Clinical commissioning of online seed matching protocol for prostate radiotherapy

Duffton, A.; McNee, S.G.; Muirhead, R.; Alhasso, Abdulla

doi:10.1259/bjr/72368557

Cited by 4 publications

(8 citation statements)

References 32 publications

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“…Use of internal fiducials with or without cross-sectional imaging Insertion of gold fiducial markers (usually three) in the prostate gland facilitates visualization of the target position and allows for smaller PTV margins due to the ability to localize the prostate on conventional kV portal imaging. 18,53,54 In one study, implantation of fiducial markers allowed PTV margin reduction from 10 to 7 mm as verified by reconstruction of dose distributions after correction using verification CBCT studies. 55,56 In another study, set-up margins calculated to encompass 98% of prostate set-up shifts were 11-14 mm with offline corrections based on alignment to the bone, and the PTV margins needed were reduced to 4-7 mm with the use of online correction using fiducial markers.…”

Section: Use Of Daily Ultrasoundmentioning

confidence: 94%

Target margins in radiotherapy of prostate cancer

Yartsev

2016

BJR

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We reviewed the literature on the use of margins in radiotherapy of patients with prostate cancer, focusing on different options for image guidance (IG) and technical issues. The search in PubMed database was limited to include studies that involved external beam radiotherapy of the intact prostate. Post-prostatectomy studies, brachytherapy and particle therapy were excluded. Each article was characterized according to the IG strategy used: positioning on external marks using room lasers, bone anatomy and soft tissue match, usage of fiducial markers, electromagnetic tracking and adapted delivery. A lack of uniformity in margin selection among institutions was evident from the review. In general, introduction of pre- and in-treatment IG was associated with smaller planning target volume (PTV) margins, but there was a lack of definitive experimental/clinical studies providing robust information on selection of exact PTV values. In addition, there is a lack of comparative research regarding the cost-benefit ratio of the different strategies: insertion of fiducial markers or electromagnetic transponders facilitates prostate gland localization but at a price of invasive procedure; frequent pre-treatment imaging increases patient in-room time, dose and labour; online plan adaptation should improve radiation delivery accuracy but requires fast and precise computation. Finally, optimal protocols for quality assurance procedures need to be established.

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Section: Use Of Daily Ultrasoundmentioning

confidence: 94%

Target margins in radiotherapy of prostate cancer

Yartsev

2016

BJR

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“…Radiation therapists reporting difficult and very difficult found matches challenging as a result of individual marker migration. As it stands, only Thompson et al 19 and Duffton et al 20 have mentioned in their literature what actions should be taken if this occurs. Furthermore, Deegan et al 18 agreed with Chung et al 17 in regards to matching as long as fiducial migration was <2·0 mm.…”

Section: Implications Of Migrationmentioning

confidence: 99%

“…Furthermore, Deegan et al 18 agreed with Chung et al 17 in regards to matching as long as fiducial migration was <2·0 mm. Further to this Duffton et al 20 recognised that infrequent seed migration occurs, stating that in the case of seed loss once again the matching should be done depending on the position of the remaining two seeds or actually match the best fit of the three seeds. 17 Furthermore in instances of significant migration or loss, there is also limited literature on the protocols that should be followed when making decisions about image matching during significant migration and loss.…”

Section: Implications Of Migrationmentioning

confidence: 99%

“…Thus, gold seeds were considered to accurately mimic the prostate when matching with three seeds. 20 More literature is needed to clarify what decisions radiation oncologist will make in different instances of seed loss and seed migration. As it stands, only Thompson et al 19 and Duffton et al 20 have mentioned in their literature what actions should be taken if this occurs.…”

Section: Implications Of Migrationmentioning

confidence: 99%

“…If only one marker was remaining post implantation, then the radiation oncologist should be consulted on whether bony anatomy should be used in matching when treating prostate cancer patients. Further to this Duffton et al 20 recognised that infrequent seed migration occurs, stating that in the case of seed loss once again the matching should be done depending on the position of the remaining two seeds or actually match the best fit of the three seeds. This, however, will introduce interobserver variability in the way each radiation therapist matches 20 .…”

