Patient Age on Normal Tissue Sparing- Proton and Photon Therapy in Paediatric Brain Tumour Patient-Specific Approach

Cancers ◽

10.3390/cancers12092578 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2578

Author(s):

Mikaela Dell’Oro ◽

Michala Short ◽

Puthenparampil Wilson ◽

Chia-Ho Hua ◽

Melissa Gargone ◽

...

Keyword(s):

Normal Tissue ◽

Optic Chiasm ◽

Patient Specific ◽

Patient Age ◽

Dose Distributions ◽

Intensity Modulated ◽

Normal Tissue Sparing ◽

Patient Âgé ◽

Tissue Sparing ◽

Photon Radiotherapy

Background: Proton radiotherapy produces superior dose distributions compared to photon radiotherapy, reducing side effects. Differences between the two modalities are not fully quantified in paediatric patients for various intracranial tumour sites or age. Understanding these differences may help clinicians estimate the benefit and improve referral across available centres. Our aim was to compare intensity-modulated proton therapy (IMPT) and intensity-modulated photon radiotherapy (IMRT) radiation doses for select paediatric intracranial tumours. Methods: IMPT and IMRT dose distributions for gender-matched paediatric cranial CT-datasets (ages 5, 9 and 13 years) were retrospectively calculated to simulate irradiation of supratentorial (ependymoma) and infratentorial (medulloblastoma) target volumes diameters (1–3 cm) and position (central and 1–2 cm shifts). Results: Clinical dosimetric objectives were achieved for all 216 treatment plans. Whilst infratentorial IMPT plans achieved greater maximum dose sparing to optic structures (4.8–12.6 Gy optic chiasm), brainstem sparing was limited (~0.5 Gy). Mean dose difference for optic chiasm was associated with medulloblastoma target position (p < 0.0197). Supratentorial IMPT plans demonstrated greater dose reduction for the youngest patients (pituitary gland p < 0.001). Conclusions: Normal tissue sparing was achieved regardless of patient age for infratentorial tumours. However, for supratentorial tumours, there was a dosimetric advantage of IMPT across 9 vs. 13-year-old patients.

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