This study deals with the characteristics of simultaneous photon and electron beams in homogenous and inhomogeneous phantoms by experimental and Monte Carlo dosimetry, for therapeutic purposes. Materials and methods: Both 16 and 20 MeV high-energy electron beams were used as the original beam to strike perforated lead sheets to produce the mixed beam. The dosimetry results were achieved by measurement in an ion chamber in a water phantom and film dosimetry in a Perspex nasal phantom, and then compared with those calculated through a simulation approach. To evaluate two-dimensional dose distribution in the inhomogeneous medium, the dose–area histogram was obtained.

The highest percentage of photon contribution in mixed beam was found to be 36% for 2-mm thickness of lead layer with holes diameter of 0·2 cm for a 20 MeV primary electron energy. For small fields, the percentage depth dose parameters variations were found to be similar to pure electron beam within ±2%. The most feasible flatness in beam profile was 11% for pure electron and 7% for the mixed beam. Penumbra changes as function of depth was about ten times better than in pure electron field.

The results present some dosimetric advantages that can make this study a platform for the production of simultaneous mixed beams in future linear accelerators (LINACs), which through redesign of the LINAC head, which could lead to setup error reduction and a decrease of intra-fractional tumour cells repair.

Treatment volumes for radical radiotherapy to head and neck cancers commonly extend into the lower neck, the territory of the brachial plexus (BP). There is a risk of radiation-induced brachial plexopathy, a non-reversible late toxicity experienced by a small number of patients. The BP was anatomically divided into superior and inferior divisions and analysed to establish if segmental inter-fractional BP movement should be considered when planning radiotherapy in this high-dose region.

A retrospective single-centre analysis of 15 patients with head and neck cancers treated with radical bilateral neck irradiation was conducted. The extent of BP movement relative to the planning scan was assessed using weekly cone beam computed tomography (CBCT) scans. The BP was contoured on the planning scan and the subsequent six weekly CBCTs; this was used to calculate the Jaccard Conformity Index (JCI) for the left, right, superior and inferior divisions of the BP.

The mean (±SD) JCI for right and left superior BP was 44·4±15·5%, whereas the mean (±SD) JCI for right and left inferior BP was 38·3±15·5%. There was a statistically significant difference between superior and inferior JCI, p=0·0002, 95% CI (−9·26 to −2·88). Bilateral superior BP JCI was higher, with better conformity than the corresponding inferior divisions.

Inter-fractional BP movement occurs; the greatest movement is seen at the inferior division. This data suggest the need for re-evaluation of current BP margins and consideration of a larger inferior BP planning at risk volume (PRV) margin.

To develop an auto-generated patient discharge summary for all patients being treated in the Radiation Therapy Department.

A patient discharge summary was developed using auto-generated data for all patients being treated in the Radiation Therapy Department. This ensures information relevant to the care of the patient is communicated effectively during transitions of care following radiation treatment, and provides a record of the treatment site(s), dose delivered, start/completion dates and contact information for Radiation Oncologists. The eScribe feature in MosaiQTM is utilised to auto-generate the patient discharge summary in less than one minute, and then printed and given to patients on the last day of treatment. This was piloted with palliative radiotherapy patients (n=22), who also completed a telephone survey.

Results revealed patients had passed this document onto other healthcare providers and appreciated having a record of their treatments. Feedback was obtained from radiation therapy staff and the Patient and Family Advisory Committee. Subsequently, the language of the patient discharge summary was simplified and a disclaimer was added, indicating the document is not a complete radiation therapy treatment record. This initiative was then rolled out to all radiotherapy patients.

Overall, the patient discharge summary allows for a quick, automated and standardised approach for transfer of information during care transitions without significant impact to the Radiation Therapy Departmental workflow.

Patient involvement in health profession student training is becoming more common and includes clinical case studies, informing curriculum development and active teaching in dedicated patient experience sessions. Despite a growing evidence base supporting patient involvement, there is little published data concerning motivation for involvement. A qualitative study was performed to provide narrative relating to patient experiences in expert patient sessions on an undergraduate radiation therapy course.

A phenomenological approach utilised semi-structured interviews with two expert patients from different backgrounds. A common set of questions were used for each participant. Interviews were digitally recorded and transcribed before thematic coding.

Both participants identified areas of similarity as well as key difference in their experiences. Both had different levels of public speaking experience as well as different levels of knowledge relating to radiation therapy treatment. Both found the initial session emotional but ultimately enjoyed the process and found it cathartic.

