This study aims to evaluate dosimetric parameters like percentage depth dose, dosimetric field size, depth of maximum dose surface dose, penumbra and output factors measured using IBA CC01 pinpoint chamber, IBA stereotactic field diode (SFD), PTW microDiamond against Monte Carlo (MC) simulation for 6 MV flattening filter-free small fields.

The linear accelerator used in the study was a Varian TrueBeam® STx. All field sizes were defined by jaws. The required shift to effective point of measurement was given for CC01, SFD and microdiamond for depth dose measurements. The output factor of a given field size was taken as the ratio of meter readings normalised to 10 × 10 cm2 reference field size without applying any correction to account for changes in detector response. MC simulation was performed using PRIMO (PENELOPE-based program). The phase space files for MC simulation were adopted from the MyVarian Website.

Variations were seen between the detectors and MC, especially for fields smaller than 2 × 2 cm2 where the lateral charge particle equilibrium was not satisfied. Diamond detector was seen as most suitable for all measurements above 1 × 1 cm2. SFD was seen very close to MC results except for under-response in output factor measurements. CC01 was observed to be suitable for field sizes above 2 × 2 cm2. Volume averaging effect for penumbra measurements in CC01 was observed. No detector was found suitable for surface dose measurement as surface ionisation was different from surface dose due to the effect of perturbation of fluence. Some discrepancies in measurements and MC values were observed which may suggest effects of source occlusion, shift in focal point or mismatch between real accelerator geometry and simulation geometry.

For output factor measurement, TRS483 suggested correction factor needs to be applied to account for the difference in detector response. CC01 can be used for field sizes above 2 × 2 cm2 and microdiamond detector is suitable for above 1 × 1 cm2. Below these field sizes, perturbation corrections and volume averaging corrections need to be applied.

Monte Carlo (MC) simulations have been used extensively for benchmarking photon dose calculations in modern radiotherapy using linear accelerators (linacs). Moreover, a major barrier to widespread clinical implementation of MC dose calculation is the difficulty in characterising the radiation source using data reported from manufacturers.

This work aims to develop a generalised full MC histogram source model of an Elekta Precise SL-25 linac (electron exit window, target, flattening filter, monitor chambers and collimators) for 6 MV photon beams used in standard therapies. The inclusion of many different probability processes such as scatter, nuclear reactions, decay, capture cross-sections and more led to more realistic dose calculations in treatment planning and quality assurance.

Two different codes, MCNPX 2·6 and EGSr-BEAM, were used for the calculation of particle transport, first in the geometry of the internal/external accelerator source, and then followed by tracking the transport and energy deposition in phantom-equivalent tissues. A full phase space file was scored directly above the upper multilayer collimator’s jaws to derive the beam characteristics such as planar fluence, angular distribution and energy spectrum. To check the quality of the generated photon beam, its depth dose curves and cross-beam profiles were calculated and compared with measured data.

In-field dose distributions calculated using the accelerator models were tuned to match measurement data with preliminary calculations performed using the accelerator information provided by the manufacturer. Field sizes of 3×3, 5×5, 10×10, 15×15 and 20×20 cm2 were analysed. Local differences between calculated and measured curve doses beneath 2% were obtained for all the studied field sizes. Higher discrepancies were obtained in the air–water interface, where measurements of dose distributions with the ionisation chamber need to be shifted for the effective point of measurement.

The agreements between MC-calculated and measured dose distributions were excellent for both codes, showing the strength and stability of the proposed model. Beam reconstruction methods as direct input to dose-calculation codes using the recorded histograms can be implemented for more accurate patient dose estimation.

To evaluate the efficacy of a Belly Board immobilisation device for rectal cancer patients.

A randomised trial in patients receiving neo-adjuvant chemoradiation for rectal carcinoma was established. Patients were treated, prone with control arm, according to standard departmental protocol and experimental arm with the use of a Belly Board. All treatments were planned using a three-field technique. The primary endpoints were reproducibility and irradiated small bowel volume. Questionnaires were used to assess secondary endpoints of patient comfort, ease of set-up and acute toxicities.

