The purpose of this study was to dosimetrically compare TomoDirect, TomoHelical and linear accelerator-based 3D-conformal radiotherapy (Linac-3DCRT) for craniospinal irradiation (CSI) in the treatment of medulloblastoma.

Five CSI patients were replanned with Linac-3DCRT, TomoHelical, TomoDirect-3DCRT and TomoDirect-intensity-modulated radiotherapy (IMRT). Dose of 36 Gy in 20 fractions was prescribed to the planning target volume (PTV). Homogeneity index (HI), non-target integral dose (NTID), dose–volume histograms, organs-at-risk (OARs) Dmax, Dmean and treatment times were compared.

TomoHelical achieved the best PTV homogeneity compared with Linac-3DCRT, TomoDirect-3DCRT and TomoDirect-IMRT (HI of 3·6 versus 20·9, 8·7 and 9·4%, respectively). TomoDirect-IMRT achieved the lowest NTID compared with TomoDirect-3DCRT, TomoHelical and Linac-3DCRT (141 J versus 151 J, 181 J and 250 J), indicating least biological damage to normal tissues. TomoHelical plans achieved the lowest Dmax in all organs except the breasts, and lowest Dmean for most OARs, except in laterally situated OARs, where TomoDirect triumphed. Beam-on time was longest for TomoHelical, followed by TomoDirect and Linac-3DCRT.

TomoDirect has the potential to lower NTID and shorten treatment times compared with TomoHelical. It reduces PTV inhomogeneity and better spares OARs compared with Linac-3DCRT. Therefore, TomoDirect may be a CSI treatment alternative to TomoHelical and in place of Linac-3DCRT.

This study was conducted for establishing inherent uncertainty in the shift determination by X-ray volumetric imaging (XVI) and calculating margins due to this inherent uncertainty using van Herk formula.

The study was performed on the XVI which was cone-beam computed tomography integrated with the Elekta AxesseTM linear accelerator machine having six degree of freedom enabled HexaPOD couch. Penta-Guide phantom was used for inherent translational and rotational shift determination by repeated imaging. The process was repeated 20 times a day without moving the phantom for 30 consecutive working days. The measured shifts were used for margins calculation using van Herk formula.

The mean standard deviations were calculated as 0·05, 0·05, 0·06 mm in the three translational (x, y and z) and 0·05°, 0·05°, 0·05° in the three rotational axes (about x, y, z). Paired sample t-test was performed between the mean values of translational shifts (x, y, z) and rotational shifts. The systematic errors were found to be 0·03, 0·04 and 0·03 mm while the random errors were 0·05, 0·06 and 0·06 mm in the lateral, cranio-caudal and anterio-posterior directions, respectively. For the rotational shifts, the systematic errors were 0·02, 0·03 and 0·03 and the random errors were 0·06, 0·05 and 0·05 in the pitch, roll and yaw directions, respectively.

Our study concluded that there was an inherent uncertainty associated with the XVI tools, on the basis of these six-dimensional shifts, margins were calculated and recorded as a baseline for the quality assurance (QA) programme for XVI imaging tools by checking its reproducibility once in a year or after any major maintenance in hardware or upgradation in software. Although the shift determined was of the order of submillimetre order, still that shift had great significance for the image quality control of the XVI tools. Every departments practicing quality radiotherapy with such imaging tools should establish their own baseline value of inherent shifts and margins during the commissioning and must use an important QA protocol for the tools.

To report of long-term results and toxicity profiles using image-guided brachytherapy (IGBT) combined with whole pelvic radiation therapy (WPRT) for cervical carcinoma.

In total, 52 patients with locally advanced cervical carcinoma were enrolled into the study. WPRT was used to treat the clinical target volume (CTV) with a dose of 45–50·4 Gy in 23–28 fractions. IGBT using computed tomography was performed at the dose of 6·5–7 Gy×4 fractions to the minimum dose covering 90% of target volume (D90) of high-risk clinical target volume (HR-CTV).

