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The dosimetric benefits of Deep Inspiration Breath Hold (DIBH) in reducing cardiac dose are well documented, however reports on the patient’s personal experience with this technique are limited. The purpose of this research is to investigate DIBH from the patient’s perspective and to provide recommendations to further improve the patient experience.
Materials and methods
A questionnaire was used to record the patient’s comprehension of DIBH instructions and preparation for treatment. Levels of comfort, confidence and technical challenge were also recorded and an open-format question allowed patients to provide suggestions to improve the DIBH experience.
The majority of patients do not find it difficult to hold their breath at the correct level during DIBH and confidence levels regarding ability to follow instructions are good. Comprehension of instructions, preparation to perform DIBH and treatment position comfort levels were universally graded positively.
The majority of patients reported a strong level of comprehension and preparation that allows them to confidently perform DIBH as planned. Establishment of a dedicated treatment team, consistent patient instructions, regular feedback and an opportunity to rehearse DIBH can help increase patient confidence and reduce anxiety.
This study aims to develop an expedited radiotherapy (RT) process and evaluate its time savings in women requiring whole breast RT.
Material and methods
An inter-professional RT team streamlined the computed tomography (CT) simulation and treatment pathway for a ‘QuickStart’ process. Target delineation was performed by an advanced practice radiation therapist and approved by the radiation oncologist (RO) for planning. Automated breast planning software was used for treatment planning and standard quality checks were performed. To assess time savings, the initial 25 QuickStart patients were matched with women who underwent whole breast simulation on the same day (±3 days), treated using the conventional process.
A total of 73 post-lumpectomy women were treated through the QuickStart process; the median consent-to-RT was 2 days (range: 0–13) and the mean CT simulation-to-RT treatment was 2 hours and 42 minutes (SD 0:30). In the subgroup analysis, QuickStart patients saved an average of 11 days from CT simulation-to-RT and had shorter median wait-times for both surgery/chemotherapy-to-RT (60 versus 38 days; p=0·002) and consultation-to-RT (7 versus 20 days; p<0·001).
Through inter-professional team efforts and the application of automated planning software, we have achieved a process that significantly decreases patient wait-times while maintaining the quality of whole breast RT.
There is no consensus on how long the initiation of radiotherapy (RT) can be delayed after surgery without a negative impact on survival.
Materials and methods
We conducted a retrospective study of 278 patients with stage 0–II breast cancer, all of whom were treated with surgery and RT, with those at stages I–II also receiving chemotherapy. Patients were followed-up for 5 years after diagnosis to assess disease-free and overall survival.The independent variable was the delay in the initiation of RT, assessed by two criteria: time since the last treatment, considered acceptable if ≤6 weeks, and time since surgery, considered acceptable if ≤7 months, these cut-offs being used to categorise patients into two groups according to the length of delay.
No statistically significant differences were observed in the probability of disease-free survival (p=0·412) or overall survival (p=0·890). The appearance of recurrence was 5–59 months, with an average of 38·50 (14·31).
Delaying the initiation of RT for more than 6 weeks after last treatment does not seem to have a negative impact on disease-free or overall survival.
The amount of energy deposited on any organ by ionising radiation termed absorbed dose, plays an important role in evaluating the risks associated with the administration of radiopharmaceuticals. In this research work, the absorbed dose received by human organs for 153Sm-TTHMP and 153Sm-PDTMP was evaluated based on biodistribution studies on the Syrian rats.
Materials and methods
153Sm-TTHMP and 153Sm-PDTMP were successfully prepared with radiochemical purity of higher than 99%. The biodistribution of the complexes was investigated within the Syrian rats up to 48 hours post injection. The human absorbed dose of the complexes was estimated by the radiation dose assessment resource method.
The highest absorbed dose for 153Sm-TTHMP and 153Sm-PDTMP was observed in the trabecular bone with 1·085 and 1·826 mGy/MBq, respectively. The bone to other critical organ dose ratio for 153Sm-PDTMP is significantly greater than 153Sm-TTHMP. Also, the bone/red marrow dose ratio for these complexes is comparable with this ratio for 153Sm-EDTMP, as the most clinically used Sm-153 bone pain palliative radiopharmaceutical.
According to the considerable bone absorbed dose against the insignificant absorbed dose of non-target organs, these complexes can be used as potential bone pain palliative agents in clinical applications.