Pre-planned interim analysis was performed after recruiting 30 patients. In all, 348 portal images were analysed retrospectively. Around 8 out of 12 parameters measuring set-up reproducibility were in favour of the Belly Board arm. Random error in the anterior–posterior direction was improved and statistically significant in the experimental arm (95% CI; p≤0·05). Small bowel V15 was significantly lower in the Belly Board position (mean V15=14·5%) compared with the standard position (mean V15=21·4%), paired t-test 95% CI; p=0·035. Also, patients’ comfort satisfaction was greater in the Belly Board arm.

Set-up reproducibility, small bowel V15, patient comfort and satisfaction were all significantly improved by the use of the Belly Board.

Pancreatic cancer is the 12th most commonly diagnosed cancer and the 3rd leading cause of cancer mortality and accounts for approximately 2·7% of all newly diagnosed cancer cases and 6·4% of all cancer mortalities in Canada. It has a very poor survival rate mainly due to the difficulty of detecting the disease at an early stage. Consequently, in the advancement of disease management towards the concept of precision medicine that takes individual patient variabilities into account, several investigators have focused on the identification of effective clinical biomarkers with high specificity and sensitivity, capable of early diagnosis of symptomatic patients and early detection of the disease in asymptomatic individuals at high risk for developing pancreatic cancer.

We searched several databases from August to December 2020 for relevant studies published in English between 2000 and 2020 and reporting on biomarkers for the management of pancreatic cancer. In this narrative review paper, we describe 13 clinical and emerging biomarkers for pancreatic cancers used in screening for early detection and diagnosis, to identify patients’ risk for metastatic disease and subsequent relapse, to monitor patient response to specific treatment and to provide clinicians the possibility of prospectively identifying groups of patients who will benefit from a particular treatment.

Current and emerging biomarkers for pancreatic cancer with high specificity and sensitivity has the potential to account for individual patient variabilities, for early detection of disease before the onset of metastasis to improve treatment outcome and patients’ survival, help screen high-risk populations, predict prognosis, provide accurate information of patient response to specific treatment and improve patients monitoring during treatment. Thus, the future holds promise for the use of effective clinical biomarkers or a panel of biomarkers for personalised patient-specific targeted medicine for pancreatic cancer.

This is the second of two papers giving an overview of the use of Monte-Carlo techniques for radiotherapy applications.

The first paper gave an introduction and introduced some of the codes that are available to the user wishing to model the different aspects of radiotherapy treatment. It also aims to serve as a useful companion to a curated collection of papers on Monte-Carlo that have been published in this journal.

This paper focuses on the application of Monte-Carlo to specific problems in radiotherapy. These include radiotherapy and imaging beam production, brachytherapy, phantom and patient dosimetry, detector modelling and track structure calculations for micro-dosimetry, nano-dosimetry and radiobiology.

This work reports our study to commission a radiochromic film dosimetry system using the timely EBT3 film. We carried out dosimetric evaluations on different characteristics of photon beams (e.g., flatness, symmetry and penumbra) in radiation dose delivery.

A Varian linear accelerator producing 6 and 15 MV photon beams with 120 multi-leaf collimator was used in this study. PTW ionisation chamber was used to measure the beam characteristics such as symmetry, flatness and penumbra and these measurements were used to commission the radiochormic EBT3 film dosimetry system. The results of irradiated films were analysed using the radiochromic film QA Pro software 2016.

The measured film doses were analysed at two different colour channels (green and red) using two scanning geometries (i.e., upper or lower side of film facing the scanner light source) at two dose levels (10 and 40 Gy). The difference between the ionisation chamber and film results was found insignificant and within the acceptable range as per the World Health Organisation standard.

Results of the comparison between the ionisation chamber and film measurements show that our radiochormic EBT3 film dosimetry system is reliable and cost-effective in the output measurement of a linear accelerator. Our measurements confirm that our EBT3 film dosimetry agreed well with the ionisation chamber, and can be used as a re-validation tool for linear accelerator quality control.