The mean cumulative dose in equivalent doses of 2 Gy for the D90 of HR-CTV, dose at 2% at refereed volume (D2cc) of bladder, D2cc of rectum and D2cc of sigmoid colon were 92·4, 87·9, 69·6, and 72 Gy, respectively. At the median follow-up time of 61 months, the 5-year local control, disease-free survival, and overall survival rates were 96·2, 75 and 84·6% respectively. Two patients (3·8%) developed grade 3–4 gastrointestinal and two patients (3·8%) developed grade 3–4 genitourinal toxicities.

The combination of WPRT plus IGBT showed very promising long-term results with excellent local control and toxicity profiles.

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.

To measure dosimetric characteristics for linear accelerator-based electron beams, which are applied through locally manufactured acrylic tubes for intraoral radiotherapy and to calculate the secondary cancer risk for organs at risk.

Six different acrylic tubes were exposed to a 6-MeV electron beam; they had tips with three angles (0°, 15° and 30°) and two diameters (2·5 and 3·0 cm). Gafchromic EBT2 film was horizontally and vertically inserted in a solid water phantom to measure the dose profiles and percentage depth doses (PDDs). The measured data from radio-photoluminescence glass dosimeters placed on the neck and both eyes were used to estimate the lifetime attributable risk of secondary cancer resulting from intraoral radiotherapy for tongue cancer.

A total of 12 dose profiles were obtained from six different acrylic applicators at 0·5 and 1·28 cm depths. Circular shapes were obtained from 0° applicators, and oval shapes were obtained from 15° and 30° applicators. Absorbed doses at a 0·5 cm depth were higher than those at a 1·28 cm depth. PDD shapes for the six acrylic applicators were similar to those of a normal 6 MeV electron beam. Larger-diameter applicators showed higher PDD than smaller-diameter applicators with the same tip angle. According to our secondary cancer risk estimation, if 100,000 patients received intraoral radiotherapy at 30 years and lived until 80 years, 122 female and 22 male patients would develop secondary thyroid cancer, while 13 female and 18 male patients would develop secondary ocular melanoma or retinoblastoma.

Dosimetric characteristics for linear accelerator-based intraoperative radiotherapy treatment beam were confirmed. In addition, we found that 0·1% of tongue cancer patients would get secondary malignancies for both eyes and thyroid from this treatment.

To introduce a method to generate a ‘dose–volume histogram (DVH) band’ for plan evaluation of photon therapy and explore its various potentials.

Intensity-modulated radiotherapy (IMRT) plans for head and neck cancer patients were analysed, retrospectively, for setup errors noted during treatment. From the maximum observed random errors, absolute displacement was calculated using Euclidian formula. The original plan with same beam parameters and leaf sequence were used to generate six plans with shifts applied in three axes in six directions. The DVH curves from these six plans were superimposed to form the DVH band. Plans were reviewed with set tolerance criteria.

Method to generate and visualise DVH band was developed. DVH bands were created for 20 patients with head and neck cancer who underwent treatment with IMRT. It was found that seven out these 20 plans were rejected as they crossed the set tolerance criteria using DVH band as an evaluation tool.

DVH band in photon therapy can help the clinician visualise the impact of setup errors at planning and may help select the plan with lesser influence of setup errors over another.

The aim of this study is to develop predictive models to predict organ at risk (OAR) complication level, classification of OAR dose-volume and combination of this function with our in-house developed treatment decision support system.

We analysed the support vector machine and decision tree algorithm for predicting OAR complication level and toxicity in order to integrate this function into our in-house radiation treatment planning decision support system. A total of 12 TomoTherapyTM treatment plans for prostate cancer were established, and a hundred modelled plans were generated to analyse the toxicity prediction for bladder and rectum.

The toxicity prediction algorithm analysis showed 91·0% accuracy in the training process. A scatter plot for bladder and rectum was obtained by 100 modelled plans and classification result derived. OAR complication level was analysed and risk factor for 25% bladder and 50% rectum was detected by decision tree. Therefore, it was shown that complication prediction of patients using big data-based clinical information is possible.