Section: Implications Of Migrationmentioning

confidence: 99%

See 2 more Smart Citations

The stability of seeds in external beam prostate radiotherapy and implications of migration in current practice: a systematic review

Soprun¹,

Sale

Knight³

2014

J Radiother Pract

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Purpose: To determine and summarise the literature on prostatic seed stability by investigating seed marker migration and loss in prostate cancer patients. In addition, documenting the implications of significant seed migration and loss in clinical practise.Methods: PubMed and Sciencedirect databases were used to locate papers on the stability of gold seed markers in prostate patients treated with external beam radiation therapy. The search found 3,238 articles and ten articles were selected and reviewed based on inclusion and exclusion criteria for the scope of this literature review.Results: Minimal migration and loss of seeds was observed in the literature reviewed, with the majority of authors reporting <2·0 mm migration within the prostate; however, there were individual cases reported outside of the 2·0 mm threshold. It was also found that significant migration had an impact on image matching, as well as, planning treatment volume margins.Conclusion: Seed stability within the prostate has been proven, with most authors reporting minimal migration within a 2·0 mm threshold and minimal loss of seeds. Although individual cases can have significant migration and loss, if marker migration exceeds the 2·0 mm threshold, a protocol is required to deal with both non-significant and significant migration.

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Prostate stereotactic body radiotherapy: quantifying intra-fraction motion and calculating margins using the new BIR geometric uncertainties in daily online IGRT recommendations

McNeice

Sanikumar

Alexander

et al. 2023

BJR

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Objectives: To measure the magnitude of intra fraction prostate motion (IFPM) during stereotactic radiotherapy (SBRT) delivered without intrafraction tracking. To assess if current margins adequately cover IFPM. To derive margins using new guidelines Methods: IFPM was determined in 20 patients receiving 36.25 Gy in 5 fractions using 97 pairs of pre and post treatment cone beam CT (CBCT) scans. Correlation of time between CBCT acquisitions and motion was determined. The magnitude of IFM was compared to current margins (6 mm isotropic, 3 mm posterior). Margins were calculated using IFM alone and updated guidelines. The averaged 3D root mean square IFPM was 2.5 mm (4.2 mm). Independent prostate motion was predominantly posterior (70%) and inferior (63%). There was weak correlation between posterior (ρ = 0.38) and inferior (ρ = 0.36) IFPM and time. IFPM greater than current margins occurred in eight of 97 fractions, six in the posterior direction. Margins were ≤3.5 mm using IFM alone and ≤3.3 mm Left3.5mm Right, 7.0 mm inferior, 3.7 mm superior, 4.4 mm anterior and 3.3 mm posterior using new guidelines, compensating for motion in 92% of fractions. Conclusions: Our current SBRT margins account for 92% of IFPM, predominantly posterior and inferior. Although updated guidelines suggest an increase in margins inferiorly, any increase must be balanced against the possibility of increased toxicity, particularly if biochemical control and side-effects are favourable with current practice. Advances in knowledge: The difference between current clinical margins and those determined using updated guidance is demonstrated. The implications must be considered against clinical outcomes.

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Clinical commissioning of online seed matching protocol for prostate radiotherapy

Abstract: This technique can be used within treatment time constraints, benefiting large numbers of patients by helping to avoid geographical miss and potentially reducing toxicity to organs at risk.

Cited by 4 publications

References 32 publications

Target margins in radiotherapy of prostate cancer

Target margins in radiotherapy of prostate cancer

The stability of seeds in external beam prostate radiotherapy and implications of migration in current practice: a systematic review

Prostate stereotactic body radiotherapy: quantifying intra-fraction motion and calculating margins using the new BIR geometric uncertainties in daily online IGRT recommendations

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