A retrospective planning study comparing volumetric arc therapy (VMAT) and stereotactic body radiotherapy (SBRT) treatment plans for non-small cell lung cancer (NSCLC).
Methods and materials
Five randomly selected early stage lung cancer patients were included in the study. For each patient, four plans were created: the SBRT plan and three VMAT plans using different optimisation methodologies. A total of 20 different plans were evaluated. The dose parameters of dose conformity results and the target dose constraints results were compared for these plans.
The mean planning target volume (PTV) for all the plans (SBRT and VMAT) was 18·3 cm3, with a range from 15·6 to 20·1 cm3. The maximum dose tolerance to 1 cc of all the plans was within 140% (84 Gy) of the prescribed dose, and 95% of the PTV of all the plans received 100% of the prescribed dose (60 Gy). In all the plans, 99% of the PTV received a dose >90% of the prescribed dose, and the mean dose in all the plans ranged from 67 to 72 Gy. The planning target dose conformity for the SBRT and the VMAT (0°, 15° collimator single arc plans and dual arc) plans showed the tightness of the prescription isodose conformity to the target.
SBRT and VMAT are radiotherapy approaches that increase doses to small tumour targets without increasing doses to the organs at risk. Although VMAT offers an alternative to SBRT for NSCLC and the potential advantage of VMAT is the reduced treatment times over SBRT, the statistical results show that there was no significant difference between the SBRT and VMAT optimised plans in terms of dose conformity and organ-at-risk sparing.
Radical hypofractionated thoracic radiotherapy is the most commonly used radiotherapy schedule for inoperable non-small-cell lung cancer (NSCLC) in the United Kingdom, despite a lack of level I evidence to support its use.
To supplement existing published retrospective data with a mature data series and provide further evidence to support the use of this schedule in routine clinical practice.
Materials and methods
Retrospective analysis of all inoperable NSCLC cases treated with radical hypofractionated radiotherapy with or without induction chemotherapy in the North Wales Cancer Treatment Centre between 2001 and 2011.
Of the 222 patients, 209 (94%) received 55 Gy in 20 fractions (#) and 13 (6%) received 52·5 Gy in 20#. Induction chemotherapy was administered in 121 (55%) cases. The median survival of 28·6 months (95% confidence interval 24·2–32·5) is comparable with previously published survival outcomes for this patient group.
The growing body of evidence for this schedule, confirming survival outcomes comparable with internationally accepted results, is sufficient to support its future use in inoperable NSCLC.
This study compared the acute toxicities reported during radiotherapy treatment using either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) to deliver a moderate hypo-fractionated treatment for early-stage prostate cancer.
Material and methods
Acute toxicities are routinely reported at the clinical site for all patients using the Common Terminology Criteria for Adverse Events. Toxicity assessment is performed on day 1 of treatment, then once weekly thereafter. The recorded toxicities of 40 cases treated with five-field IMRT, and 32 cases treated using VMAT were retrospectively compared. All cases were prescribed 73·68 Gy in 28 fractions. Eight symptoms were assessed; diarrhoea, proctitis, fatigue, pain, dermatitis, urinary frequency, urinary retention and urinary tract pain.
In terms of the overall toxicity recorded, VMAT was shown to reduce the toxicities of dermatitis, fatigue, pain and urinary frequency (p<0·05). Using IMRT, grade 2 toxicities were reported for proctitis, pain, urinary frequency, urinary retention and urinary tract pain. Using VMAT, grade 2 toxicities were reported for urinary frequency and urinary retention.
The research reported here is one of the first publications to demonstrate that VMAT is associated with decreased toxicities compared with IMRT for the treatment of early-stage prostate cancer.
Combined modality treatment regimens have provided modest gains in locoregional control rates of cancers of the head and neck (HNC), and intensity-modulated radiation therapy (IMRT) has gained widespread use. The methodology for determining contours of the gross tumour volume (GTV) in the radiation treatment plan is often based on combined anatomic and metabolic data from positron emission tomography–computed tomography (PET-CT). This study aimed to retrospectively evaluate the overall survival and disease-free survival outcomes of patients with HNC who received definitive IMRT with or without chemotherapy, planned with PET-CT.