We verified the accuracy of the tested algorithm using prostate cancer cases. Side effects can be minimised by applying this predictive modelling algorithm with the planning decision support system for patient-specific radiotherapy planning.

To perform a retrospective analysis of survival, local–regional control and the effect of prognostic factors in 61 non-small cell lung cancer patients who were treated with postoperative radiotherapy (PORT) by a linear accelerator (LINAC).

A total of 50–66 Gy PORT with a fractional dose of 1·8–2 Gy was administered to 24 patients (24·5%) for surgical margin positivity, 33 patients (54%) for mediastinal lymph node involvement and 13 patients (21·5%) for both mediastinal lymph node involvement and positive surgical margins.

Median follow-up was 17 months, and the median survival and median distant metastasis-free survival were 25 and 19 months, respectively. Local-regional progression was observed in 10 patients (16·4%). Treatment modality (2D/3D) (p=0·021), tumour size >4 cm (p=0·004), surgical margin positivity (p=0·001), and left lung localisation of the tumour (p≤0·05) were the prognostic factors in terms of survival.

A survey of the literature shows that, without PORT, local recurrence or progression rates increase while overall survival rates decrease. In this study, only patients with PORT are studied and the results show that the local progression and overall survival rates are comparable with literature of LINAC-based PORT. In the case of overall survival, 3D treatment shows better results than 2D treatment modality.

This study was conducted for the assessment of in-built systematic and random errors in the ExacTrac imaging system due to the software of Brainlab, on that basis; recommending a new quality control programme for ExacTrac imaging system.

A program was developed to compare the image dataset of real time anthropomorphic pelvic phantom using ExacTrac with the reference image dataset from computed tomography. Images were acquired 20 times in a day, on single sitting for 20 conjugative days. On the basic of these translational and rotational shifts, systematic and random errors were calculated that had arisen due to multiple time image acquisition and image registration between acquired and reference image dataset of the phantom.

Random errors were found as 0·006 cm in right-left (Rt-Lt) direction, 0·008 cm in superior-inferior (Sup-Inf) direction and 0·012 cm in anterior-posterior (Ant-Post) direction. On this basic, margins were calculated using Van Herk formula; it was found that there were 0·02 cm inherent shift in Rt-Lt direction, 0·03 cm in Sup-Inf direction and 0·03 cm in Ant-Post direction.

This study concluded that there was inherent error in ExacTrac system which can be quantified and used as a quality assurance tool for the ExacTrac system.

To determine which concomitant boost technique is dosimetrically superior in the treatment of breast cancer; volumetric-modulated arc therapy (VMAT) or fixed field intensity-modulated radiotherapy (ff-IMRT).

In total, 30 breast patients were re-planned with both VMAT and fixed field concomitant boost intensity-modulated radiotherapy techniques. A hybrid technique was used delivering 80% of the dose through tangential beams and 20% through an integrated boost. A two-tailed t-test sample for means was used to compare the dosimetric differences between the techniques.

Maximum dose was statistically lower for VMAT; 103·2 versus 103·7% for ff-IMRT along with statistically lower V2 Gy doses to the contralateral lung (0·7 versus 1·6%) and heart for both left- (19·0%/22·6%), and right- (5·5%/8·8%) sided patients, respectively. ff-IMRT boasted significantly lower ipsilateral lung V20, V18 and V10 Gy (7·9/8·6/13·1 versus 8·1/8·8/13·4%) than VMAT, respectively. No differences were found with minimum coverage, mean dose and V5 Gy to all organs at risk (OARs).

VMAT and ff-IMRT techniques demonstrate excellent target coverage and OAR sparing facilitated by the hybrid planning technique and deep inspiration breath hold. There is no obvious dosimetrically superior option between the two techniques. Reduced treatment times with VMAT make it more desirable to implement clinically.

We aimed to assess the impact of advanced multileaf collimator (MLC) models and flattening filter-free (3F) beam in volumetric-modulated arc therapy (VMAT)-based craniospinal irradiation (CSI).

