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 use cone-beam computed tomography (CBCT) images for treatment planning, the Hounsfield unit (HU)-electron density (ED) calibration table for CBCT should be stable. The purpose of this study was to verify the stability of the HU values for the CBCT system over 1 year and to evaluate the effects of variation in HU-ED calibration curves on dose calculation.

A tissue characterisation phantom was scanned with the field of view (FOV) of size S (FOV-S) and FOV of size M (FOV-M) using the CBCT system once a month for 1 year. A single field treatment plan was constructed on digital phantom images to validate the dose distribution using mean HU-ED calibration curves and possible variations.

HU values for each material rod over the observation period varied with trend. The HU value of the cortical bone rod decreased by about 100 HU for the FOV-S and by about 300 HU for the FOV-M. Possible variation in the HU-ED calibration curves produced a ≤17·9% dose difference in the dose maximum in the treatment plan.

The CBCT system should be calibrated periodically for consistent dose calculation.

The magnetic resonance linear accelerator system (MR Linac) is a novel piece of radiotherapy (RT) equipment allowing the routine application of daily MR-guided treatment adaptation. The hardware design required for such technical capabilities and the increased complexity of the treatment workflow entails a notable departure from cone beam computed tomography (CBCT)-based RT. Patient tolerability of treatment is paramount to RT practice where high compliance is required. Presented is a comparative analysis of how such modality specific characteristics may ultimately impact the patient experience of treatment.

Forty patients undergoing RT for prostate cancer (PCa) on either the MR Linac (n = 20) or a CBCT-based linac (n = 20) were provided with a validated patient reported outcomes measures (PROM’s) questionnaire at fraction 1 and fraction 20. The 18-item questionnaire provided patient responses recorded using a 4-point Likert scale, 0 denoting a response of ‘Not at all’, 1 ‘Slightly’, 2 ‘Moderately’ and 3 signifying ‘Very’. The analysis provided insight into both comparisons between modalities at singular time points (fractions 1 and 20), as well as a temporal analysis within a single modality, denoting changing patient experience.

Patients generally found the MR Linac treatment couch more comfortable, however, found the increase in treatment duration harder to tolerate. Responses for all items remained stable between first and last fraction across both cohorts, indicating minimal temporal variation within a single modality. None of the responses were statistically significant at the 0·01 level.

Whether radiotherapy for PCa is delivered on a CBCT linac or the MR Linac, there is little difference in patient experience with minimal experiential variation within a single modality.

Patients undergoing prostate radiation therapy were observed to have elevated blood pressures in clinic. Therefore, we sought to further characterise this phenomenon.

The charts of 76 patients who received radiotherapy for prostate cancer between 2014 and 2017 were examined. Blood pressure (BP) readings were obtained at initial consultation, on treatment visits, and subsequent follow-up appointments. To describe this effect, we defined radiation-associated hypertension (RAH) as an increase ≥15 mmHg systolic BP, 10 mmHg diastolic BP, or 5 mmHg mean arterial pressure.

Within this cohort, 36 patients developed RAH, with 75% developing RAH while on treatment, and 25% developing RAH at post-treatment visits. Two-thirds of patients remained hypertensive during post-treatment visits, and 27% were prescribed additional anti-hypertensives. There was no association between neoadjuvant/concurrent androgen deprivation therapy and RAH.

A significant number of patients undergoing prostate radiotherapy developed RAH, necessitating additional medication in some.

A retrospective study was undertaken to analyse set-up variations in patients being treated with post-operative radiation therapy for carcinoma of gall bladder by image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) scans and paired kilovoltage beam portals (kVps).

Three consecutive patients receiving post-operative radiation therapy for carcinoma of gall bladder were studied. A total of 32 imaging studies were performed. The immobilisation system was an all-in-one system along with a thermoplastic mask, with knees either resting on the knee rest or in a vacuum cushion. The CBCT scans and kVps were reviewed in an off-line mode. The surrogate markers used for matching during co-registration were 12th rib, coeliac trunk, vertebral bodies and canal. Individual readings were used to calculate mean shifts (m); the mean of these means (M) was calculated to arrive at the systematic error in each direction and its standard deviation (Σ) was calculated. The margins for set-up error (SM) were then calculated.

There were a total of 32 readings of which 21 were CBCTs and 11 were kVps. The mean shifts in each direction for each patient were 0·06, 0·25 and 0·15 cm in vertical, longitudinal and lateral directions, respectively. The resultant planning target volume margins calculated were 0·24, 0·9 and 0·47 cm in vertical, longitudinal and lateral directions.

