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.

The aim of this study was to evaluate whether RapidPlan (RP) could generate clinically acceptable prostate volumetric modulated arc therapy (VMAT) plans.

The in-house RP model was used to generate VMAT plans for 50 previously treated prostate cancer patients, with no additional optimisation being performed. The VMAT plans that were generated using the RP model were compared with the patients’ previous, manually optimised clinical plans (MP), none of which had been used for the development of the in-house RP prostate model. Differences between RP and MP in planning target volume (PTV) doses, organs at risk (OAR) sparing, monitor units (MU) and planning time required to produce treatment plans were analysed. Assessment of PTV doses was based on the conformation number (CN), homogeneity index (HI), D2%, D99% and the mean dose of the PTV. The OAR doses evaluated were the rectal V50 Gy, V65 Gy, V70 Gy and the mean dose, the bladder V65 Gy, V70 Gy and the mean dose, and the mean dose to both femurs.

D99% and mean dose of the PTV were lower for RP than for MP (p = 0·006 and p = 0·040, respectively).V50 Gy, V65 Gy and the mean dose to rectum were lower in RP than in MP (p < 0·001). V65 Gy, V70 Gy and the mean dose to bladder were lower in RP than in MP (p < 0·001). RP had enhanced the sparing of both femurs (p < 0·001) and significantly reduced the planning time to less than 5% of the time taken with MP. MU in RP was significantly higher than MP by an average of 52·5 MU (p < 0·001) and 46 out of the 50 RP plans were approved by the radiation oncologist.

This study has demonstrated that VMAT plans generated using an in-house RP prostate model in a single optimisation for prostate patients were clinically acceptable with comparable or better plan quality compared to MP. RP can add value and improve treatment planning efficiency in a high-throughput radiotherapy department through reduced plan optimisation time while maintaining consistency in the plan quality.

Magnetic resonance imaging (MRI) is indispensable for treatment planning in prostate radiotherapy (PR). Registration of MRI when compared to planning CT (pCT) is prone to uncertainty and this is rarely reported. In this study, we have compared three different types of registration methods to justify the direct use of MRI in PR.

Thirty patients treated for PR were retrospectively selected for this study and all underwent both CT and MRI. The MR scans were registered to the pCT using markers, focused and unfocussed methods and their registration are REGM, REGF, and REGNF, respectively. Registration comparison is done using the translational differences of three axes from the centre-of-mass values of gross tumour volume (GTV) generated using MRI.

The average difference in all three axes (x, y, z) is (1, 2·5, 2·3 mm) and (1, 3, 2·3 mm) for REGF-REFNF and REGF-REGM, respectively. MR-based GTV Volume is less in comparison to CT-based GTV and it is significantly different (p < 0·001).

Image registration uncertainty is unavoidable for a regular CT–MR workflow. Additional planning target volume margin ranging from 2 to 3mm could be avoided if MR-only workflow is employed. This reduction in the margin is beneficial for small tumours treated with hypofractionation.

Nasopharyngeal carcinoma (NPC) patients may have anatomical variations during their radiotherapy treatment course. In this study, we determine the daily accumulated dose by the deformable image registration (DIR) process for comparing with the planned dose and explore the number of fractions which the daily accumulated dose significantly changed from the planned dose.

The validation of the DIR process in MIM software has been tested. One hundred and sixty-five daily megavoltage computed tomography (MVCT) images of NPC patients who were treated by helical tomotherapy were exported to MIM software to determine the daily accumulated dose and then compared with the planned dose.

The MIM software illustrated the acceptable validation for clinical application. The accumulated dose (D50%) of the planning target volume (PTV70) showed a decrease from the planned dose with an average of 0.5 ± 0.27% at the end of the treatment and was significantly different from the planned dose after the second fraction of the treatment (p-value = 0.008). In contrast, the accumulated dose of organ at risk (OAR) tended to increase from the planned dose and was significantly different after the fifth fraction (left parotid), the twelfth fraction (right parotid) and the second fraction (spinal cord).

The inter-fractional anatomic changes cause the actual dose to be different from the planned dose. The dose differences and the number of fractions were varied in each target and OAR. The dose accumulation explored the necessary information for the radiation oncologist to consider adaptive treatment strategies to increase the efficiency of treatment.

As the number of proton therapy facilities has steadily increased, the need for the tool to provide precise dose simulation for complicated clinical and research scenarios also increase. In this study, the treatment head of Mevion HYPERSCAN pencil beam scanning (PBS) proton therapy system including energy modulation system (EMS) and Adaptive Aperture™ (AA) was modelled using TOPAS (TOolkit for PArticle Simulation) Monte Carlo (MC) code and was validated during commissioning process.