The patients enjoyed this experience and identified clear value of the teaching for themselves and the students. Previous public speaking or clinical experience seemed to have limited impact on patient experience and suggested the vulnerability of the situation. Both had different perspectives of their fellow patients and their role in the healthcare partnership. These findings indicate the value of ensuring students have access to a range of perspectives from different patients.

The aim of this study was to optimise patient dose and image quality of Varian TrueBeam cone beam computed tomography (CBCT) pelvis, thorax and head and neck (H&N) images based on patient size.

An elliptical phantom of small, medium and large size was designed representative of a local population of pelvis, thorax and H&N patients. The phantom was used to establish the relationship between image noise, CT and CBCT exposure settings. Using this insight, clinical images were optimised in phases and the image quality graded qualitatively by radiographers. At each phase, the time required to match the images was recorded from the record and verify system.

Average patient diameter was a suitable metric to categorise patient size. Phantom measurements showed the power relationship between noise and CBCT exposure settings of value −0·15, −0·35 and −0·43 for thorax, pelvis and H&N, respectively. These quantitative phantom measurements provided confidence that phased variation of ~±20% in mAs should result in clinically usable images. Qualitative assessment of almost 2000 images reduced the exposure settings in H&N images by −50%, thorax images by up to −66% and pelvis images by up to −80%. These optimised CBCT settings did not affect the time required to match images.

Varian TrueBeam CBCT mAs settings have been optimised for dose and image quality based on patient size for three treatment sites: pelvis, thorax and H&N. Quantitative phantom measurements provided insight into the magnitude of change to implement clinically. The final optimised exposure settings were determined from radiographer qualitative image assessment.

For patients with locally advanced laryngeal cancer, two main treatment options are either up-front surgery [total laryngectomy (TL)] followed by postoperative adjuvant radiation therapy (RT) or definitive concurrent chemoradiation (CCRT) with surgery retained as salvage. The objectives were to study the feasibility of CCRT using intensity-modulated radiation therapy (IMRT) in locally advanced laryngeal cancer with respect to response, toxicities, and quality of life (QoL) and comparison with other modality—TL with post-operative RT.

The records of 48 patients with locally advanced laryngeal cancer (T3/T4aN0-2), registered between years 2014 and 2017, treated with IMRT (definitive or adjuvant postoperative IMRT) were analysed from the hospital database. The patients received RT either as definitive CCRT or as adjuvant treatment after TL. RT in all patients was delivered with IMRT-SIB(simultaneous integrated boost) technique and concurrent chemotherapy with weekly cisplatin. The response was assessed at 12 weeks. Toxicities and QoL were assessed and compared between patients receiving definitive CCRT and adjuvant RT.

92·3% patients who received definitive CCRT achieved complete response. Toxicities were of low grade in patients receiving both definitive and adjuvant treatments. All the patients (except two partial responders of CCRT) remained disease-free at the last follow-up. At 2 years of follow-up of each patient—Global QoL, emotional and social functioning were better in definitive CCRT patients. Laryngectomy patients had more dyspnoea, insomnia and financial difficulties. Although the problems of dry mouth, sticky saliva and swallowing were comparable, laryngectomy patients faced more problems with speech, senses, social eating, social contact and cough.

Definitive CCRT using IMRT-SIB with weekly cisplatin is a feasible option for patients of locally advanced laryngeal cancer with acceptable response rate. IMRT yields better toxicity outcomes with sparing of organs at risk. CCRT patients have better QoL than laryngectomy patients in several parameters.

Varying the calculation grid size can change the results of dose-volume and radiobiological parameters in a treatment plan, and therefore has an impact on the treatment planning quality assurance.

This study investigated the dosimetric influence of the calculation grid size variation in the prostate volumetric modulated arc therapy (VMAT) plan.

Dose distributions of 10 prostate VMAT plans were acquired using calculation grid sizes of 1–5 mm. Dose-volume histogram (DVH) analysis was carried out to determine the dose-volume variation corresponding to the grid size change using the Gaussian error function (GEF). At the same time, dose-volume points, dose-volume parameters and radiobiological parameters were calculated based on DVHs of targets and organs at risk (OARs) for each grid size.

Comparing percentage variations of GEF parameters between the planning target volume (PTV) and clinical target volume (CTV), GEF parameters of the PTV were found varied more significantly than the CTV. This resulted in larger variations of dose-volume (%ΔCI=40·02 versus 13·55%, %ΔHI=12·45 versus 2·93% and %ΔGI=0·22 versus 0·06%) and radiobiological parameters (%ΔTCP=0·61 versus 0·25% and %ΔEUD=2·11 versus 0·26%) of the PTV compared with CTV. For OARs, the rectal wall showed a larger dose-volume variation than the rectum. However, similar dose-volume variation due to grid size change was not found in the bladder, bladder wall and femur.