IGRT for upper abdominal malignancies using CBCT and kVps is a useful method to keep the margins for set-up error low. The use of surrogates for matching should be relevant to the target volume. Good immobilisation system helps in keeping the margins low.

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.

Contrast media are frequently used during radiation therapy simulation. However, there are concerns about dosimetric variations when dose calculation is done on contrast-enhanced computed tomography (CT). This study evaluates the dosimetric effect of oral contrast during three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc radiotherapy (VMAT) planning.

Rectal cancer patients were consecutively enrolled. For each patient, one unenhanced CT and one contrast-enhanced CT were taken using oral and intravenous contrast. Then, a 3D-CRT plan and an Intensity-modulated radiation therapy (IMRT)/VMAT plan were generated in the enhanced CT, and the dose distribution was recalculated in the respective unenhanced CT. The beam intensities were kept the same as for the enhanced CT plans. Finally, the unenhanced and enhanced plans were compared by calculating the gamma index.

For 3D-CRT plans, there were statistically significant differences in second phase planning target volume (PTV) D2% (Mean difference (MD) between unenhanced and enhanced CT 0·01 Gy, 95% CI [0·003 to 0·02 Gy]) and in maximum doses to the bladder (MD 0·26 Gy, 95% CI [0·05 to 0·47 Gy]). For IMRT/VMAT plans, there were statistically significant differences in small intestine V45 Gy (MD 3·1 cc, 95% CI [0·81 to 5·4 cc]), bladder V45 Gy (MD 2·9%, 95% CI [1·4 to 4·3%]) and maximum dose to the bladder (MD 0·65 Gy, 95% CI [0·46 Gy to 0·85 Gy]). In addition, for PTV D98% the MD between unenhanced and enhanced CT was 0·22 Gy 95% CI [0·05 to 0·39].

For most of the dose metrics, the differences were not clinically meaningful. The greatest differences were found in VMAT plans, especially in V45 Gy of the small intestine. This difference could lead to an underestimation of dose–volume metrics when the plan is based on an enhanced CT. The use of small bowel oral contrast does not significantly influence dose calculations and may not affect the acceptability of plans when adhering to constraints.

Nodal boost is being increasingly employed to escalate the dose to involved nodes in node-positive cervical cancer. The study aimed to compare the dosimetric differences between sequential boost intensity-modulated radiation therapy (SeB-IMRT) and simultaneous integrated boost IMRT (SIB-IMRT) in terms of target coverage and organs-at-risk (OARs) with special emphasis on the effect of nodal shrinkage and anatomical change of normal tissues during radiotherapy.

Two computed tomography (CT) datasets (of phase I and phase II) of 40 patients of node-positive cervical cancer treated with SeB-IMRT [planning target volume (PTV) 45/25] followed by SeB to residual nodes (PTV 12·6/7) were utilised. SIB-IMRT1 plan consisted of PTV pelvis and para-aortic nodal region (PTV 45/25) and SIB to gross nodes (PTV 55/25). In order to account for the change in nodal and normal tissue topography during treatment, a third plan (SIB-IMRT2) was generated by utilising the SIB-IMRT1 plan for 44 Gy in 20 fractions and reproducing the plan on the second CT dataset for 11 Gy in 5 fractions. Dosimetric parameters of the three plans were compared using the Friedman test with Bonferroni correction.

We observed that the doses to OARs (bowel, rectum and bladder) were significantly higher in SeB-IMRT plan as compared to the SIB-IMRT plans. V40 Gy of bowel for SeB-IMRT, SIB-IMRT1 and SIB-IMRT2 plans were 354·8 cc, 271 cc and 321·8 cc, respectively (p = 0·001), whereas V30 Gy were 687·8 cc, 635·5 cc and 680 cc, respectively (p = 0·001). The target coverage was marginally better in SeB-IMRT plan as compared to SIB-IMRT1 and SIB-IMRT2 plans (V95% = 99·2 versus 97·7 versus 97·9, respectively, p = 0·000)

SIB-IMRT led to better sparing of OARs, especially bowel. However, the magnitude of benefit decreases if the change in nodal and normal tissue topography during radiotherapy is not considered implying the need for frequent image guidance when SIB-IMRT is planned for node-positive cervical cancer.