The proton beam characteristics including integral depth doses (IDDs) of pristine Bragg peak and in-air beam spot sizes were simulated and compared with measured beam data. The lateral profiles, with and without AA, were also verified against calculation from treatment planning system (TPS).

All beam characteristics for IDDs and in-air spot size agreed well within 1 mm and 10% separately. The full width at half maximum and penumbra of lateral dose profile also agree well within 2 mm.

The TOPAS MC simulation of the MEVION HYPERSCAN PBS proton therapy system has been modelled and validated; it could be a viable tool for research and verification of the proton treatment in the future.

The aim of the study was to find the dosimetric impact of positron emission tomography (PET)-based gross tumour volume (GTV) delineation over computed tomography (CT)-based GTV delineation for carcinoma oesophagus.

Fifteen patients with carcinoma oesophagus were retrospectively selected. Two sets of GTVs in CT plain images were generated, one with the help of intravenous and oral contrast (GTV CT) and the other with only using PET uptake with the standardised uptake value (simple way of determining the activity in PET) (SUV) > 2.5 (GTV PET). Corresponding PTVs were generated. For all patients, rapid arc plans were generated. Changes in target volumes and critical structure doses were evaluated. The Wilcoxon signed-rank test was used for statistical analysis, and p value < 0.05 was assumed as statistically significant.

Mean reduction in GTV was 5.76 ± 19.35 cc. Mean reduction in PTV 45 Gy was 42.40 ± 76.39 cc. Mean reduction in heart mean dose was 1.53 ± 2.16 Gy. Mean reductions in left lung V20% and V10% were 2.43 ± 4.28 and 3.25 ± 5.09 Gy, respectively. Mean reductions in right lung V20% and V10% were 3.11 ± 4.91 and 2.80 ± 4.51 Gy, respectively. Mean reduction in total lung mean dose was 1.00 ± 1.19 Gy.

PET-based GTV contouring reduces the treatment volume and critical structure doses significantly over CT-based GTV contouring for carcinoma oesophagus.

To modify the final dose delivered to superficial tissues and to modulate dose distribution near irradiated surface, different boluses are used. Air gaps often form under the bolus affecting dose distribution. This study aimed to evaluate the effect of an air gap under the bolus radiation on dose delivery.

To evaluate the impact of the air gap, both helical tomotherapy (HT) and direct tomotherapy (DT) were performed in a simulation study.

The maximum dose to bolus in DT plans was bigger than that used in HT plans. The maximum dose delivered to the bolus depended on the air gap size. However, the maximum dose to bolus in all HT plans was within the acceptable value range. Acceptable value was set to up to 107% of the prescription dose. In the simulation performed in this study, the acceptable air gap under bolus was up to 15 mm and below 5 mm in HT and DT plans, respectively.

HT technique is a good choice, but DT technique can be also used if the bolus position can be reproduced accurately. Thus, the reproducibility of the bolus position between planning and treatment is very important.

The purpose of the present study is to compare hybrid [three-dimensional conformal radiation therapy-volumetric-modulated arc therapy (3DCRT-VMAT)] and helical tomotherapy (HT) techniques in terms of both planning target volume (PTV) and organs at risk (OARs) in the plans we made in locally advanced non-small cell lung cancer (NSCLC) patients

Radiotherapy was planned for 15 locally advanced NSCLC patients with 2 different techniques. Large tumours with positive mediastinal lymph nodes were preferred. The prescription dose was determined as 60 Gy at 30 fractions.

Mean PTV volume was 602·5 cc (range: 265–1461). Mean total lung volume was 4264 cc (range: 1885–6803). Homogeneity index, Dmean, Dmax, D2 and V105 were found to be lower in HT, V100, total monitor units (MU) and total beam on time were found to be lower in the hybrid plan. Total lung Dmean was found to be 17 Gy in both techniques. V10 value was 42·85 in the hybrid plan and 48·67 in HT (p = 0·037). Heart Dmean was 14·5 Gy in the hybrid plan and 18·7 in HT (p < 0·001), and V30 values were 18·1 and 22·9, respectively (p = 0·009).

Suitable dose coverage and OAR doses can be provided with both techniques. Especially the opposite lung, heart and oesophagus doses can be kept lower with the hybrid plan, and lower MU and shorter beam on time can be provided.

Mastectomy is a treatment option for patients diagnosed with breast cancer. There is very limited research into the psychosocial impact of mastectomy on female breast cancer patients, especially in the sub-Saharan African setting which has unique cultural norms. The study aimed at assessing the psychosocial impact of mastectomy on female breast cancer patients attending a radiotherapy/oncology centre in Ghana.