CT scans of five medulloblastoma patients who previously received CSI at our hospital were used for the present study. Patients were planned for a prescription dose of 35 Gy to craniospinal axis. A three-dimensional conformal radiotherapy (3DCRT) plan and a VMAT plan using 1 cm MLC leaf width were generated as the gold standard (reference arm). Test VMAT plans were generated using Agility MLC model (MLC leaf width 5 mm) for various combinations of flattened beam (F) and 3F beam for treating the brain and spine planning target volume (PTV). Organs at risks (OARs) were analysed for dose 5, 50, 75 and 90% volumes, mean dose and maximum dose.

All 3DCRT plans and VMAT plans were aimed to cover 95% of PTV by at least 95% prescription dose. VMAT demonstrated lesser dose spillage than 3DCRT to body volume minus PTV (NTID: non tumor integral dose) for a dose threshold above 7·5 Gy. For the low-dose range (1–7 Gy), variation between the dose coverage between all VMAT plans (for either spine or brain PTV) was <1%. Intra-VMAT plan dose variation for all OAR’s for all tested parameters was <1 Gy. Average monitor unit (MU) difference among different VMAT plans ranged between 1·52 and 2·13 when normalised to 3DCRT MU. For VMAT plans, flat beam with 1 cm MLC showed the highest MU, whereas Agility MLC with 3F beam had the least MU values for intra-VMAT plans. No statistical significance variation (p) was observed in between reference arm and test arm plans except for mean dose and V107% for PTV spine. When compared between reference arm 3DCRT and test arm VMAT plans. For OAR’s, no statistical difference was observed between reference and test arm VMAT plans.

Reference arm plans and test arm plans exhibit no statistically significant difference. However, as compared with 3DCRT, VMAT plans are more conformal and produce lesser dose to OAR at the cost of higher delivered MU. 3F beams or finer width MLC’s (width <5 mm) have no advantage over the conventional 1 cm MLC and flat beam except that 3F beams have a shorter beam delivery time. This study demonstrate a significantly lesser spillage dose to NTID/body that of the reported literature, which is attributed to limited rotational arc length used for VMAT plans.

The development of magnetic resonance (MR) imaging systems has been extended for the entire radiotherapy process. However, MR images provide voxel values that are not directly related to electron densities, thus MR images cannot be used directly for dose calculation. The aim of this study is to investigate the feasibility of dose calculations to be performed on MR images and evaluate the necessity of re-planning.

A prostate cancer patient was imaged using both MR and computed tomography (CT). The multilevel threshold (MLT) algorithm was used to categorise voxel values in the MR images into three segments (air, water and bone) with homogeneous Hounsfield units (HU). An intensity-modulated radiation therapy plan was generated from CT images of the patient. The plan was then copied to the segmented MR datasets and the doses were recalculated using pencil beam (PB) and collapsed cone (CC) algorithms and Monte Carlo (MC) modelling.

γ Evaluation showed that the percentage of points in regions of interest with γ<1 (3%/3 mm) were more than 94% in the segmented MR. Compared with the planning CT plan, the segmented MR plan resulted in a dose difference of –0·3, 0·8 and –1·3% when using PB, CC and MC algorithms, respectively.

The segmentation and conversion of MR images into HU data using the MLT algorithm, used in this feasibility study, can be used for dose calculation. This method can be used as a dosimetric assessment tool and can be easily implemented in the clinic.

A novel radiotherapy outlining application uses a small number of user-assigned points across orthogonal planes to generate a mesh which is then edited across multiple slices using innovative three-dimensional (3D) sculpting tools. This paper presents the results of a bladder outlining study that compared times and volumes for the new tool with those of a conventional manual outlining tool.

All students undertaking their first University radiotherapy planning module were invited to participate. Following training, they performed a timed outlining of the same male bladder dataset and provided feedback on their preferred method.

Comparison of times from the resulting ten datasets demonstrated that the 3D segmentation tool was significantly faster than conventional software with a mean time of 11·9 minutes compared with 19·2 minutes (p=0·03). The users expressed a preference for the new tool (eight users) over the conventional outlining software (two users).