In the treatment of locally advanced head and neck cancer (LA-HNC), both dose escalation and hypo-fractionation can improve tumour control rates with uncertain role of addition of concurrent chemotherapy. We aimed at developing a new radiotherapy protocol for patients not eligible to receive the standard concurrent chemo-radiation therapy (CCRT) with little toxicity profile.

A total of 63 LA-HNC patients were randomised to receive either: 70 Gy in 35 fx in 7 weeks concurrently with cisplatin 100 mg/m2 every 3 weeks for 3 doses (Arm A) or 74 Gy in 33 fx in 6·5 weeks (Arm B). Volumetric modulated arc therapy plans were created for both treatment arms. We compared the local control (LC), progression-free survival (PFS), overall survival (OS) and acute and late toxicity between the two arms.

A total of 33 patients were in Arm A versus 30 patients in Arm B with median follow-up 24·2 months. No significant differences in LC, PFS and OS between the two arms. Complete remission occurred in 54·5 and 63·3% of patients in Arms A and B, respectively. All toxicities were significantly less in Arm B than Arm A.

Slightly dose-escalated hypo-fractionated regimen is safe and feasible and has comparable efficacy and less acute and late side effects than conventional dose CCRT with avoidance of chemotherapy-related toxicities in LA-HNC patients.

Locally advanced head and neck cancer can be a distressing disease due to a variety of reasons. This retrospective study looks at the tolerability and outcomes for palliative split-course hypofractionated radiotherapy for this group of patients treated in our centre.

A total of 59 patients were treated with hypofractionated split-course radiotherapy for incurable mucosal squamous cell carcinoma of the head and neck region in our centre over a 10-year period. In all, 71% had stage IV disease. Radiotherapy consisted of three phases of 14·4 Gy/phase, in four to eight fractions over 4 days giving one·8–3·6 Gy/fraction. The phases were separated by 2 weeks. A total of 40 patients (63%) completed all three phases. A total of 72% patients had no acute toxicities and the palliation rate was 83% (complete and partial). Only five patients had no meaningful palliation having completed all three phases. Median duration of local control was 6 months (range: 1–63 months) and median overall survival was 8 months (range: 1–68 months). In five patients, the control was durable with no recurrence at the time of analysis with survival ranging from 6 to 57 months.

We are the first UK centre to report with long-term data, the use of a palliative three phase regime that provides meaningful palliation with acceptable toxicities. In addition, for some patients, it has resulted in durable long-term control.

To compare tumour dose distribution, conformality, homogeneity, normal tissue avoidance, tumour control probability (TCP) and normal tissue complication probability (NTCP) using 3D conformal radiation therapy (3DCRT), 3- and 4-field intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with locally advanced rectal cancer.

Twenty-four patients staged T1–3N+M0 with locally advanced rectal cancer underwent neoadjuvant chemoradiation therapy. Four different radiotherapy plans were prepared for each patient: 3DCRT, 3- and 4-field IMRT and VMAT are evaluated for target distribution using CI and homogeneity index (HI), normal tissue avoidance using Dmax, V45, V40, V50 and TCP and NTCP using the Lyman–Kutcher–Burman model.

VMAT has better HI (HI = 1·32) and 3DCRT exhibited better conformality (CI = 1·05) than the other radiotherapy techniques. With regard to normal tissue avoidance, all radiotherapy plans met the constraints. Dmax in the 3DCRT plans was statistically significant (p = 0·04) for bladder and no significant differences in V40 and V50. In the bowel bag, no significant differences in Dmax for any radiotherapy plan and V40 was lower in 3DCRT than VMAT (p = 0·024). In the case of femoral heads, 3DCRT has a statistically significant lower dose on Dmax than 4-field IMRT (p = 0·00 « 0·05). VMAT has the biggest TCP (80·76%) than the other three radiotherapy plans. With regard to normal tissue complications, probabilities were shown to be very low, of the order of 10-14 and 10-41 for bowel bag and femoral heads respectively.

It can be concluded that 3DCRT plan improves conformity and decreases radiation sparing in the organ at risks, but the VMAT plan exhibits better homogeneity and greater TCP.

Deep inspiration breath hold (DIBH) is a method of motion management used in stereotactic ablative body radiotherapy (SABR) for lung tumours. An external gating block marker can be used as a tumour motion surrogate, however, inter-fraction gross target volume (GTV) displacement within DIBH occurs. This study measured this displacement during a reproducible breath hold regime. In addition, factors such as position of the gating block marker were analysed.