The incidence of breast cancer has surpassed cervical cancer in India and it has now become the most common cancer in women. Multiple randomised studies have reported low α/β value in the range of 3–4 for breast cancer, which predict a potential radiobiological advantage for hypofractionated radiotherapy resulting in such schedules becoming standard in many centers with reduction in overall treatment time. Volumetric modulated arc therapy (VMAT) is a novel technique of delivering radiotherapy that reduces treatment delivery time, requires less monitor units (MU) and offers good conformity. The mean dose to normal tissue may be minimised using this technique although there will be inferior sparing if we consider the low-dose volume such as V5, the effect of which is not quantifiable yet.

Reporting acute toxicity, cosmetic effects, and quality of life in patients of early breast cancer treated with adjuvant hypofractionated VMAT with SIB.

The records of 44 patients registered at the hospital between August 2014 and December 2015 were included in this analysis. Acute toxicities were analysed using CTCAE v4.03. Cosmetic outcomes were assessed using Harvard scale, while quality of life outcomes were assessed using EORTC scales and Health Related quality of life (HRQOL) questionnaires (QLQ-C30 and QLQ-BR23).

No grade ≥2 skin toxicities were recorded. Breast pain was recorded as Grade 1 in 13·8% patients and Grade 1 fatigue in 18·2%. The maximum haematological abnormality grade recorded was Grade 1. Cosmesis was assessed at the baseline, 6 months, 1 year and 2 years. A total of 88·6% of the patients had an Excellent or good cosmesis at the baseline, which was similar even at 6 months, at 88·7%, improved further at 1 year to 90·9%. At 6 months post radiotherapy, high functional scale QOL scores were noted.

The technique is associated with minimum acute toxicity, good to excellent cosmesis and acceptable quality of life.

In this work, dosimetric properties of the PTW Octavius detector in and out of the irradiation field have been evaluated. The 2D array of ion chambers has the potential to simplify the linear accelerator QA and pre-treatment verification.

The evaluation was performed using customised written codes in Matlab and SPSS software for statistical analysis.

Experiments indicate that the reproducibility and stability of the measurements were excellent; the detector showed the same signal with a maximum deviation of <0·5% in the short and long term. Comparisons of the ion chamber with the detector showed the same results with a maximum deviation of ~0·1%. As the detector response is linear with the dose, it can be used for the measurement at regions of high-dose gradient effectively. Logarithmic regression y=0·127 ln(x)+0·729 for detector signal and field size changes yielded a coefficient of determination of 0·997. The dose value decreases with increase in source-to-surface distance, which was modelled using a binomial regression with a coefficient of determination of 0·998 that agrees with the ionisation chamber measurement within 1%.

On the basis of the measurements and comparisons performed, this system is a reliable and accurate dosimeter for quality assurance in radiotherapy.

The purpose of this study was to develop the patient-specific quality control (QC) process by most commonly used dosimeters in Bangladesh and recommend a suitable passing rate for QC, irrespective of the dosimetric tools used.

Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans of five head-and-neck (HN) and five prostate patients were selected for the patient-specific QC. These plans were generated using the Eclipse TPS v11·0 (Varian Medical Systems, Inc., Palo Alto, CA, USA) 6 MV X-ray from a Varian TrueBeam linear accelerator (Varian Medical Systems, Inc.) for each case. Each IMRT and VMAT plans were measured by two-dimensional (2D) ion chamber arrays (I’matriXX) and electronic portal imaging devices (EPID), respectively. The passing rates of the dosimetric tools were calculated using criteria of 3%/3 mm.

The average passing rates (±SD) of I’matriXX for prostate and HN were 97·9±0·76 and 98·88±0·24, respectively. For VMAT verification, the average passing rates of EPID for prostate for arc1 and arc2 were 96·15±0·49 and 97·8±0·70, respectively; similarly, for HN the rates were 97·85±0·63 and 97·2±0·56, respectively.