A minimal point 3D volumetric manual outlining tool utilising orthogonal computed tomography planes demonstrated significant time saving for bladder segmentation compared with axial-based outlining within a group of novice outliners. Future work aims to establish the role of the 3D multi-slice sculpting tools in editing of auto-segmentation derived contour sets.

This is a dosimetric study to compare the feasibility of carotid artery sparing as a primary objective, as well as planning target volume coverage and dose to spinal cord as a secondary objective, by using 3D conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) for patients with early glottis cancer.

Six patients who had been treated for early stage glottic carcinoma (stage T1-2 N0M0) were included in this study. All patients were immobilised in the supine position with a thermoplastic mask and treatment planning computed tomography scans were obtained from the top of the skull to the top of aortic arch with a 3-mm slice thickness. Two plans were created for every patient, one using 3DCRT and the second using IMRT. Comparison between the two plans was undertaken and analysis was made regarding the dose to the carotids arteries, target coverage and doses to the organs at risk.

For target coverage, the V95% for both plans was the same with no significant difference, hot spots were the highest in 3DCRT with p=0·002, the homogeneity index for IMRT plan was better than 3DCRT (p=0·0001). Regarding the dose to the carotids, it was significantly lower in the IMRT plan compared with the 3DCRT plan (p=0·01). The spinal cord dose was significantly higher in the IMRT plan.

IMRT significantly reduces the radiation dose to the carotid arteries compared with 3DCRT while maintaining clinical target volume coverage. Such a results assists in decreasing the incidence of radiation-induced carotid stenosis, thus improving the quality of life for patients.

Volumetric-modulated arc therapy (VMAT) has emerged as one of the most favourable techniques for radiotherapy treatment in recent years because of its conformal dose distribution to the planning target volume (PTV), lower doses to adjacent normal organs at risk (OARs) and faster and easier dose delivery. A typical conventional VMAT protocol for low-intermediate risk prostate cancer uses a flattened 6 MV photon beam to deliver 78 Gy in 39 fractions, however, a recent Radiation Therapy Oncology Group study investigated prostate cancer radiotherapy with a hypofractionated dose scheme of 36·25 Gy in 5 fractions. One advantage of flattening filter-free (FFF) beams in radiotherapy is the higher doses in the central region on the dose profile and much higher dose delivery rates.

This paper reports the investigation of preclinical studies for implementing FFF beams in hypofractionated VMAT for prostate cancer radiotherapy. All treatment planning were accomplished using Varian EclipseTM treatment planning system version 11 and delivered on Varian Truebeam linear accelerators. The studies compared the biological-effective dose–volume histograms and dose–volume histograms of PTV and OARs for 20 patients using conventional and hypofractionated dose schemes. The study also evaluated the 6 and 10 MV FFF by comparing 6 and 10 MV VMAT plans with the FFF beams. The treatment time was investigated using plans with 6 MV beams and doses of 2, 4, 5, 6, 7·25 Gy/fraction and plans with 10 MV FFF with a dose of 7·25 Gy/fraction. We also investigated an angular monitor unit (MU) quantity (MU/deg) and its threshold value for RapidArcTM plans, beyond which FFF beams can be considered superior to flattened beams in terms of treatment time increased caused by higher dose per fraction.

The results show that the hypofractionated plans resulted in greater biological equivalent doses to PTV and lower doses to OARs. The 10 MV FFF plans have statistically lower mean doses to all the OARs, whereas PTV homogeneity index remains the same compared with other beam energies. The mean body integral dose for the 20 patients is 8·7% lower using 10 MV FFF compared with 6 MV FFF mainly because of the higher energy and less required MUs with the 10 MV FFF beam. The hypofractionated scheme with 10 MV FFF plan has the same treatment time as that of the 6 MV plan at 2 Gy/fraction, as the higher dose delivery rates at 10 MV FFF can compensate for the higher prescribed dose per fraction without the need of extra treatment time.

In this study, we observed that the 10 MV FFF beam is better for hypofractionated prostate cancer VMAT plan delivery. The threshold value of MU/deg is found to be 2·083 MU/deg based on our machine configurations.