A total of 121 cone beam computed tomography scans (CBCTs) from 22 patients who received DIBH SABR were retrospectively evaluated and the magnitude of inter-fraction GTV displacement was calculated for each fraction. This data was analysed to assess if any correlation existed between tumour displacement and variation in the gating block marker position on the patient, the amplitude of breath hold (BH) at computed tomography (CT), the amplitude of BH at treatment and the tumour location.

The measured tumour displacement was applied to the original planning CT to evaluate the dosimetric effect on surrounding organs at risk (OARs) using cumulative dose volume histograms (DVHs).

BH amplitude was reproducible within 0·13±0·1 cm (mean±standard deviation). The magnitude of tumour displacement within BH ranged from 0 to 1·52 cm (0·41±0·28 cm). Displacement in the superior-inferior, anterior-posterior and left-right planes were 0·31±0·26 cm, 0·16±0·18 cm and 0·07±0·12 cm, respectively. No statistically significant correlation was detected between tumour displacement within DIBH and the factors investigated. The range of variation in OAR dose was −7·0 to +3·6 Gy with one statistically significant increase in OAR dose observed (oesophagus mean dose increasing by 0·16 Gy).

Reproducible BH was achievable across a range of patients. Inter-fraction GTV displacement measured 0·41±0·28 cm. Due to this low level of motion, the correction of soft tissue moves did not adversely affect OAR dose.

Patients with cancer undergoing radiotherapy often develop diarrhoea, causing distress and hindering treatment. As probiotics have favourable effects on the gut flora, they are potentially good candidates in the prevention of radiotherapy-induced diarrhoea (RID).

The outcome of interest of this systematic review was the efficacy of probiotics in preventing RID.

Medline and Embase databases were systematically searched. Four randomised controlled trials (RCTs) were finally selected.

Three RCTs showed beneficial results, which were statistically significant. One RCT showed non-beneficial results, which were not statistically significant. The quality of the studies was mixed, and serious limitations were found.

While the indications are towards a benefit of the use of probiotics in preventing RID, more robust evidence is required in the form of well-designed RCTs.

Stereotactic radiosurgery (SRS) has become a preferred treatment in the initial management of brain metastases (BM). This study reported treatment outcomes and identified the patient, tumour, and treatment-related factors that predict failure, survival, and brain necrosis (BN).

We retrospectively reviewed the electronic medical records of all BM patients treated with SRS. Patient, tumour characteristics and treatment details data were collected. All recurrences and BN were defined in the neurooncological tumour board.

From December 2016 to April 2020, 148 patients were analysed. The median follow-up was 14·8 months (range 6–51). At the time of analyses, 72·3% of the patients were alive. Presence of initial neurological deficit (HR; 2·71 (1·07–6·9); p = 0·036) and prior RT (HR; 2·55 (1·28–5·09); p = 0·008) is associated with worse overall survival. The local recurrence rate was 11·5 %. The distant brain metastasis rate was 53·4 %. Leptomeningeal metastasis was seen in 11 patients (7·4%). Symptomatic BN was seen in 19 patients (12·8 %). Bigger lesions (13 versus 23 mm diameter; p = 0·034) and cavity radiosurgery are associated with more BN (63·2 % versus 36·8%; p: 0·004).

Distant BM is the leading cause of CNS recurrences and, salvage SRS is possible. Due to the increasing risk of developing BN routine metastasectomy should be made with caution.

The impact of COVID-19 social restrictions on mental wellbeing of health professional students during placement is largely unknown. Conventional survey methods do not capture emotional fluctuations. Increasing use of smartphones suggests short message service (SMS) functionality could provide easy, rapid data. This project tested the feasibility and validity of gathering data on Therapeutic Radiography student mental wellbeing during clinical placement via emoji and SMS.

Participants provided anonymous daily emoji responses via WhatsApp to a dedicated mobile phone. Additional weekly prompts sought textual responses indicating factors impacting on wellbeing. A short anonymous online survey validated responses and provided feedback on the method.

Participants (n = 15) provided 254 daily responses using 108 different emoji; these triangulated with weekly textual responses. Feedback concerning the method was positive. ‘Happy’ emoji were used most frequently; social interaction and fatigue were important wellbeing factors. Anonymity and opportunity to feedback via SMS were received positively; ease and rapidity of response engendered engagement throughout the 3-week study.

The use of emoji for rapid assessment of cohort mental wellbeing is valid and potentially useful alongside more formal evaluation and support strategies. Capturing simple wellbeing responses from a cohort may facilitate the organisation of timely support interventions.