A cross-sectional design was used to undertake this study. A total of 80 female mastectomy breast cancer patients participated in this study. A semi-structured questionnaire was used for data collection over a 5-month period, January to May 2018. The data collected were analysed with Statistical Package for Social Science (SPSS) version 22.

Most of the participants were adversely affected psychologically and emotionally by mastectomy. In particular, many (56·7%) agreed that they felt less feminine, and 71% reported they experienced psychological distress as a result of their mastectomy, while 63% of them reported loss of self-confidence. A large proportion of them (51, 63·8%) agreed that their lifestyles had changed following mastectomy, while 58% of them admitted that they felt treated as outcasts by society, and 75% resorted to the use of breast prostheses to reduce attention.

The study revealed that mastectomy for breast cancer patients had a negative impact on their psychological, emotional and social well-being. The availability of affordable breast prostheses, involvement of clinical psychologists in the care of post-mastectomy women, provision of emotional, psychological and even financial support could alleviate the psychosocial impact of affected women.

To investigate the effect of different energies on dose distribution in volumetric-modulated arc therapy (VMAT) plans for head and neck cancer.

Data from nine patients undergoing VMAT plans using 6 MV, 10 MV and dual-energy X-ray beams with the Pinnacle 3 V 9.10 treatment planning system (Philips Medical System, Fitchburg, WI, USA) were analysed for quality using the conformity index (CI) and homogeneity index (HI) for planning target volume (PTV), and for mean and maximum dose to the organs at risk (OARs): parotid glands, brainstem, spinal cord and optic nerves.

There were no clear differences in the HIs of the PTV dose among the different plans. The CIs for 10 MV and dual-energy VMAT plans were superior to that of the 6 MV VMAT plan (0·8 ± 0·3, 0·8 ± 0·3, and 0·7 ± 0·2, respectively; p = 0·001). There were no significant differences in mean/maximum dose to the OARs among the three VMAT plans.

Compared with the 6 MV VMAT plan, the dual-energy VMAT plan slightly increased the coverage of the PTV with the prescribed dose but did not decrease dose to the OARs.

A comparative study was performed about the plan parameters and quality indices between volumetric arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for the treatment of high-risk prostate cancer patients. The aim of this retrospective study was to compare the two methods of external beam radiotherapy IMRT and VMAT in terms of plan quality and efficacy.

Fifteen high-risk prostate patients were planned for radiotherapy using 6 MV photon. Three dose levels were contoured having Planning Tumour Volume 1 (PTV1 = 48 Gy), Planning Tumour Volume 2 (PTV2 = 57.6 Gy) and Planning Tumour Volume 3 (PTV3 = 60 Gy). Setup margins were given using the CHIP trial method. The prescribed PTV3 dose was 60 Gy in 20 fractions which is biologically equivalent to 74 Gy in 37 fractions using α/β = 3. In case of IMRT, seven fixed beam angles 30, 60, 105, 180, 255, 300 and 330 were used and the dose was optimised using the sliding window method. In case of rapid arc technique, one or two full arcs were used for dose optimisation while keeping all the dose constraints and other planning parameters same used in IMRT. The plan evaluation parameters and Organ at risks (OARs) doses were calculated using a dose volume histogram (DVH).

The average D2, D5, D95 and PTVmean for PTV3 were 61.22, 61.13, 58.12, 60.00 Gy and 62.41 62.24 59.53 61.12 Gy for IMRT and VMAT, respectively. The averages V60 for bladder and V30 for rectum were 22.81, 25 and 67, 65% for IMRT and VMAT, respectively. The average homogeneity index (HI), conformity index (CI) and gradient index (GI) were 1.04, 1.4833, 14.79 and 1.04, 1.704, 7.89 for IMRT and VMAT, respectively.

VMAT takes less dose-delivery time and lesser number of monitoring units than IMRT, thus it compensates the intrafractional movements during dose delivery. The Dose GI in VMAT was much better than IMRT. This indicates sharper dose fall off near the normal tissue. No other major differences were observed in terms of plan evaluation parameters between IMRT and VMAT techniques. So, we conclude that VMAT technique is more efficient than IMRT in terms of plan quality and dose delivery.

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.

This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed.

A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method.

Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%).

CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.

Comparison of the integral dose (ID) delivered to organs at risk (OAR), non-target body and target body by using different techniques of craniospinal irradiation (CSI).

Ten CSI patients (medulloblastoma) already planned and treated either with linear accelerator three-dimensional conformal radiation therapy (Linac-3DCRT) technique or with linear accelerator RapidArc (Linac-RapidArc) technique by Novalis-Tx Linac machine have been analysed. Retrospectively, these patients are again planned on Radixact-X9 Linac with Helical, Direct-3DCRT and Direct-intensity-modulated radiation therapy (Direct-IMRT) techniques. The dose prescription to planning target volume brain (PTV-Brain) and PTV-Spine is 36 Gy in 20 fractions and is kept the same for all techniques. The target body, non-target body, OARs and total body dose are compared.