The aim of this paper is to compare neural induced changes in three-dimensional conformal radiotherapy (3D-CRT) versus intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for nasopharyngeal cancers.

Radiotherapy plans for 10 patients with nasopharyngeal cancer stages III and IV were prospectively developed for 3D-CRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. Normal tissue complication probabilities were calculated.

The mean planning target volume’s (PTVs) conformity index (CI) for 3D-CRT was 1·424, for IMRT 1·1, and for VMAT 1·081. The PTV homogeneity (HI) index was 0·204 for 3D-CRT, 0·124 for IMRT and 0·153 for VMAT. Normal tissue complication probabilities gave complex results for 3D-CRT, IMRT and VMAT and are analysed in detail in this paper. The mean monitor units were 95 (range 9–180) for 3D-CRT; 165 (range 52–277) for IMRT; and 331 (range 167–494) for VMAT (p<0·05).

VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for nasopharyngeal cancer. VMAT is associated with faster delivery times and greater number of mean monitor units than IMRT. Brain radionecrosis severity and risk, in the past, have been underestimated. By improving the life expectancy of patients with nasopharyngeal cancer to ensure maintenance of the neural structures, recommended dose limits should be considered as a first degree priority (as the spinal cord, brainstem, etc.) when IMRT and VMAT plans are implemented.

Volumetric-modulated arc therapy (VMAT) is an advanced form of intensity-modulated radiation therapy that reduces treatment time without compromising plan quality. This study assessed acute toxicities in patients having carcinomas of oropharynx, larynx and hypopharynx treated with concomitant boost radiation therapy by VMAT.

In this study, 30 patients of stages II–IVA disease were treated with concomitant boost radiation therapy using VMAT and those with stages III and IV also received concurrent chemotherapy with cisplatin 100 mg/m2 weekly thrice for two cycles. The total dose was 68·4 Gy/40 fractions/5.5 weeks (1·8 Gy/fraction/day to the large field for 28 fractions +1·5 Gy/fraction/day to boost field for the last 12 days of treatment). Radiation Therapy Oncology Group acute radiation morbidity scoring criteria was used to grade acute effects.

All patients completed scheduled treatment with median duration of 44 days. No grade 4 skin and mucosal toxicities were observed; grade 3 skin and mucosal toxicities seen in six (20%) and eight (26·67%) patients, respectively; grade 3 dysphagia and laryngeal toxicity in eight (26·67%) and three (10%) patients, respectively; two patients had grade 4 laryngeal toxicity. No grade 3 or grade 4 haematological toxicities were seen.

VMAT-based concomitant boost radiation therapy allows for dose escalation with good patient tolerance by limiting acute toxicities.

Advances in treatment over recent years have increased the long-term survival of young, female cancer patients; unfortunately these treatments bring a significant risk of ovarian failure and infertility. This literature review aimed to determine the optimal technique for ovarian preservation in pre-menopausal women receiving pelvic radiotherapy (IMRT). The traditional method comprises surgical transposition; IMRT and other emerging techniques may offer alternative non-invasive means of sparing ovaries and minimising dose.

A critical review of the evidence pertaining to pelvic radiotherapy and ovarian sparing was performed. Evidence was subjected to critical appraisal using the Critical Appraisal Skills Programme tool and thematic analysis of the findings identified key issues.

Surgical transposition appears to be a successful method of preserving ovarian function depending on the position of the ovaries outside of the radiation field, the age of the patient and the total dose received by the ovaries. There is limited modern evidence concerning its usage in relation to emerging techniques and technology. The use of IMRT is certainly widespread in the treatment of female pelvic cancers, however, there is no evidence supporting its use for reduction of ovarian dose. Several other studies have attempted to demonstrate new techniques to preserve ovarian function, but no functional outcome measures have reinforced their results.

Ovarian transposition has a proven track record for preservation of ovarian function, but the potential value of IMRT as a viable alternative to date remains unexplored. New work should be encouraged to determine the potential value of IMRT as a non-surgical alternative.