The results showed that both the dosimeters can be used in patient-specific QC, although the EPID-based IMRT and VMAT QC is more advantageous in terms of time-saving and ease of use. Hence, for patient-specific QC, one can use the ion chamber arrays (I’matriXX) or EPID in hospital, but the systems need to be cross-checked.

Therapeutic radiographers routinely offer advice to patients regarding treatment-related side effects. Cranberry has long been used as a natural remedy for several health complaints and has more recently been suggested as having a role in the treatment and prophylaxis of urinary tract infection (UTI) and symptoms.

The aim of this review was to investigate whether there is a place for cranberry as part of the management of radiation cystitis caused by radiotherapy treatment of pelvic cancers, in order to aid therapeutic radiographers in tailoring their advice regarding pelvic side effects.

A structured search was carried out using PubMed, CINAHL, Scopus and Cochrane Library databases. A total of 25 articles were selected for review.

Themes of mechanism of action of cranberry, composition of cranberry products, cranberry and UTI, use of cranberry in radiotherapy and further issues to consider were identified and explored.

A lack of high-quality data was identified in the literature reviewed and no firm evidence was found to support the continued recommendation of cranberry as part of management of radiation induced urinary tract side effects. Well-designed randomised controlled trials are required before further recommendations regarding the use of cranberry in radiotherapy are made.

This study aims to evaluate the application of the exit skin dose (ESD) in verifying the accuracy of intra-cavitary brachytherapy treatments performed by the BEBIG 60Co machine using thermoluminescent dosimeters (TLDs).

Eleven patients who were treated for gynaecological (GYN) malignancy by high-dose-rate (HDR) brachytherapy machine have been considered in this study. A combination of tandem, cylinder and interstitial needles was applied for eight patients while tandem ovoid (TO) applicators were used for the rest (three patients). In order to measure ESD, thermoluminescent dosimetry was performed for each patient. TLDs were placed precisely on the patient’s skin along her symphysis pubis bone (anterior) and left (L)/right (R) sides of her pelvic. Positioning of the dosimeter was accurately determined using fiducial markers in computed tomography (CT) scan imaging, prior to the treatment. Finally, a comparison was made between the calculated dose from the treatment planning system (TPS) and the dose measured by TLDs.

About 90% of all cases showed a good agreement (while considering TLD uncertainty ∼5·5%) between TPS dose calculations and TLD measurements. The measured mean values of ESD received to anterior, left and right positions were 56·72, 12·18 and 12·82 cGy, respectively. For three patients, differences up to 11·9% were detected.

To conclude, ESD measurement method can be a suitable practical approach for verifying the accuracy of GYN HDR treatment delivery.

This work aims to evaluate the effect of Hitachi 16-slice scanner reconstruction filters on Hounsfield unit (HU) variations. In the literature, there is a lack of information from a wide variety of scanners in this regard. In addition, not all studies have investigated the effect of reconstruction filters on HU in an exhaustive way.

The computerised imaging reference system electron density phantom (model 062M) was scanned with different substitute materials of different density from Hitachi 16-slice computed tomography. The raw images were obtained with four tube voltage settings: 80 kVp, 100 kVp, 120 kVp and 140 kVp. The raw images for each energy level were then reconstructed using different reconstruction filters.

The HU values of dense bone were significantly different when changing the reconstruction filters without beam hardening correction (BHC). Nevertheless, when selecting the BHC, this variation decreases heavily for 80 kVp and decreases slightly for 140 kVp, but it remains outside the tolerance of ±50 HU. However, for 100 kVp and 120 kVp, the differences in HU values become within the tolerances indicated for dense bone.

Changing image reconstruction filters during a dosimetric scan had a significant effect on HU in dense bone. Therefore, it is recommended to evaluate this effect during the commissioning phase. As a result, this study provides a methodology to comprehensively investigate the effect of reconstruction filters on HU.