Knowing the dosimetric variation in this study is important to the radiotherapy staff in the quality assurance for the prostate VMAT planning.

During the treatment of breast cancer, radiotherapy to the supraclavicular fossa region results in absorption of radiation by the thyroid gland and consequently leads to hypothyroidism in 40% of patients. The aim of this study was to compare thyroid gland radiation absorption during radiotherapy with different anterioposterior beam radiation of 6–15 and 15–15 MV photon beam energies.

In total, 29 patients with breast cancer were recruited to this study. Adjuvant radiotherapy with a total dose of 50 Gy was performed for each participant. Thyroid gland dosimetric measurements were evaluated including, mean dose, minimum and maximum dose, and V20, V30, V40 and V50 (percentage of thyroid volume receiving ≥20, ≥30, ≥40 and ≥50 Gy, respectively). The irradiation delivered doses were measured using Prowess Panther treatment planning system (Version 5.5). All data were evaluated using SPSS software.

In total, 29 subjects with mean age of 53·4±9·4 were studied. According to the obtained results, at 15–15 MV energies, a significantly lower dose was absorbed by the thyroid gland, was observed in contrast to their counterparts who were treated with 6–15 MV photon beam energies.

Using 15–15 MV photon beam energies field can significantly reduce the absorbed dose to the thyroid gland and consequently can reduce the risk of developing hypothyroidism in breast cancer patients treated with radiotherapy.

Bolus material is frequently used on patient’s skin during radiation therapy to reduce or remove build-up effect for high-energy beams. However, the air-gaps formed between the bolus and the skin’s irregular surface reduce the accuracy of treatment planning. To achieve a good treatment outcome using bolus, experimental investigations are required to choose its thickness and to quantify the air-gap effect.

Measurements for a 6 MV photon beam with a fixed source surface distance were carried out using the 31021 Semiflex 3D chamber into the water phantom. Firstly, the depth of maximum dose (R100) and the dose value at surface (Ds) were evaluated as a function of bolus thickness for some square fields. Secondly, to test the effect of the air-gaps ranged from 5 to 30 mm with a step of 5 mm between the bolus and the phantom surface, a water-equivalent RW3 (Goettingen White Water) slab form of 10 mm thickness was considered as a bolus.

We observed that the linear behaviour of R100 in terms of the bolus thickness makes the choice of this parameter more convenient depending on field size. In addition, increasing the air-gaps widens the penumbra and created electrons that have a greater probability to quit the radiation field borders before reaching the surface. The dose spread of the off-field area could have a significant influence on the patient treatment.

Based on dose distribution comparisons between the measurements with and without air-gaps for the field size of 100 mm × 100 mm, it has been demonstrated that a maximum air-gap value lower than 5 mm would be desirable for an efficient use of the bolus technique.

Total body irradiation (TBI) is an external beam radiation therapy in which large field size and extended source skin distances (SSDs) are applied to deliver a therapeutic dose to the whole body. As measurements in such situations are not common and have more uncertainties in comparison to standard dosimetry situations, it is more precise if calculated beam data can be used instead of measurements taken under TBI situations. The purpose of this study is to compare calculated beam data [percentage depth dose (PDD) and dose rate] with those obtained from simulated treatment measurements.

PDD and dose rates were measured for the 6- and 18-MV photon beams under TBI and standard conditions using 9,000 cm3 water phantom and ion chambers (Markus and Farmer). The results were then compared with the calculated PDD and dose rate data. The beam flatness was also measured under TBI and standard conditions for both 6- and 18-MV photon beams, and the results were then compared.

A comparison of the measurement and calculated beam data shows that the difference between calculated and measured PDD values is −6·97 and −4·14% for the 6- and 18-MV photon beams, respectively. The ratio of calculated to measured dose rate was 1·09 and 1·02 for the 6- and 18-MV photon beams, respectively. The beam flatness under TBI conditions was 4·59% for 6-MV and 5·37% for 18-MV photon beam, whereas under standard conditions, these values were 1·50 and 1·98% for 6- and 18-MV radiation beams, respectively.

According to the results, due to a high error level in dose rate and PDD calculations, these parameters must be directly measured under TBI conditions; however, regarding the obtained results, direct measurement is not necessary for the 18-MV photon beam.