Materials and Methods
A total of 1,200 patients underwent treatment for HNC during the study period, from 1 January 2002 to 31 December 2010. Of those, 261 cases had evaluable data that met the inclusion criteria for the study. The incidence and timing of locoregional recurrence, distant metastatic disease, new primary malignancies and death were evaluated retrospectively. Overall and disease-free survival (survival to time of first recurrence) were determined by the life table method. Incidence of distance metastatic disease and additional cancers were also studied.
Median follow-up from treatment initiation was 26·4 months (range 1·2–84·7 months). Overall survival and disease-free survival rates were 0·883 and 0·791, respectively, at 1 year; 0·793 and 0·688, respectively, at 2 years; and 0·732 and 0·619, respectively, at 3 years. The cumulative risk of recurrence was 22·6% at 3 years following definitive IMRT and the median time to recurrence was 345 days. There was an overall low incidence of distant metastatic disease (3·07%) and additional cancers (8·05%).
Overall and disease-free survival outcomes of a large cohort of HNC patients treated with definitive IMRT radiotherapy following treatment planning with PET-CT shows a similar high level of disease control and mortality rate as previously published outcome studies of shorter terms and/or smaller numbers of patients.
Cholangiocarcinoma (CCA) or klatskin’s tumour involves malignant tumours at the liver hilum’s biliary confluence. Incidence of CCA results in unresectable tumours that require appropriate therapy to improve quality of life. The liver is considered as the most frequent site of tumour recurrence. Promising results of long-term survival have been established with computed tomography-guided high-dose-rate brachytherapy.
Materials and methods:
Intraluminal brachytherapy (ILBT) is performed through the percutaneous transhapatic bile duct drain tube (PTBD). The passage of the brachytherapy guide tube through the bile duct is more complex compared with oesophageal/endobronchial application.
It results in a recoiled view of the tube in the abdominal region of the computed tomography (CT) scan. Owing to inherent artefacts induced by metal stents in CT scans, intersected view is possible between the ILBT guide tube and the intra-hepatic drain tube. It would mislead the planner to track wrong passage that could result in fatal error.
In this case study, we contoured the ILBT guide tube by cross-verifying its position with a digitally reconstructed radiograph (DRR) before catheter tracking. Thus, it ensures precise simulation of source dwell positions, thereby avoiding high-dose delivery to nearby vital organs such as intestines, liver hilum and blood vessels.
Proliferating trichilemmal tumour (PTT) is a benign tumour originating from the outer root sheath of a hair follicle. In rare instances, malignant transformation has been reported, evidenced by regional or distant metastases. Malignant transformation of PTT is often confused with squamous cell carcinoma. PTT usually occur as a solitary lesion on the scalp. It was first described as a proliferating epidermoid cyst by Wilson-Jones in 1966.
A female patient presented with a growing lesion on scalp in the right parietal region. She had already undergone excision for the same 8 months ago. The cyst was surgically removed and scalp was treated with electron therapy using a field dimension of 8×8 cm in 2011. Now, the patient is disease free with good quality of life.
Oncologists can consider electron therapy in management of PTT. This can improve cosmesis and quality of life of these patients.
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.
Materials and methods
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 dosimetric errors associated with the effect of the collimator angle error in volumetric-modulated arc therapy (VMAT) treatments.
Methods and materials
Four patients with different planning target volume (PTV) and localisations treated using VMAT were analysed (high-risk prostate, low-risk prostate, head and neck (H&N) and holocranial with hippocampus protection) in terms of dosimetric variations when errors in the collimator angle were introduced. Original plans underwent modifications of the planned collimator angles of ±0·5°, ±1° and ±1·5°. These modified plans were re-calculated using the same original plan fluencies, and the resulting dose–volume histograms and homogeneity index (HI-ICRU) were compared.
For the high-risk prostate case, there was a noticeable loss of PTV dose coverage for collimator angle errors larger than ±1°, with HI-ICRU relative variations up to 75% in the range analysed. The low-risk prostate case did not present significant changes in organs at risk or PTV dose coverage. For the H&N case, the spinal cord presented changes around 4% for D0·1 cc. In the holocranial case, optic lens showed dose variations up to 5% for collimator angle errors larger than ±1°.
The effect of the collimator error in VMAT increased as the PTV increased.
For selecting the position of the isocentre, one should be cautious, and whenever possible choose a position close to the geometrical centre of the PTVs in order to avoid or minimise errors from the calibration of the collimator angle.