ID is lowest in the RapidArc plan for every patient in comparison to Helical and Direct-IMRT. The ID for Body-PTV was found slightly higher in the RapidArc plan in comparison to 3DCRT plans. But there is better normal tissue sparing for most of the OARs in RapidArc plans if it compares with 3DCRT plans.

RapidArc is a better alternative for the treatment of CSI. It provides better target coverage and better OARs sparing from any other treatment techniques.

To investigate the central electrode artefact effect of different ion chambers in the verification phantom using the dose calculation algorithms Analytical Anisotropic Algorithm (AAA) and Acuros XB.

The dosimetric study was conducted using an in-house fabricated polymethyl methacrylate head phantom. The treatment planning system (TPS)-calculated doses in the phantom with detectors were compared against the dummy detector fillets using AAA and Acuros XB algorithm. The planned and measured doses were compared for the study.

The mean percentage variation in volumetric-modulated arc therapy plans using Acuros XB and the measurement in the head phantom are statistically significant (p-value = 0.001) for FC65 and CC13 chambers. In small volume chambers (A14SL and CC01), the measured and TPS-calculated dose shows a good agreement.

The study confirmed the CT set of the phantom with detectors (FC65 and CC13) give more artefacts/heterogeneity caused a significant variation in dose calculation using Acuros XB. Therefore, the study suggests a method of using phantom CT set with the dummy detector for mean dose calculation for the Acuros XB algorithm.

Total Skin Electron Therapy (TSET) is a specialised radiotherapy technique to treat cutaneous T-cell lymphomas. The purpose of this article is to review different in-vivo dosimetry techniques and to identify further research direction in TSET

Studies focused on in-vivo dosimetry in TSET were included. Studies based on absolute dosimetry in TSET were excluded and no restriction was applied regarding the type of treatment technique and the type of dosimeter.

From the review of articles, we have found that obesity index and patient position during treatment plays a major role in underdose or overdose in TSET. Many studies favour individualised boost dose to patients. The analysis showed that thermoluminescent dosimeters are the most widely used dosimeters in TSET, and time-consuming is the only drawback in the use of dosimetry.

Study showed that the practice of using in-vivo dosimetry would be better way to treat TSET by ensuring accuracy of dose delivery to the patients. Further, only limited studies are available for dosimetry with radiochromic films. With this observation, we have started exploring the use of radiochromic film in our TSET dosimetry, and the results can be analysed to standardise the technique in future.

This technical note describes a quantitative assessment of the production of radioactive materials during a year-long clinical operation of a Mevion S250i Hyperscan proton therapy system. The production of accumulated radioactive materials plays an important role in determining radiation safety in and around the proton therapy facilities.

We have conducted a weekly room survey, every week for a year, during normal clinical operation.

We estimated the accumulated activity from secondary neutron activation on aluminium structures at 3 m away from isocentre in the beamline to be less than 300 μCi.

Radiation-induced malignancies are a rare phenomenon. Post-radiation sarcoma accounts for 0·5–5·5% of all sarcomas. Adjuvant radiotherapy (RT) after surgery plays a significant role in the treatment of breast cancer. Sarcomas of the breast, chest wall, sternum, axilla or supraclavicular region have been reported as a rare complication of RT for breast cancer. Osteosarcoma (OS) of the sternal bone is a rarely reported entity. OS of the sternum secondary to therapeutic ionising radiation is an even rarer diagnosis, and no such cases have been reported in India as per our literature search. Here we report such a case of post-radiation sarcoma after breast cancer treatment—OS presenting in the sternum and both the second ribs in a young lady.

Our patient developed a sarcoma within a previously irradiated field. The latent period was 7·5 years. She initially suffered from a breast carcinoma for which she underwent radical surgery in the form of modified radical mastectomy. She also received 50 Gy RT dose to the chest wall and axilla. She subsequently developed an OS of chest wall in the high-dose region of RT. Another key factor is the high possibility of familial/hereditary cancer inheritance syndrome like Li-Fraumeni in our patient. Though she was never tested for p53 mutations, her young age at first diagnosis (26 years), extremely strong positive family history and spectra of cancers affecting her first-degree blood relatives (brain tumours, leukaemia) strongly hint at the possibility of such a cancer syndrome. Retrospectively, the question certainly arises, given her young age and family history, whether this patient was a right candidate for RT even once as compared to the fact that she received radiation twice.